Higher daily step count linked with lower all-cause mortality

Taking more steps each day is associated with a lower risk of death.NCI

In a new study, higher daily step counts were associated with lower mortality risk from all causes. The research team, which included investigators from the National Cancer Institute (NCI) and the National Institute on Aging (NIA), both parts of the National Institutes of Health, as well as from the Centers for Disease Control and Prevention, also found that the number of steps a person takes each day, but not the intensity of stepping, had a strong association with mortality.

The findings were published March 24, 2020, in the Journal of the American Medical Association.

“While we knew physical activity is good for you, we didn’t know how many steps per day you need to take to lower your mortality risk or whether stepping at a higher intensity makes a difference,” said Pedro Saint-Maurice, Ph.D., of NCI’s Division of Cancer Epidemiology and Genetics, first author of the study. “We wanted to investigate this question to provide new insights that could help people better understand the health implications of the step counts they get from fitness trackers and phone apps.”

Previous studies have been done on step counts and mortality. However, they were conducted primarily with older adults or among people with debilitating chronic conditions. This study tracked a representative sample of U.S. adults aged 40 and over; approximately 4,800 participants wore accelerometers for up to seven days between 2003 and 2006. The participants were then followed for mortality through 2015 via the National Death Index. The researchers calculated associations between mortality and step number and intensity after adjustment for demographic and behavioral risk factors, body mass index, and health status at the start of the study.

They found that, compared with taking 4,000 steps per day, a number considered to be low for adults, taking 8,000 steps per day was associated with a 51% lower risk for all-cause mortality (or death from all causes). Taking 12,000 steps per day was associated with a 65% lower risk compared with taking 4,000 steps. In contrast, the authors saw no association between step intensity and risk of death after accounting for the total number of steps taken per day.

“At NIA, we’ve long studied how exercise is important for older adults, and it’s good to see further evidence from a large study with a broad sample that the main thing is to get moving for better overall health as we age,” said Eric Shiroma, Ph.D., a co-author and NIA Intramural Research Program scientist.

In analyses by subgroups of participants, the authors found that higher step counts were associated with lower all-cause death rates among both men and women; among both younger and older adults; and among white, black, and Mexican-American adults. In secondary outcomes of the study, higher step counts were also associated with lower rates of death from cardiovascular disease and cancer.

Data collection was conducted through the CDC’s National Health and Nutrition Examination Survey (NHANES), a program of studies designed to assess a nationally representative sample of the health and nutritional status of adults and children in the United States.

The researchers were surprised they didn’t find an association between higher stepping intensity and all-cause mortality after adjusting for the total number of steps per day. Because few studies have investigated an association between mortality and intensity among adults going about their daily lives, the study authors wrote that future studies of walking intensity and mortality are warranted.

Although the study authors controlled for factors that could have affected the results, the study is observational and cannot prove causality. Nevertheless, their findings are consistent with current recommendations that adults should move more and sit less throughout the day. Adults who do any amount of physical activity gain some health benefits. For even greater health benefits, adults are recommended to get at least 150 minutes of moderate-intensity physical activity per week.

“Being physically active has many benefits, including reducing a person’s risk of obesity, heart disease, type 2 diabetes, and some cancers. And on a daily basis, it can help people feel better and sleep better,” said Janet Fulton, Ph.D., of CDC’s Division of Nutrition, Physical Activity, and Obesity. “CDC is working with communities and partners across the country, as part of the Active People, Healthy Nation initiative, to make it easier, safer, and more convenient for people to be active in their own communities." 

Isoflavones, in tofu and plant proteins, associated with lower heart disease risk

Eating tofu and foods that contain higher amounts of isoflavones was associated with a moderately lower risk of heart disease, especially for younger women and postmenopausal women not taking hormones, according to observational research published today in Circulation, the flagship journal of the American Heart Association.

Researchers at Harvard Medical School and Brigham and Women's Hospital analyzed data from more than 200,000 people who participated in three prospective health and nutrition studies; all participants were free of cancer and heart disease when the studies began. After eliminating a number of other factors known to increase heart risk, investigators found:

Consuming tofu, which is high in isoflavones, more than once a week was associated with a 18% lower risk of heart disease, compared to a 12% lower risk for those who ate tofu less than once a month; and

The favorable association with eating tofu regularly was found primarily in young women before menopause or postmenopausal women who were not taking hormones.

"Despite these findings, I don't think tofu is by any means a magic bullet," said lead study author Qi Sun, M.D., Sc.D., a researcher at Harvard's T.H. Chan School of Public Health in Boston. "Overall diet quality is still critical to consider, and tofu can be a very healthy component."

Sun noted that populations that traditionally consume isoflavone-rich diets including tofu, such as in China and Japan, have lower heart disease risk compared to populations that follow a largely meat-rich and vegetable-poor diet. However, the potential benefits of tofu and isoflavones as they relate to heart disease needs more research.

Tofu, which is soybean curd, and whole soybeans such as edamame are rich sources of isoflavones. Chickpeas, fava beans, pistachios, peanuts and other fruits and nuts are also high in isoflavones. Soymilk, on the other hand, tends to be highly processed and is often sweetened with sugar, Sun noted. This study found no significant association between soymilk consumption and lower heart disease risk.

"Other human trials and animal studies of isoflavones, tofu and cardiovascular risk markers have also indicated positive effects, so people with an elevated risk of developing heart disease should evaluate their diets," he said. "If their diet is packed with unhealthy foods, such as red meat, sugary beverages and refined carbohydrates, they should switch to healthier alternatives. Tofu and other isoflavone-rich, plant-based foods are excellent protein sources and alternatives to animal proteins."

In the study, researchers analyzed health data of more than 74,000 women from the Nurses' Health Study (NHS) from 1984 to 2012; approximately 94,000 women in the NHSII study between 1991 and 2013; and more than 42,000 men who participated in the Health Professionals Follow-Up Study from 1986 to 2012. All participants were free of cardiovascular disease and cancer at the beginning of each study. Dietary data was updated using patient surveys, conducted every two to four years. Data on heart disease was collected from medical records and other documents, while heart disease fatalities were identified from death certificates.

A total of 8,359 cases of heart disease were identified during 4,826,122 person-years of follow-up, which is the total number of years that study participants were free of heart disease and helps to measure how fast it occurs in a population.

Sun emphasized that the study should be interpreted with caution because their observations found a relationship but did not prove causality. Many other factors can influence the development of heart disease, including physical exercise, family history and a person's lifestyle habits. "For example, younger women who are more physically active and get more exercise tend to follow healthier, plant-based diets that may include more isoflavone-rich foods like tofu. Although we have controlled for these factors, caution is recommended when interpreting these results," said Sun.

In 2000, the U.S. Food and Drug Administration approved health claims that soy edibles protect against cardiovascular disease. However, since then, clinical trials and epidemiological studies have been inconclusive, and the agency is reconsidering its now twenty-year-old decision. The American Heart Association's 2006 Diet and Lifestyle Recommendations and a 2006 science advisory on soy protein, isoflavones and cardiovascular health

found minimal evidence that isoflavones convey any cardiovascular benefits and any protections provided by higher soy intake was likely due to higher levels of polyunsaturated fats, fiber, vitamins and minerals, and lower levels of saturated fat.

Higher daily step counts linked with lower blood pressure

The smart watches seen on the wrists of roughly 1 in 5 Americans could be more than just a fun gimmick but a potentially useful research tool to track habitual physical activity levels. People who took more steps daily, as tracked by their watch, had lower blood pressure on average than those taking fewer steps in a study presented at the American College of Cardiology's Annual Scientific Session Together with World Congress of Cardiology (ACC.20/WCC).

The research is part of the Framingham Heart Study, a project focusing on factors affecting heart disease that has been ongoing for more than 70 years. Researchers analyzed data from 638 study participants who were asked to wear an Apple Watch daily and record their blood pressure at home weekly. Over the course of the study, participants' average systolic blood pressure was 122 mm Hg and average diastolic blood pressure was 76 mm Hg, levels that are considered normal to slightly elevated according to the 2017 ACC/AHA High Blood Pressure in Adults guideline.

The study is one of the first to use commercially available wearable devices to track habitual physical activity in a large group of people in the context of daily life outside of a health care setting or research center.

"Measuring habitual physical activity in community-based settings in this way distinguishes our study from prior studies that have looked at either self-reported physical activity or used accelerometers to measure daily activity for only a short amount of time, usually about a week," said Mayank Sardana, MD, a clinical fellow at the University of California, San Francisco, and the study's lead author.

Although the study was observational and does not show cause and effect, the findings align with previous research suggesting that being more physically active can help lower blood pressure. After accounting for demographic factors, the study found participants' systolic blood pressure was about 0.45 points lower for every 1,000 daily steps taken, meaning that a person taking 10,000 steps daily would have a systolic blood pressure 2.25 points lower than a person taking just 5,000 steps daily, on average. Given that study participants had an average systolic blood pressure of 122 mm Hg, this amount could make the difference between blood pressure that is considered normal (less than 120 mm Hg) and elevated (120 mm Hg or higher).

"This study solidifies our understanding of the relationship between physical activity and blood pressure and raises the possibility that obesity or body mass index accounts for a lot of that relationship," Sardana said. "Going forward, it would be useful to look at how smart devices might be leveraged to promote physical activity, reduce the burden of obesity and potentially reduce blood pressure."

Researchers excluded data from the participants with less than 30 days of wear time to ensure participants were accustomed to wearing the watch. They also excluded data from the days on which the watch was worn for less than five hours to ensure the step counts reflected most of a person's daily movements. Over the course of about five months, participants averaged about 7,500 steps per day. Those with a higher daily step count had significantly lower systolic and diastolic blood pressure. In a secondary analysis, the researchers found the association between step count and blood pressure was no longer significant if BMI was taken into account, which suggests BMI might be a mediating factor in the relationship.

However, the study was not designed to discern whether BMI affects step count or the other way around.

"We should look to future studies to answer the question of directionality with a randomized trial or cohort intervention," Sardana said.

Sardana added that the electronic Framingham Heart Study cohort is the largest sample of participants developed leveraging the seminal Framingham Heart Study who are providing continuous data from smart devices for research. Their findings support the role of leveraging the data from wearable devices in epidemiology research to enhance the understanding of the relationship between cardiovascular risk factors and cardiovascular disease.

Nearly half of U.S. adults are estimated to have high blood pressure, and many don't know they have it. Over time, elevated blood pressure can weaken the heart, blood vessels, kidneys and other parts of the body.

Ritalin and similar medications cause brain to focus on benefits of work, not costs

Common assumption has long held that Ritalin, Adderall and similar drugs work by helping people focus.

Yet a new study from a team led in part by Brown University researchers shows that these medications -- usually prescribed to individuals diagnosed with attention deficit hyperactivity disorder, but often used by otherwise healthy people as a "study aid" -- actually work by directing the brain to fix its attention on the benefits, rather than the costs, of completing difficult tasks.

The study, published on Thursday, March 19 in the journal Science, marks the first time that scientists have examined precisely how stimulants such as Ritalin alter cognitive function. Their research could open opportunities for further studies to help medical professionals better understand how to identify and treat ADHD, depression, anxiety and other mental disorders.

"People tend to think, 'Ritalin and Adderall help me focus,'" said Michael Frank, the study's co-senior author and a professor of cognitive, linguistic and psychological sciences at Brown. "And they do, in some sense. But what this study shows is that they do so by increasing your cognitive motivation: Your perceived benefits of performing a demanding task are elevated, while the perceived costs are reduced. This effect is separate from any changes in actual ability."

According to Frank, stimulants such as Ritalin increase the amount of dopamine released in the striatum, a key region in the brain related to motivation, action and cognition. Previous research has shown that dopamine, a "chemical messenger" that ferries information between neurons, can greatly influence cognitive and physical behavior. Several past studies have found, for example, that both rodents and humans are more motivated to perform physically demanding tasks with higher dopamine.

What has remained unknown, though, is whether dopamine can have similar motivational effects on cognition -- and that's what a new collaborative project between Frank, Brown postdoctoral researcher Andrew Westbrook and Dutch neuropsychiatry scholar Roshan Cools set out to understand.

"We've known for a long time that when you give people these types of stimulants, you get enhanced performance," said Westbrook, the study's lead author. "But is that due to an increased ability, or is it due to increased motivation? We didn't know which of these two factors were contributing and to what degree."

Frank's team had previously developed mathematical models suggesting that dopamine alters the degree to which the striatum emphasizes the benefits, rather than the costs, of completing physical and mental actions. Drawing upon these models, Westbrook worked with Frank and Cools to develop an experiment that examined how stimulants that elevated dopamine levels affected people's mental cost-benefit analyses.

The researchers worked with 50 healthy women and men ages 18 to 43 in a lab at Radboud University in the Netherlands. First, they measured the natural dopamine levels in each subject's striatum using brain imaging technology. Then, they asked the subjects whether they would take part in a series of cognitively demanding tests, some easier and others more difficult, in exchange for certain amounts of money. Subjects who agreed to take the hardest tests stood to make the most money.

Each of the subjects completed the experiment three times -- once after taking a placebo; once after taking methylphenidate, the generic version of Ritalin; and once after taking sulpiride, an antipsychotic that elevates dopamine levels when taken in low doses and is often used to treat symptoms of schizophrenia and major depressive disorder at much higher doses. The researchers used a double-blind experiment design, where neither they nor the subjects knew which pill was being given to each subject.

The results largely matched Westbrook's computer-modeled predictions. Those with lower dopamine levels made decisions that indicated they were more focused on avoiding difficult cognitive work -- in other words, they were more sensitive to the potential costs of completing the task. Those with higher dopamine levels, on the other hand, made decisions that showed they were more sensitive to differences in the amount of money they could earn by choosing the harder test -- in other words, they focused more on the potential benefits. Westbrook said the latter held true whether the subjects' dopamine levels were naturally higher or whether they had been artificially elevated by medications.

Westbrook said the results support the idea that, medication or no medication, dopamine typically acts as a motivation regulator for human brains.

"The thoughts that pop into our head, and the amount of time we spend thinking about them, are regulated by this underlying cost-benefit decision-making system," Westbrook said. "Our brains have been honed to orient us toward the tasks that will have the greatest payoff and the least cost over time."

All of us have slightly different base levels of dopamine, said Frank, who is affiliated with the Carney Institute for Brain Science at Brown. Those who have lower levels tend to be more risk-averse, because they spend more time focusing on the potential costs of completing a difficult task. Those with higher levels tend to be more impulsive and active, because they focus more on the benefits.

No single dopamine level is inherently better than another, Frank said -- an active, high-dopamine person may take fulfilling, happiness-boosting risks but may also be more prone to injury; a risk-averse, low-dopamine person may avoid injuries and disappointments but may also miss out on adventures. And dopamine levels don't necessarily stay the same from one day to the next: They may decrease in response to danger or lack of sleep, and they may increase when people feel safe and supported.

In other words, Westbrook said, most people can trust natural dopamine levels to guide them toward the right decisions. Of course, previous experiments have made it clear that many people with particularly low dopamine levels -- including those who are diagnosed with depression or ADHD -- can benefit from dopamine-boosting stimulant medications. But he said those medications are never certain to improve the lives of those who are healthy and who choose to use them recreationally. Doing so could, in fact, lead some to make poorer decisions.

"When you raise dopamine in someone who already has a high dopamine level, every decision seems like it has benefit, which could distract from the real beneficial tasks," Westbrook said. "People might behave in ways that aren't consistent with their goals, like taking part in impulsive gambling or risky sex behaviors."

Westbrook and Frank hope their study helps future researchers and medical professionals better understand cognitive mechanisms, allowing them to identify connections between dopamine levels and disorders such as anxiety, depression, ADHD and schizophrenia.

"We want to know, what are the drivers of what changes cognitive ability and function?" Frank said. "Our research is focused on carving nature at its joints, so to speak -- disentangling neural and cognitive functions to understand people's different thought processes and evaluate what's best for their needs, whether it's therapy or medication."

Getting too little -- or too much -- sleep may be bad for the heart

Whether you like to burn the midnight oil to check emails or binge watch your favorite series, toss and turn or sleep until mid-morning, it seems the amount of sleep you get matters when it comes to your future vascular and heart health. Compared with people who slept for longer or shorter periods of time, those who reported sleeping seven or eight hours a night had significantly less evidence of stiffness in their arteries, indicating a lower chance of developing heart disease or suffering a stroke, according to research presented at the American College of Cardiology's Annual Scientific Session Together with World Congress of Cardiology (ACC.20/WCC).

Even after accounting for other known risk factors for heart disease or stroke, people who slept less than six hours or more than eight hours a night had significantly greater odds of having plaque buildup in the walls of their carotid arteries--a 54% and 39% increase, respectively--compared with those who got seven or eight hours of shut eye. The study adds to mounting evidence that sleep patterns, similar to diet and exercise, may play a defining role in someone's cardiovascular risk.

"The message, based on our findings, is 'sleep well, but not too well.' Getting too little sleep appears bad for your health but too much seems to be harmful as well," said Evangelos Oikonomou, MD, consultant cardiologist and the study's lead author. "Unlike other heart disease risk factors such as age or genetics, sleep habits can be adjusted, and even after taking into consideration the impact of established risk factors for atherosclerosis and cardiovascular diseases--for example age, gender, obesity, smoking, hypertension, diabetes, high blood pressure and even a history of coronary artery disease--both short and long sleeping duration may act as additional risk factors."

For this analysis, researchers assessed sleep patterns in 1,752 people living in the Corinthia region of Greece using a standard questionnaire that was fielded by a trained cardiologist, primary care provider or nurse. Participants were then divided into one of four groups based on self-reported sleep duration: normal (seven to eight hours a night), short sleep duration (six to seven hours a night), very short sleep duration (less than six hours a night) or long sleep duration (greater than eight hours a night). Participants represented a broad spectrum of the general public, including healthy people as well as those with cardiovascular risk factors and established heart disease, and most were from rural areas with less than 1,000-2,000 inhabitants. They ranged in age from 40 to 98 years, with a mean age of 64 years old.

At the time of the study, each participant also underwent ultrasound imaging to measure the thickness of the inner part of the arterial wall. Thickening of the arterial walls reflects plaque buildup and is associated with an increased risk of stroke and other cardiovascular events. Intima media thickness of >1.5 mm or protrusion >50% compared to nearby segments of the artery wall was defined as atherosclerotic plaque.

Researchers uncovered a U-shaped pattern between sleep duration and early indicators of atherosclerosis, which underscores the need for a balanced sleep pattern, Oikonomou said. Intima media thickness and plaque build-up in the artery walls was greater in both the shorter and longer sleep duration groups as compared to normal sleep duration.

"We don't fully understand the relationship between sleep and cardiovascular health. It could be that sympathetic nervous system withdrawal or a slowing [of this system] that occurs during sleep may act as a recovery phase for [usual] vascular and cardiac strain," Oikonomou said. "Moreover, short sleep duration may be associated with increased cardiovascular risk factors--for example, unhealthy diet, stress, being overweight or greater alcohol consumption--whereas longer sleep duration may be associated with a less active lifestyle pattern and lower physical activity."

Researchers said that adopting a balanced sleep pattern of six to eight hours nightly may be just what the doctor ordered.

"It seems that this amount of sleep may act as an additive cardioprotective factor among people living in modern western societies, and there can be other health benefits to getting sufficient and quality sleep," Oikonomou added.

The amount of sleep someone needs depends on several factors, especially one's age. In the U.S., most guidelines recommend that adults sleep between seven and nine hours each night. Yet, one out of every three American adults do not get enough sleep, according to the Centers for Disease Control and Prevention. Poor sleep has also been linked to a higher risk of obesity, diabetes, high blood pressure, heart disease, poor mental health and even dying early.

This study is limited in that it relies on self-reported sleep patterns and is cross sectional in nature, so the relationship between sleep patterns and atherosclerotic activity is based on a single point in time. Further research is needed, especially to look at whether too much sleep is harmful, which hasn't been studied as well as getting too little.

To reap heart benefits of a plant-based diet, avoid junk food

Plant-based diets are becoming more popular in many areas of the world, but the health benefits of this dietary pattern may depend largely on the specific foods consumed. A new study being presented at the American College of Cardiology's Annual Scientific Session Together with World Congress of Cardiology (ACC.20/WCC) suggests that people following a plant-based diet who frequently consumed less-healthful foods like sweets, refined grains and juice showed no heart health benefit compared with those who did not eat a plant-based diet.

"Based on these results, it seems that simply following a plant-based or vegetarian diet is not enough to reduce cardiovascular disease risk," said Demosthenes Panagiotakos, PhD, professor of biostatistics, research methods and epidemiology at Harokopio University of Athens, Greece and the study's lead author. "It is also important to focus on specific, healthful plant-based food groups to see a benefit in terms of reducing cardiovascular disease."

Researchers tracked eating behavior and the development of heart disease among more than 2,000 Greek adults over a 10-year period, beginning in 2002. Participants were asked to complete a detailed food frequency survey at the time of enrollment, after five years and after 10 years.

At the end of the study period, researchers analyzed the relationship between diet and the development of cardiovascular disease using a dietary index that divided participants into three groups based on the number of animal-based foods (which included meats as well as animal-derived products such as eggs and dairy) they consumed per day. Overall, men eating fewer animal-based foods were 25% less likely to develop heart disease compared to men eating more animal-based foods. The same overall trend was seen in women, but the relationship was less strong, with an overall risk reduction of about 11% among women eating the fewest animal-based foods.

Even though the difference in cardiovascular disease risk was significant between these groups, the overall difference in consumption of animal-based foods was relatively small. Those following a more plant-based diet consumed, on average, three animal-based foods daily while those following a less plant-based diet consumed five.

"These findings highlight that even a small reduction in the daily consumption of animal-based products--principally the less healthy foods, such as processed meat products--accompanied by an increase in healthy plant-based foods may contribute to better cardiovascular health," Panagiotakos said.

Focusing in on participants who followed a more plant-based diet, researchers then categorized each participant's diet as either healthful (reflecting increased consumption of fruits, vegetables, whole grains, nuts, legumes, oils and tea or coffee) or unhealthful (reflecting increased consumption of juices,

sweetened beverages, refined grains, potatoes and sweets). Only participants following a healthful plant-based diet had a significant reduction in cardiovascular risk compared to those who ate more animal-based products.

Differences in eating patterns--and associated cardiovascular risk reduction--were also observed between women and men. In general, men ate about three times per day while women tended to snack more, eating four to five times daily. At the same time, women showed a more dramatic increase in heart disease risk when eating an unhealthful plant-based diet and a more dramatic reduction in risk when eating a healthful plant-based diet compared to men who fell into the same two categories. This suggests that snacking on healthful foods can be beneficial while snacking on unhealthful foods can bring higher risks, Panagiotakos said.

The study was limited by its reliance on questionnaires to track participants' diets. However, the findings bolster evidence for the heart health benefits of a plant-based diet and could help inform future dietary guidance for prevention of cardiovascular disease.

"In the future, I believe it will be useful if cardiovascular disease prevention guidelines offer clearer and specific nutrition suggestions, in terms of the types of foods that are recommended and the portions that should be consumed," Panagiotakos said.

High blood pressure surprisingly common in female college athletes

While many college athletes may seem like they are in peak physical condition, they can still face significant cardiovascular risks. Nearly half of a cohort of female athletes at two U.S. universities were found to have higher than normal blood pressure levels, according to research presented at the American College of Cardiology's Annual Scientific Session Together with World Congress of Cardiology (ACC.20/WCC).

"There have been very few studies describing the female athlete's heart and risk factors that might lead to cardiac morbidity and mortality in this group," said Cecil Rambarat, MD, cardiology fellow at the University of Florida and the study's lead author. "This work gives us a baseline through which we can study the female collegiate athlete's heart in comparison to the male athlete's heart."

The study drew data from 329 female athletes participating in collegiate sports at the University of Florida or University of Georgia. Each participant's blood pressure was measured as part of a pre-participation medical examination. Researchers classified participants' blood pressure according to the 2017 ACC/AHA High Blood Pressure in Adults guideline, defining normal blood pressure as less than 120 mm Hg systolic and less than 80 mm Hg diastolic; elevated blood pressure as 120-129 mm Hg systolic and less than 80 mm Hg diastolic; hypertension stage 1 as 130-139 mm Hg systolic or 80-89 mm Hg diastolic; and hypertension stage 2 as 140 or more mm Hg systolic or 90 or more mm Hg diastolic.

Analysis revealed that 47% of the athletes had blood pressure exceeding normal levels, a proportion far higher than the 5-10% that would be expected in a general population of college-age women, Rambarat said. Of these women with abnormal blood pressure values, 61% had values classified as elevated blood pressure, 38% had values in the stage 1 hypertension category and 1% had values in the stage 2 hypertension category.

"That's really a remarkable proportion given that these are young, supposedly healthy women," Rambarat said. "It's something that requires further study. If these female athletes are developing high blood pressure at a younger age--maybe associated with their training, maybe associated with other lifestyle measures--we may need to start thinking about better ways of modifying any identifiable risk factors, or potentially [consider] starting [some] patients on medication for high blood pressure at a younger age."

The researchers also found significant differences in blood pressure levels among athletes involved in different sports and between sports with varying degrees of dynamic components (time spent actively moving) and static components (bursts of intense exertion against a static object or force). For example, women who played softball--a sport with a low static component and moderate dynamic component--were found to have a high prevalence of elevated blood pressure, while those involved in gymnastics--which has a high static component and low dynamic component--had normal blood pressure.

Researchers said the study is especially important because female athletes have not traditionally been studied as closely as their male counterparts. Decades of research on male athletes has revealed that many have a larger than normal heart and lower than normal resting heart rate, among other differences, in a pattern commonly referred to as "athlete's heart." Rambarat said the new study suggests female athletes may also have unique cardiovascular characteristics that warrant further study. For example, future studies could incorporate images of the heart, such as echocardiograms, with other measures to understand whether female athletes show an overall pattern of changes similar to what has been found in males.

The study was limited by its relatively small sample size and the fact that blood pressure measurements were taken only at a single point in time. According to the 2017 ACC/AHA guideline, blood pressure measurements should be taken on at least two occasions to confirm a diagnosis of high blood pressure. Over time, high blood pressure causes damage to arteries and restricts blood flow, which can weaken the heart muscle or lead to events such as a heart attack or stroke.