Wednesday, September 28, 2016

How statins aid the immune system

Statins protect against cardiovascular disease in more ways than previously thought. In a study, researchers from Karolinska Institutet are able to show the immunological effects of statins, and present a new hypothesis on why statins are effective at preventing heart attacks. The study is published in The Journal of the American Heart Association.

Atherosclerosis can lead to a number of serious medical conditions, such as heart attack, stroke and intermittent claudication. These and other cardiovascular diseases are on the increase around the world, and are the leading causes of death in the west. Johan Frostegård, professor at KI's Institute of Environmental Medicine, has had a long-standing interest in atherosclerosis and the possible underlying causes of this chronic inflammation. Atherosclerosis is visible on the blood vessel walls as plaque consisting of accumulated dead cells and oxidised (rancid) LDL cholesterol (the so-called "bad" cholesterol) and two types of immune cell, T cells and dendritic cells, which are the key players in this chronic inflammation.

Statins are a common class of drug often used to prevent cardiac arrest and other such conditions. Even though it has long been known that statins are anti-inflammatory, it is unclear whether the immune system is more specifically affected, the assumption having been that statins are so effective because they reduce levels of cholesterol in the blood.

"We can show how statins can protect against cardiovascular disease through a new, specific immunological mechanism, and I believe that this can explain much of their beneficial effect," says Johan Frostegård, professor of medicine at Karolinska Institutet's Institute of Environmental Medicine and consultant at Karolinska University Hospital's Emergency Clinic. "For the first time, we're able to show that an immunological treatment for atherosclerosis can actually work."

The researchers studied the interaction between the two most important immune cells in this context, T cells and dendritic cells. By looking at atherosclerotic plaque sourced direct from operations on human patients, they found that oxidised LDL-cholesterol activates inflammatory T cells from plaque via the dendritic cells. The statins block the T cells and stimulate the production of anti-inflammatory T cells (T regulatory cells). The dendritic cells are also affected in a way that renders them anti-inflammatory.

When the side-effects of statins are discussed, their possible carcinogenic properties are sometimes addressed. While large-scale metastudies have shown that there is a reduction in most kinds of tumour, in this study it was discovered that statins repress gene activators (microRNA), including a certain kind called let7c, which normally helps to inhibit tumour growth. In this study, let7c was involved in oxidized LDL-induced T cell activation.

"Statins severely repressed let7c," says Professor Frostegård. "If a patient has a tumour in which let7c plays an important part, the statin effect could be adverse. At the same time, statins reduce inflammation and that can lower the risk of cancer, and large metastudies show no general increase in cancer risk."

Interval exercise training improves blood vessel function in older adults

Resistance-based interval exercise helps improve endothelial function -- including blood flow and blood vessel dilation -- both in older adults with type 2 diabetes and in age-matched non-exercisers and regular exercisers, according to new research published in the American Journal of Physiology -- Heart and Circulatory Physiology. The results suggest that increasingly popular interval exercise plans could be used to treat endothelial dysfunction in older adults.

"The endothelium plays a pivotal role regulating the many factors that determine vascular tone, tissue perfusion, coagulation and inflammation. Endothelial dysfunction is an early manifestation in many chronic diseases, including diabetes, and contributes to the [approximately two- to four-fold] greater risk of cardiovascular disease in type 2 diabetes," the researchers wrote. For the estimated 28 million people with type 2 diabetes in the U.S., endothelial problems can impair blood flow and lead to nerve damage and other complications.

Interval training alternates periods of high- and low-intensity exercise. Many people find interval training appealing because of the relatively short time commitment required and because rest periods are built into the exercise time. In this study, researchers compared resistance (using weighted leg resistance exercises) and cardiovascular (using a stationary bicycle) interval training to see how the exercise regimens affected endothelial function. Thirty-five volunteers (average age 56) were assigned to three groups: people with type 2 diabetes (T2D), non-exercisers without diabetes (UN-NG) and regular exercisers without diabetes (TR-NG). Each group performed the same 20-minute exercise regimen: three-minute warm up; seven one-minute (resistance or cardio) interval workout with a one-minute rest between each interval; three-minute cool down. The researchers measured blood flow in the brachial artery in the upper arm before and immediately following interval training and at one and two hours post-exercise.

The researchers found that all of the exercisers -- with or without diabetes, trained or untrained -- saw an improvement of flow-mediated dilation (FMD%, a measure of endothelial function) after resistance-based interval training. This was especially true in the T2D group, which experienced FMD% improvement at each measurement period. Cardiovascular interval training led to FMD% changes after one hour in the T2D group and after two hours in the regular exercise group but did not cause any improvement in the non-exercising group.

"This study shows that resistance-based interval exercise is a time-efficient and effective exercise method to acutely improve endothelial function in T2D, age-matched UN-NG and TR-NG participants," the researchers wrote. "These findings warrant the examination of the long-term impact of [resistance-based interval exercise] on vascular function."

Monday, September 26, 2016

Eating raw apple or lettuce may help reduce garlic breath

Garlic -- consumers either love or hate the taste, but one thing is for certain, no one likes it when the scent of it sticks around on their breath. Now, garlic lovers may have a new solution to their halitosis problem. A study published in the September issue of the Journal of Food Science found that eating raw apple or lettuce may help reduce garlic breath.

Researchers from the Ohio State University gave participants three grams of softneck garlic cloves to chew for 25 seconds, and then water (control), raw, juiced or heated apple, raw or heated lettuce, raw or juiced mint leaves, or green tea were consumed immediately. The volatiles responsible for garlic breath include diallyl disulfide, allyl mercaptan, allyl methyl disulfide, and allyl methyl sulfide. The levels of volatiles on the breath after consumption were analyzed by selected ion flow tube mass spectrometry.

Raw apple and raw lettuce and decreased the concentration of volatiles in breath by 50 percent or more compared to the control for the first 30 minutes. Mint leaves had a higher deodorization level compared to raw apple and raw lettuce for all volatile compounds measured. Apple juice and mint juice reduced the levels of volatiles, but not as effectively as chewing raw apple or raw mint. Both heated apple and lettuce produced a significant reduction of volatiles. Green tea had no deodorizing effect on the garlic compounds.

According to the researchers, foods deodorize garlic breath through two mechanisms. First, enzymes in the raw foods help to destroy the odors, and then, phenolic compounds in both the raw and cooked foods destroy the volatiles. This is why raw foods were generally more effective because they contain both the enzymes and the phenolic compounds.

Yoga may not count toward 30 minutes of daily physical activity, but may have other benefits

Hatha yoga is an increasingly popular form of physical activity and meditative practice in the U.S. It is important to understand the calorie cost and intensity of yoga in relation to the national physical activity guidelines, such as those recommended by the American College of Sports Medicine (ACSM) and the American Heart Association (AHA). These guidelines encourage 30 minutes of moderate-intensity physical activity on most days of the week.

This study was a systematic review that evaluated published research investigations that have directly measured the calorie cost of yoga and calculated the metabolic intensity (METS) of individual yoga poses including a popular sequence called "sun salutations."

Based on ACSM/AHA classification, the intensity of holding most poses and of full yoga sessions ranged from light (less than 3 METS) to moderate-intensity (3-6 METS), with the majority classified as light-intensity.

A few sequences/poses, including the sun salutations, met the criteria for moderate-intensity activity. The health benefits of yoga, however, should not be discounted. The regular practice of yoga may also increase strength, balance and flexibility, calm the mind and reduce stress.

Physical activity lowers the risk of urinary tract infections

The risk of viral infections is known to be affected by physical activity, but little information is available regarding the more serious infections caused by bacteria.

In this study, the investigators examined the relationship between leisure-time physical activity and suspected bacterial infections during a one-year follow up.

Suspected bacterial infections were determined based on prescriptions for antibiotics. Via the use of Denmark's unique civil registration number (an identification number assigned to all citizens at birth), it was possible to link health survey information with information from nationwide registries.

Results showed that compared with sedentary behavior, low leisure-time physical activity was associated with a 10 percent lower risk of any suspected bacterial infection.

Further, low and moderate levels of leisure-time physical activity were associated with a 21 percent and 32 percent reduction of suspected cystitis (urinary tract bacterial infections), respectively -- compared with individuals classified as sedentary. Suspected respiratory tract bacterial infections, however, were not associated with physical activity level.

Friday, September 23, 2016

Low concentration of fish oil in the blood and lack of physical activity contribute to the high levels of depressed mood

Low concentration of fish oil in the blood and lack of physical activity may contribute to the high levels of depressed mood among soldiers returning from combat, according to researchers, including a Texas A&M University professor and his former doctoral student.

In a study titled "Fatty Acid Blood Levels, Vitamin D Status, Physical Performance, Activity and Resiliency: A Novel Potential Screening Tool for Depressed Mood in Active Duty Soldiers," researchers worked with 100 soldiers at Fort Hood to identify which factors affected moods in returning soldiers.

The research was conducted by Major Nicholas Barringer when he was a Texas A&M doctoral student under the direction of Health & Kinesiology Professor and Department Head Richard Kreider, in collaboration with several current and former members of the U.S. Army, and colleagues at Texas A&M.

"We looked at how physical activity levels and performance measures were related to mood state and resiliency," Kreider says. "What we found was the decrease in physical activity and the concentration of fish oil and Omega-3s in the blood were all associated with resiliency and mood."

Kreider says fish oil contains Omega-3 fatty acids that help to boost brain function. He says studies also show that fish oil acts as an anti-inflammatory within the body -- helping athletes and soldiers manage intense training better. Fish oil content is especially important for soldiers due to the consistent training and physical regiments performed in and out of combat and risk to traumatic brain injury.

The study originated from research conducted by Colonel Mike Lewis, M.D. who examined Omega-3 fatty acid levels of soldiers who committed suicide compared to non-suicide control and found lower Omega-3 levels in the blood were associated with increased risk of being in the suicide group.

Barringer says he believes these findings to be significant toward addressing some of the issues many soldiers face.

"The mental health of our service members is a serious concern and it is exciting to consider that appropriate diet and exercise might have a direct impact on improving resiliency," Barringer notes.

In order to properly measure soldiers physically, Kreider and Barringer developed a formula they say has the potential to assist in effectively screening soldiers with potential PTSD ahead of time. The formula measures a number of factors including: fitness and psychometric assessments, physical activity, and additional analysis.

"By improving resiliency in service members, we can potentially decrease the risk of mental health issues," Barringer says. "Early identification can potentially decrease the risk of negative outcomes for our active service members as well as our separated and retired military veterans."

"The military is using some of our exercise, nutrition, and performance-related work and the findings may help identify soldiers at risk for depression when they return from combat tours," Kreider notes. He says that by working to identify such high-risk issues faced by soldiers, it can set a precedent that will benefit not only military leadership, but also the general public.

"The public must realize that our soldiers need support before, during, and after their service," Kreider explains. "There needs to be a time for soldiers to transition, become re-engaged within a community, and stay engaged in that community."

Tuesday, September 20, 2016

Early menopause: increased risk of coronary heart disease, cardiovascular disease mortality, all-cause mortality

In a study published online by JAMA Cardiology, Taulant Muka, M.D., Ph.D., of Erasmus University Medical Center, Rotterdam, the Netherlands, and colleagues evaluated the effect of age at onset of menopause and duration since onset of menopause on certain cardiovascular disease (CVD) outcomes and all-cause mortality.

As many as 10 percent of women experience natural menopause by the age of 45 years. If confirmed, an increased risk of CVD and all-cause mortality associated with premature and early-onset menopause could be an important factor affecting risk of disease and mortality among middle-aged and older women. To examine this issue, the researchers conducted a systematic review and meta-analysis of 32 studies (310,329 women) that met criteria for inclusion in the study.

Outcomes were compared between women who experienced menopause younger than 45 years and women 45 years or older at onset. The researchers found that overall, women who experienced premature or early-onset menopause appeared to have a greater risk of coronary heart disease (CHD), CVD mortality, and all-cause mortality but no association with stroke risk. Women between 50 and 54 years at onset of menopause had a decreased risk of fatal CHD compared with women younger than 50 years at onset.

Time since onset of menopause in relation to risk of developing intermediate cardiovascular traits or CVD outcomes was reported in 4 observational studies with inconsistent results.

"The findings of this review indicate a higher risk of CHD, cardiovascular mortality, and overall mortality in women who experience premature or early-onset menopause when younger than 45 years. However, this review also highlights important gaps in the existing literature and calls for further research to reliably establish whether cardiovascular risk varies in relation to the time since onset of menopause and the mechanisms leading early menopause to cardiovascular outcomes and mortality," the authors write.

Monday, September 19, 2016

A diet that includes plenty of green, leafy vegetables may lower the risk of glaucoma

A healthy lifestyle, consisting of balanced nutrition, moderate exercise, and appropriate rest is an important part of your overall health and well-being and can help prevent illness too.

The best way to ensure that you're getting all of your essential vitamins and minerals is to eat a balanced diet that includes fruits and vegetables -- they are a primary source of carotenoids, which can have overall benefits for vision health. Certain fruits and vegetables with higher vitamin A and C content have been shown to reduce glaucoma risk as well. Some of the most helpful fruits and vegetables for healthy vision are: collard greens, cabbage, kale, spinach, Brussels sprouts, celery, carrots, peaches, radishes, green beans, and beets.

Because oxidative stress is associated with damage to the optic nerve in glaucoma, antioxidants may help to prevent further injury. Dietary sources of antioxidants include pomegranate, acai berries, cranberries, dark chocolate, black and green tea, bilberry, lycopene (from tomato products), dark green leafy vegetables like kale and spinach, and flax seeds.

Any specific nutritional deficiencies in your diet can be addressed with supplements that include Vitamins A, B-complex, C, and E as well as the minerals Magnesium, Calcium and Zinc. However, there is no convincing data that vitamin supplements help to prevent glaucoma. I recommend that patients take a general multivitamin if they are uncertain whether their daily nutritional needs are met.

While good nutrition plays a role in disease prevention and overall health, it is not a treatment for glaucoma. Certain herbs such as ginkgo and bilberry may even increase the risk of bleeding with glaucoma surgery. Given the breadth of nutritional supplements available over-the-counter, it is important to discuss with your eye doctor all prescription, herbal, vitamin, mineral, and over-the-counter remedies you currently take. Talk to your doctor about any other questions related to glaucoma and your diet, exercise, and lifestyle choices.

Saturday, September 17, 2016

Laughter + physical activity could improve older adults' mental health, aerobic endurance

Incorporating laughter into a physical activity program that is focused on strength, balance and flexibility could improve older adults' mental health, aerobic endurance and confidence in their ability to exercise, according to a study led by Georgia State University.

In this study, older adults residing in four assisted-living facilities participated in a moderate-intensity group exercise program called LaughActive that incorporates playful simulated laughter into a strength, balance and flexibility workout. In simulated laughter exercises, participants initially choose to laugh and go through the motions of laughing. The exercises facilitate eye contact and playful behaviors with other participants, which generally transition the laughter from simulated to genuine.

Simulated laughter techniques are based on knowledge that the body cannot distinguish between genuine laughter that might result from humor and laughter that is self-initiated as bodily exercise. Both forms of laughter elicit health benefits, researchers said.

For six weeks, study participants attended two 45-minute physical activity sessions per week that included eight to 10 laughter exercises lasting 30 to 60 seconds each. A laughter exercise was typically incorporated into the workout routine after every two to four strength, balance and flexibility exercises. Because laughter is scientifically demonstrated to strengthen and relax muscles, the laughter exercises often involved physicality in the muscles being worked in strength, balance and flexibility exercises to prepare the body for exercise and help it recover.

The study found significant improvements among participants in mental health, aerobic endurance and outcome expectations for exercise (for example, perceived benefit of exercise participation), based on assessments completed by the participants. When surveyed about their satisfaction with the program, 96.2 percent found laughter to be an enjoyable addition to a traditional exercise program, 88.9 percent said laughter helped make exercise more accessible and 88.9 percent reported the program enhanced their motivation to participate in other exercise classes or activities. The findings are published in the journal The Gerontologist.

Despite the health benefits of physical activity and the risks of physical inactivity, many adults don't engage in sufficient physical activity to achieve health benefits. Maintaining the motivation to adhere to regular physical activity is a challenge for many older adults. Adults should participate in a minimum of 30 minutes of physical activity at least five days per week to achieve desirable health outcomes, according to the U.S. Department of Health and Human Services' 2008 Physical Activity Guidelines.

These health benefits include lower mortality and a reduced risk of a number of chronic conditions, including coronary heart disease, high blood pressure, stroke, type 2 diabetes, metabolic syndrome, osteoporosis, colon cancer, breast cancer, anxiety and depression. Regular physical activity also reduces the impact of age-related declines in aerobic endurance, the incidence of falls and hip fracture and the degenerative loss of muscle mass, quality and strength. All of these benefits are crucial in older adults maintaining their ability to perform activities of daily living.

The pleasant associations with laughter may add enjoyment to an exercise program and keep older adults motivated to work out.

"The combination of laughter and exercise may influence older adults to begin exercising and to stick with the program," said Celeste Greene, lead author of the study and a master's degree graduate from Georgia State's Gerontology Institute. "We want to help older adults have a positive experience with exercise, so we developed a physical activity program that specifically targets exercise enjoyment through laughter. Laughter is an enjoyable activity and it carries with it so many health benefits, so we incorporated intentional laughter into this program to put the fun in fitness for older adults."

Simulated laughter may be an ideal way for older adults with functional or cognitive impairment to achieve the health benefits of laughter, which include improved physiological and psychological functioning. Participants simply choose to laugh and initiate laughter as bodily exercise. There is no need to rely on cognitive skills to "get the joke" because there is no joke. Further research is needed to better understand the underlying mechanisms of laughter, the effect of different levels of exposure to laughter and its associated health benefits.

This research is one of few studies to evaluate the potential of simulated laughter in improving health outcomes among older adults, and it's the first evaluation of a dedicated physical activity program that incorporated simulated laughter, said Dr. Jennifer Craft Morgan, second author of the study and Greene's thesis adviser.

Lowering systolic blood pressure would save more than 100,000 lives per year

Intensive treatment to lower systolic (top number) blood pressure to below 120 would save more than 100,000 lives per year in the United States, according to a study led by Loyola University Chicago researcher Holly Kramer, MD, MPH.

Two thirds of the lives saved would be men and two thirds would be aged 75 or older, according to the study, which was presented at the American Heart Association's Council on Hypertension 2016 Scientific Sessions. Current guidelines recommend keeping systolic blood pressure below 140 mm Hg.

"When the treatment goal was lowered to a maximum of 120 mm HG, there was a huge reduction in mortality," said Dr. Kramer, the study's first author. "Few other medical interventions have such a large effect."

Dr. Kramer is an associate professor in the Department of Public Health Sciences and in the Division of Nephrology and Hypertension in the Department of Medicine of Loyola University Chicago Stritch School of Medicine.

To determine whether intensive treatment to lower systolic blood pressure could alter mortality, Dr. Kramer and colleagues applied findings from a multicenter study called SPRINT to the U.S. adult population. (SPRINT stands for Systolic Blood Pressure Intervention Trial.)

Loyola University Medical Center was among the centers that enrolled patients in the SPRINT trial, which included more than 9,350 adults ages 50 and older who had high blood pressure and were at high risk for cardiovascular disease. The SPRINT trial found there was a 27 percent reduction in mortality from all causes when systolic blood pressure was lowered to below 120 mm Hg, compared to the standard care of lowering blood pressure to below 140 mm Hg.

While saving lives, an intensive blood pressure regimen also would cause serious side effects. The study by Dr. Kramer and colleagues estimated that approximately 55,500 more episodes of low blood pressure, 33,300 more episodes of fainting and 44,400 additional electrolyte disorders would occur annually with implementation of intensive systolic blood pressure lowering in U.S. adults who meet SPRINT criteria. Most of these effects would not be expected to have lasting consequences and would be reversible by lowering blood pressure medications, Dr. Kramer said.

High blood pressure, or hypertension, is a leading risk factor for heart disease, stroke, kidney failure and other health problems. An estimated 1 in 3 people in the United States has high blood pressure. Blood pressure is measured in millimeters of mercury (mm Hg). Systolic blood pressure refers to the pressure in the arteries when the heart beats. The bottom number, diastolic, refers to the pressure between beats.

In the SPRINT study, patients who were treated to achieve a standard target of less than 140 mm Hg received an average of two different blood pressure medications. The group treated to achieve a target of less than 120 mm Hg received an average of three medications. (The study excluded certain patients, including diabetics and smokers.)

Using data from the National Health & Nutrition Examination Survey, researchers determined that more than 18.1 million American adults met the criteria of patients enrolled in the SPRINT trial. Dr. Kramer and colleagues estimated that, among these 18.1 million adults, fully implementing an intensive regimen to lower systolic blood pressure below 120 mm Hg would prevent approximately 107,500 deaths per year.

Survival from localised prostate cancer extremely high, 99% over 10 years, irrespective of the treatment assigned

Active monitoring is as effective as surgery and radiotherapy, in terms of survival at 10 years, reports the largest study of its kind, funded by the National Institute for Health Research (NIHR).

Results published in New England Journal of Medicine show that all three treatments result in similar, and very low, rates of death from prostate cancer. Surgery and radiotherapy reduce the risk of cancer progression over time compared with active monitoring, but cause more unpleasant side-effects.

The ProtecT trial, led by researchers at the Universities of Oxford and Bristol in nine UK centres, is the first trial to evaluate the effectiveness, cost-effectiveness and acceptability of three major treatment options: active monitoring, surgery (radical prostatectomy) and radiotherapy for men with localised prostate cancer.

Chief investigator Professor Freddie Hamdy from the University of Oxford, said: 'What we have learnt from this study so far is that prostate cancer detected by PSA blood test grows very slowly, and very few men die of it when followed up over a period of 10 years, -- around 1% -- irrespective of the treatment assigned. This is considerably lower than anticipated when we started the study.

'However, treating the disease radically, when found, reduces the number of men who develop spread of prostate cancer, but we do not know yet whether this will make a difference to them living longer or better, and we have been unable to determine reliably which disease is lethal, and which can be left alone.'

Between 1999 and 2009, 82,429 men aged 50-69 across the UK were tested and 1,643 diagnosed with localised prostate cancer agreed to be randomised to active monitoring (545), radical prostatectomy (553) or radical radiotherapy (545). The research team measured mortality rates at 10 years, cancer progression and spread, and the impact of treatments reported by men.

The research team found that survival from localised prostate cancer was extremely high, at approximately 99%, irrespective of the treatment assigned.

The rate of cancer progression and spread was reduced by more than half in men in the surgery and radiotherapy groups, compared with active monitoring; cancer progression occurred in one in five in the active monitoring group, as opposed to less than one in 10 in the surgery and radiotherapy groups. However, surgery and radiotherapy caused unpleasant side-effects, particularly in the first year after treatment.

There was some recovery from side-effects over two to three years. But after six years, twice as many men in the surgery group still experienced urine leakage and problems with their sex life, in comparison with those in the active monitoring and radiotherapy groups. Radiotherapy caused more bowel problems than surgery or active monitoring.

Overall quality of life, including anxiety and depression, were not affected by any treatment at any time. Half of the men stayed on active monitoring over the 10-year period and avoided treatment side effects.

'This is the first time radiotherapy, surgery and active monitoring treatments for prostate cancer have been compared directly. The results provide patients and clinicians with detailed information about the effects and impacts of each treatment so that they can make an informed decision about which treatment to have,' said co-investigator Professor Jenny Donovan, from the University of Bristol. 'Each treatment has different impacts and effects, and we need longer follow up to see how those balance out over the next 10 years.'

Professor David Neal, a co-investigator from the University of Oxford, said: 'Interestingly, we saw that disease spread was reduced by half in men who were assigned to radical treatment, but no difference in survival outcomes with either surgery or radiotherapy, and no progression of the disease in three quarters of the men in the active monitoring treatment group, over the 10 years. We need to continue to study these men to find out whether prevention of cancer progression by surgery or radiotherapy leads to better cancer control and survival in the longer term.'

Professor Freddie Hamdy added: 'Longer follow-up is now required to determine the 'trade-off' that patients need to make between cancer outcomes and quality of life, and further research to understand how we can distinguish lethal from non-lethal disease.

'It is important that this research was conducted and that wouldn't be possible without the NIHR and its infrastructure enabling large scale randomised clinical trials to be carried out across the NHS.'

The findings of the study will play a key part in the decision to screen for prostate cancer, and are being used as part of a study investigating the effectiveness and cost-effectiveness of prostate-specific antigen (PSA) testing for screening for prostate cancer, the CAP study.

Anne Mackie, Director at Public Health England Screening said: 'The National Screening Committee has been following the ProtecT trial closely. The results of this study will provide men and their doctors with key information needed to manage localised prostate cancer.'

Cognitive function improves with aerobic exercise, but not for people exposed to high levels of mercury before birth

Cognitive function improves with aerobic exercise, but not for people exposed to high levels of mercury before birth, according to research funded by the National Institute of Environmental Health Sciences (NIEHS), part of the National Institutes of Health. Adults with high prenatal exposure to methylmercury, which mainly comes from maternal consumption of fish with high mercury levels, did not experience the faster cognitive processing and better short term memory benefits of exercise that were seen in those with low prenatal methylmercury exposures.

This is one of the first studies to examine how methylmercury exposure in the womb may affect cognitive function in adults. Mercury comes from industrial pollution in the air that falls into the water, where it turns into methylmercury and accumulates in fish. The scientists, based at the Harvard T.H. Chan School of Public Health, suspect that prenatal exposure to methylmercury, known to have toxic effects on the developing brain and nervous system, may limit the ability of nervous system tissues to grow and develop in response to increased aerobic fitness.

"We know that neurodevelopment is a delicate process that is especially sensitive to methylmercury and other environmental toxins, but we are still discovering the lifelong ripple effects of these exposures," said Gwen Collman, Ph.D., director of the NIEHS Division of Extramural Research and Training. "This research points to adult cognitive function as a new area of concern.."

The 197 study participants are from the Faroe Islands, 200 miles north of England, where fish is a major component of the diet. Their health has been followed since they were in the womb in the late 1980s. At age 22, this subset of the original 1,022 participants took part in a follow-up exam that included estimating the participants' VO2 max, or the rate at which they can use oxygen, which increases with aerobic fitness. Also, a range of cognitive tests were performed related to short-term memory, verbal comprehension and knowledge, psychomotor speed, visual processing, long-term storage and retrieval, and cognitive processing speed.

Overall, the researchers found that higher VO2 max values were associated with better neurocognitive function, as expected based on prior research. Cognitive efficiency, which included cognitive processing speed and short term memory, benefitted the most from increased VO2 max.

But when the researchers divided the participants into two groups based on the methylmercury levels in their mothers while they were pregnant, they found that these benefits were confined to the group with the lowest exposure. Participants with prenatal methylmercury levels in the bottom 67 percent, or levels of less than 35 micrograms per liter in umbilical cord blood, still demonstrated better cognitive efficiency with higher VO2 max. However, for participants with higher methylmercury levels, cognitive function did not improve as VO2 max increased.

"We know that aerobic exercise is an important part of a healthy lifestyle, but these findings suggest that early-life exposure to pollutants may reduce the potential benefits," added Collman. "We need to pay special attention to the environment we create for pregnant moms and babies."

The U.S. Food and Drug Administration recommends that children and women of childbearing age eat two to three weekly servings of fish low in mercury as part of a healthy diet. Low mercury fish include salmon, shrimp, pollock, canned light tuna, tilapia, catfish, and cod. Four types of fish should be avoided because of typically high mercury levels -- tilefish from the Gulf of Mexico, shark, swordfish, and king mackerel.

The findings were published Sept. 9 in the journal Environmental Health Perspectives. In addition to NIH funding, the research was supported by the Danish Council for Strategic Research, Programme Commission on Health, Food, and Welfare.

A diet high in calcium and low in lactose may reduce the risk of ovarian cancer in African-American women

Research from Rutgers Cancer Institute of New Jersey and and other U.S. health and academic institutions shows a diet high in calcium and low in lactose may reduce the risk of ovarian cancer in African-American women. The work, which appears in the latest edition of the British Journal of Cancer, also found sun exposure in the summer months may reduce the risk of developing the disease in this population.

Ovarian cancer is the fifth leading cause of cancer death among women in the U.S., according to the National Cancer Institute. And while five-year survival rates for this disease have improved in Caucasian women from 35 percent in 1975-77 to 46 percent, rates decreased in African-American females during this period from 42 to 38 percent (Howlader, et al., 2005). Previous studies have revealed positive associations between dairy consumption or lactose intake with the risk of ovarian cancer, and other studies have not. Given the populations in these previous works were primarily of European ancestry, Rutgers Cancer Institute investigators and their collaborators wanted to focus on the African-American population.

The associations were evaluated among participants in the African-American Cancer Epidemiology Study, which is an ongoing population-based case-control study of ovarian cancer in African-American women in 11 states including New Jersey. African-American females aged 20 to 79 years old with newly diagnosed invasive epithelial ovarian cancer were deemed eligible case participants. Healthy control participants were self-identified African-American women and were selected using random-digit phone dialing. Eligible for analysis were 490 case participants and 656 control participants who completed a phone questionnaire regarding various lifestyle factors including how many dairy products they consumed each week and how much time they spent in the sun.

Investigators found that both lactose intake and consumption of whole milk were significantly associated with an increased risk of ovarian cancer risk in African-American women, while skim and low-fat milk were not. No association was found for cheese or yogurt products. Calcium intake, whether through food and/or supplement, was associated with a decreased risk of disease. While researchers found no association between dietary and supplemental vitamin D intake and ovarian cancer risk, they noticed that fewer than 20 percent of African-American women in the study achieved the recommended daily vitamin D intake of at least 600 IU (or 800 IU if older than 70 years of age).

Results also showed that increased sun exposure may reduce ovarian cancer risk in this population. While separate research (Holick, 2011) shows Caucasian women need only five to 15 minutes of mid-day sun during spring, summer and fall to achieve an adequate amount of vitamin D production, African-American women need exposure five to 10 times longer due to their skin pigment. The current study's lead author, Rutgers Cancer Institute researcher Bo "Bonnie" Qin, PhD, is aware of the risks for skin cancer. "Because the benefits of increased sun exposure in African-American women may be offset by an increased risk of skin cancer, a combination of moderate sun exposure coupled with sufficient vitamin D intake from diet and supplements may be a safer solution for adequate vitamin D levels," notes Dr. Qin.

The study's senior author Elisa Bandera, MD, PhD, who is co-leader of the Cancer Prevention and Control Program at Rutgers Cancer Institute, notes this research adds to the scarce literature on causes of ovarian cancer in the African-American population. "Given that we were able to recruit a large sample of healthy African-American women and those with ovarian cancer from various geographic regions with diverse socioeconomic and lifestyle characteristics, we are able to generalize our findings to the African-American population," says Dr. Bandera, who is also a professor of medicine at Rutgers Robert Wood Johnson Medical School and a professor of epidemiology at Rutgers School of Public Health. "Considering there is no effective screening tool for ovarian cancer and that African-American patients have poor survival rates with this disease, prevention through lifestyle or dietary modifications is critical."

Monday, September 12, 2016

Midlife physical activity is associated with better cognition in old age

A long-term follow-up study of 3050 twins from the Finnish Twin Cohort has shown that midlife, moderately vigorous physical activity is associated with better cognition at old age. The association was statistically independent of midlife hypertension, smoking, education level, sex, obesity and binge drinking. "his suggests that the beneficial influence of physical activity on the brain and cognition is not solely based on decreasing vascular risk factors", says researcher Paula Iso-Markku from the University of Helsinki.

The association was studied first in all individuals of the cohort, and then by comparing later cognition in pairs where one twin was more physically active than the other.

Increasing the volume of physical activity was not, however, associated with increased memory-protecting benefits. Instead, quite a moderate amount of physical activity was found to be sufficient for memory-protecting benefits, and only the most inactive group of twins stood out with a significantly higher risk for cognitive impairment.

Overall, the study shows that moderately vigorous physical activity, meaning more strenuous than walking, is associated with better cognition after an average of 25 years. "This finding is in accordance with earlier animal model studies, which have shown that physical activity increases the amount of growth factors in the brain and improves synaptic plasticity", states Professor Urho Kujala from the University of Jyväskylä.

The prevalence of dementia has increased with aging populations both in Finland and globally. Although the incidence of dementia seems to have decreased in less senior generations, the total prevalence of dementia is still expected to rise. No cure for dementia exists, but during the last decade research has produced an abundance of new information on dementia prevention. The traditional vascular risk factors (elevated blood pressure, hypercholesterolemia, obesity, diabetes and lack of exercise) have also been associated with dementia risk.

"However, few long-term, high-quality, follow-up studies on physical activity and cognition have been published, and it has remained unclear what type and amount of exercise is needed to safeguard cognition", Iso-Markku says.

The study, published in the Journal of Alzheimer's Disease, was conducted by scientists at the universities of Helsinki, Jyväskylä and Turku. The twins provided information on physical activity through questionnaire surveys from 1975 and 1981 (mean age in 1981: 49 years), while cognition was assessed by validated telephone interviews conducted between 1999 and 2015.

Eating your greens could enhance sport performance

Nitrate supplementation in conjunction with Sprint Interval Training in low oxygen conditions could enhance sport performance a study has found.

Researchers from the University of Leuven in Belgium carried out a study with twenty-seven moderately trained participants. These were given nitrate supplements ahead of Sprint Interval Training (SIT), which took the form of short but intense cycling sessions three times a week.

Nitrate is commonly found in diets rich in leafy green foods, like spinach and is important for the functioning of the human body, especially during exercising.

To assess differences in performance in different conditions, the study included workouts in normal oxygen conditions and in hypoxia conditions, which are low oxygen levels such as those found in high altitudes.

The observations published in Frontiers in Physiology were unexpected: after only five weeks, the muscle fiber composition changed with the enhanced nitrate intake when training in low oxygen conditions.

"This is probably the first study to demonstrate that a simple nutritional supplementation strategy, i.e. oral nitrate intake, can impact on training-induced changes in muscle fiber composition;" stated Professor Peter Hespel from the Athletic Performance Center at the University of Leuven.

For athletes participating in sports competitions which require energy production in conditions with limited amounts of oxygen, this study is particularly interesting. In fact, exercising at high altitudes has become a training strategy for many athletes, albeit the uncertainties about such methods.

In these conditions, performing intense workouts requires high input of fast-oxidative muscle fibers to sustain the power. Enhancing these muscle fiber types through nutritional intake could very well boost the performance in this type of events.

However, this remains a question mark for the time being. "Whether this increase in fast-oxidative muscle fibers eventually can also enhance exercise performance remains to be established;" said Professor Hespel.

He cautioned: "consistent nitrate intake in conjunction with training must not be recommended until the safety of chronic high-dose nitrate intake in humans has been clearly demonstrated".

In times where athletes push the limits of their bodies and thrive for ever greater performances, this is clearly only the beginning of the research into how athletes can improve their competitive edge through dietary supplements. Looking to the future, Professor Hespel suggested: "it would now be interesting to investigate whether addition of nitrate-rich vegetables to the normal daily sports diet of athletes could facilitate training-induced muscle fiber type transitions and maybe in the long term also exercise performance".

Weight loss drug could particularly benefit 'emotional eaters'

A weight-loss drug dampened the response to food cues in regions of the brain associated with attention and emotion, leading to decreases in caloric intake, weight and body mass index (BMI), a team led by scientists at Beth Israel Deaconess Medical Center (BIDMC) reported. In the first study of the drug lorcaserin in the human brain, the research revealed the mechanism underlying the drug's efficacy and provides insight into which individuals may benefit most from the medication. The paper was published today in the journal Diabetes, the journal of the American Diabetes Association.

"Human feeding behaviors involve areas of the brain responsible for cognitive control and decision-making," said Christos S. Mantzoros, MD, Director of the Human Nutrition Unit in the Division of Endocrinology, Diabetes and Metabolism at BIDMC and Professor of Medicine at Harvard Medical School. "We wanted to find out if lorcaserin was acting on these brain regions and, if so, where and how. One-third of the U.S. population is obese, and another one-third is overweight. This is a huge burden on individuals and the health care system. In addition, it increases the risk of diabetes, cardiovascular disease and many types of cancer. We need to continue to develop safe and effective therapies to combat this epidemic."

Approved by the FDA in 2012, the generic drug lorcaserin is a medication prescribed for obese or overweight adults who also have weight-related health complications such as diabetes. Several studies have shown the drug helps about half of the people who take it lose more than 5 percent of their body mass within a year, but there's a great deal of variability in individual results, and the mechanism underlying its effect was previously unknown.

To determine how the drug works in the human brain, Mantzoros and colleagues observed 48 obese men and women - half taking the drug, half taking a placebo - over the course of a four-week experiment. Participants came into the clinic on four occasions for blood work, physical exams, measurements and weight-loss counseling with a registered dietician. They were also expected to keep records of the food they ate during the study.

On three visits - before receiving any medication (Week 0), after a week of medication (Week 1), and after four weeks of medication (Week 4) - exams were followed by two brain scans: one after the patients had fasted for at least 12 hours, the other after they had eaten a meal. The scans were taken using functional magnetic resonance imaging (fMRI) to measure changes in blood flow in an active brain, which suggests which regions play a role during a given task. During each scan, participants were shown 150 images of foods generally considered highly desirable, such as cake and onion rings; foods generally considered less desirable like vegetables; and nonfood items like rocks and trees.

At Week 1, the fMRI scans in the fasting state revealed that people taking the drug showed decreased brain activity in response to images of highly desirable foods in the attention-related parietal and visual cortices. At Week 4, the lorcaserin group in the fed state showed less activity in the parietal cortex - which is responsible for integrating sensory information - when looking at any of the food images.

The data also revealed that subjects who had the strongest brain responses to food prior to taking lorcaserin saw the most success with the weight-loss medication.

"Decreases in caloric intake, weight, and BMI were linked to strong responses to food cues in the areas of the brain related to emotion, pleasure and attention prior to taking the weight-loss drug, which suggests that lorcaserin could prove to be of particular benefit to 'emotional eaters,' " Mantzoros said.

Lorcaserin targets only a very specific serotonin receptor (known as 5-HT2c), shown in animal studies to play a role in abnormal food consumption. A previous generation of weight loss drugs was linked to this receptor, but because their scope was broader, those products also had dire cardiac side effects including pulmonary hypertension and valve problems. Lorcaserin could produce weight loss without these cardiac risks, the authors noted.

"In addition, the different mechanism of action in comparison to other drugs for obesity creates an opportunity for combination drugs for the treatment of obesity," Mantzoros said. "This might create more powerful solutions and is something that remains to be explored."

The U.S. Food and Drug Administration (FDA) has approved 5 weight loss drugs (orlistat, lorcaserin, naltrexone-bupropion, phentermine-topiramate, and liraglutide) for long-term use in obese (body mass index [BMI] > 30) or overweight (BMI >27) individuals with at least 1 weight-associated condition (type 2 diabetes, hypertension, hyperlipidemia). The researchers found that a median 23 percent of placebo participants had at least 5 percent weight loss vs 75 percent of participants taking phentermine-topiramate, 63 percent of participants taking liraglutide, 55 percent taking naltrexone-bupropion, 49 percent taking lorcaserin, and 44 percent taking orlistat. All active agents were associated with significant excess weight loss compared with placebo at 1 year: phentermine-topiramate, 19.4 lbs.; liraglutide, 11.7 lbs.; naltrexone-bupropion, 11 lbs.; lorcaserin, 7.1 lbs.; and orlistat, 5.7 lbs. Compared with placebo, liraglutide and naltrexone-bupropion were associated with the highest odds of adverse event-related treatment discontinuation.


Tuesday, September 6, 2016

Higher thyroid hormone levels linked to sudden cardiac death

Risk of death from a sudden loss of heart function was significantly greater in patients with thyroid hormone levels at the higher end of normal range, compared to patients with levels at the lower end, according to new research in the American Heart Association's journal Circulation.

Sudden cardiac death, occurs when the heart's normal electrical rhythm malfunctions, causing the heart to stop beating. According to a 2012 Circulation study, more than half of all cardiovascular deaths stem from sudden cardiac death, and in many instances no previous symptoms of heart disease were apparent.

"Currently, we do not have a good way to predict sudden cardiac death in the general population," said Layal Chaker, M.D., M.Sc., study lead author and doctoral candidate and research fellow in endocrinology and epidemiology at Erasmus University Medical Center Rotterdam in the Netherlands. "Thus identifying additional risk factors is crucial. Our results indicate that thyroid hormone levels may be useful for assessing risk to prevent sudden cardiac death."

Thyroid hormone is made in the thyroid gland and circulates in the blood to help regulate nearly all of the body's organs, including the heart. Although the link between abnormal levels of thyroid hormone and cardiovascular disease is well established, the hormone's relationship with sudden cardiac death is unclear.

Researchers analyzed 10,318 patients in the Rotterdam Study, which is a long-term investigation of heart and other chronic disease among the middle-aged and elderly in the Netherlands. Participants' average age was 65, more than half were women, and nearly all were Caucasian.

Researchers linked the association of thyroid-stimulating hormone and free thyroxine thyroid hormone levels in blood samples with sudden cardiac deaths listed on medical records and death certificates. During an average follow-up of nine years they found:

Participants with free thyroxine hormone levels at the high end of the normal range were 2.5 times more likely to die of sudden cardiac death, compared to patients with levels at the lower end.

  • The ten-year risk of sudden cardiac death was four times greater among patients with higher free thyroxine levels compared to those with lower levels -- 4 percent versus 1 percent.
  • The increased risk persisted even after controlling for other risk factors, such as high cholesterol and high blood pressure.
  • 261 cases of sudden cardiac death occurred.
"We know that a considerable proportion of patients on thyroid hormone replacement therapy are over-treated and so have high blood levels of thyroid hormone," Chaker said. "Our study suggests more caution is warranted in the treatment of thyroid hormone replacement. Replacement therapy is often aimed at the high normal range which carries a risk of overtreatment."

Researchers suggest further research is warranted because factors other than thyroid hormone levels could have contributed to the sudden cardiac deaths. The study also relied on a one-time test, and thyroid hormone levels could have changed throughout the course of the study. And, since most participants were Caucasian, the findings also may not apply to people of other races.

Is sex in later years good for your health?

Having sex frequently - and enjoying it - puts older men at higher risk for heart attacks and other cardiovascular problems. For older women, however, good sex may actually lower the risk of hypertension.

That's according to the first large-scale study of how sex affects heart health in later life. The federally funded research, led by a Michigan State University scholar, is slated to be published online Sept. 6 in the Journal of Health and Social Behavior.

"These findings challenge the widely held assumption that sex brings uniform health benefits to everyone," said Hui Liu, MSU associate professor of sociology.

Liu and colleagues analyzed survey data from 2,204 people in the National Social Life, Health and Aging Project. Participants were aged 57-85 when the first wave of data was collected in 2005-06; another round of data was collected five years later. Cardiovascular risk was measured as hypertension, rapid heart rate, elevated C-reactive protein and general cardiovascular events: heart attack, heart failure and stroke.

Older men who had sex once a week or more were much more likely to experience cardiovascular events five years later than men who were sexually inactive, the study found. This risk was not found among older women.

"Strikingly, we find that having sex once a week or more puts older men at a risk for experiencing cardiovascular events that is almost two times greater than older men who are sexually inactive," said Liu. "Moreover, older men who found sex with their partner extremely pleasurable or satisfying had higher risk of cardiovascular events than men who did not feel so."

She said the findings suggest the strain and demands from a sexual relationship may be more relevant for men as they get older, become increasingly frail and suffer more sexual problems.

"Because older men have more difficulties reaching orgasm for medical or emotional reasons than do their younger counterparts, they may exert themselves to a greater degree of exhaustion and create more stress on their cardiovascular system in order to achieve climax."

Testosterone levels and the use of medication to improve sexual function may also play a role. "Although scientific evidence is still rare," Liu said, "it is likely that such sexual medication or supplements have negative effects on older men's cardiovascular health."

Ultimately, while moderate amounts of sex may promote health among older men, having sex too frequently or too enjoyably may be a risk factor for cardiovascular problems, Liu said. "Physicians should talk to older male patients about potential risks of high levels of sexual activity and perhaps screen those who frequently have sex for cardiovascular issues."

For women, it was a different story. Female participants who found sex to be extremely pleasurable or satisfying had lower risk of hypertension five years later than female participants who did not feel so.

"For women, we have good news: Good sexual quality may protect older women from cardiovascular risk in later life," Liu said.

Previous studies suggest that strong, deep and close relationship is an important source of social and emotional support, which may reduce stress and promote psychological well-being and, in turn, cardiovascular health.

"This may be more relevant to women than to men," Liu said, "because men in all relationships, regardless of quality, are more likely to receive support from their partner than are women. However, only women in good quality relationships may acquire such benefits from their partner."

Moreover, the female sexual hormone released during orgasm may also promote women's health, she said.

Research shows it may be time to abandon dreaded digital rectal exam

The dreaded finger exam to check for prostate cancer used to be a mainstay of check-ups for older men. With its value now in question, some doctors share the risks and benefits with their patients and let them decide. So, should they or shouldn't they?

"The evidence suggests that in most cases, it is time to abandon the digital rectal exam (DRE)," said Ryan Terlecki, M.D., a Wake Forest Baptist urologist who recently published an article on the topic in Current Medical Research and Opinion. "Our findings will likely be welcomed by patients and doctors alike."

Terlecki said the DRE, referred to by some urologists as a "clinical relic," subjects a large number of men to invasive, potentially uncomfortable examinations for relatively minimal gain. In addition, it may deter some men from undergoing any test for prostate cancer.

The issue Terlecki's team explored was whether the DRE is needed when another more accurate test that measures prostate-specific antigen (PSA) in the blood is available. PSA is a protein that is often elevated in men with prostate cancer.

"Many practitioners continue to perform DRE in attempts to identify men with aggressive prostate cancer who could die from the disease," said Terlecki. "In the era of PSA testing, we wanted to explore whether it's time to abandon the digital exam."

To reach their conclusion, Terlecki's research team reviewed both medical literature and the results of a nationwide screening trial in which 38,340 men received annual DRE exams and PSA tests for three years. They were then followed for up to 13 years.

Of interest to Terlecki's team were the 5,064 men who had a normal PSA test but an "abnormal" DRE. Only 2 percent of these men had what is known as clinically relevant prostate cancer, which means it may need to be monitored or treated.

"The DRE does capture an additional small population of men with significant prostate cancer, but it also unnecessarily subjects a large number of men to the test," he said.

Until 2012, men over 50 (age 40 for African-Americans) were urged to have both DRE and PSA tests annually. That was before the United States Preventive Services Task Forces recommended against routine PSA testing because it could lead to over-treatment of slow-growing, non-harmful tumors. The panel did not address DRE, which was the primary method of detecting prostate cancer prior to the blood test.

As a result of the task force's recommendation, there has been confusion and controversy about whether men should be screened for prostate cancer. Some organizations recommend against any screening and others recommend PSA screening, but only if men are counseled about the potential benefits and risks.

In previous studies, PSA had been shown to outperform DRE in detecting significant disease. The current analysis confirmed that PSA is superior to DRE as an independent screen for prostate cancer. PSA testing detected 680 cases of significant cancer, compared to 317 cases for DRE.

"When PSA testing is used, the DRE rarely assists in diagnosing significant disease," said Terlecki. "In cases where PSA testing is used, the DRE should be abandoned in common clinical practice."

There is still a place for DRE testing for certain patients, Terlecki said. For example, a patient with abnormal PSA who is "on the fence" about having a biopsy, may feel more comfortable proceeding with the procedure if a DRE is also abnormal, he said.

Thursday, September 1, 2016

Intensive exercise. e.g.CrossFit: you need rest too

Are you a fitness enthusiast? If so, moderation and appropriate rest periods may be the key to healthier exercise, as consecutive CrossFit-style workouts could impair the immune system by affecting inflammatory proteins.

Current trends in the fitness industry have seen more people turning to high-intensity, constantly varied exercise programs to achieve their fitness goals. A huge array of exercise techniques including kettle bells, tyre flipping and ring pull-ups, coupled with celebrity endorsements and over 13,000 affiliated gyms make for the high-intensity fitness phenomenon that is CrossFit.

Advocates of CrossFit, which encompasses both cardiovascular and strength training, say that the varied and high-intensity nature of the workouts significantly enhances physique and overall fitness in a shorter time, and results are balanced across all the muscles of the body.

However, this high-intensity program has attracted controversy because of its emphasis on results rather than technique, which critics feel poses an unacceptable risk of injury, especially in inexperienced participants. CrossFit workouts often involve performing exercises in rapid succession, with little or no recovery time.

There is concern that this could lead to non-functional overreaching, where the balance between training and recovery is not correct, potentially causing fatigue, physiological stress and illness. There is also some evidence that repeated bouts of intense exercise on consecutive days can lead to white blood cell death or dysfunction.

A new study published in Frontiers in Physiology aimed to investigate if CrossFit training on two consecutive days could affect immune function, inflammatory proteins, metabolic stress and muscle power. The researchers assembled a group of experienced CrossFit participants, who had a minimum of six months of prior CrossFit training.

The participants underwent two consecutive days of high-intensity CrossFit-style workouts including Olympic lifting, power lifting and gymnastic exercises. They aimed to finish the workouts in the fastest time possible, without compromising on technique. The researchers assessed muscle power, levels of inflammatory cytokines and levels of metabolic markers, before, during and after the workouts.

They found that the workouts provoked a strong metabolic response and reduced the levels of anti-inflammatory cytokines, which are proteins produced by white blood cells that act to dampen inflammation. This means that the consecutive workouts were actually suppressing normal immune function.

However, the workouts did not adversely affect the muscle power of the participants. So what does this mean for CrossFit participants?

"For non-athlete subjects who want to improve their health and quality of life through Crossfit training, we recommend that they decrease their training volume after two consecutive days of high intensity training to prevent possible immunosuppression;" said Dr Ramires Tibana of the Catholic University of Brasilia, who is the lead author on the study.

This is particularly important for people recovering from illness, who may already have an impaired immune response, or at times of the year where viral illnesses are prevalent.

Dr Tibana also discussed other practical steps CrossFitters could take to enhance their recovery, including a rest day between exercise sessions: "A rest day is important for recovery for subsequent training sessions. Other alternative recovery techniques are regenerative training (with low intensity and volume), massage and cryotherapy."

Respect your recovery - check yourself before you wreck yourself.