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Heart Health, Explained

Exercise Limits and Cardiovascular Disease Risk

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A study published January 12, 2021 in PLOS Medicine found that there are no limits to the amount of exercise when it comes to producing heart health benefits and that the highest levels of exercise produced the lowest risks for cardiovascular disease.

Exercise Limits and Cardiovascular Disease Risk Q&A

What’s the most important thing people should know about this study as it relates to their health?
One of the under-recognized consequences of the COVID-19 pandemic has been a decrease in exercise and other healthy lifestyle behaviors. Cardiovascular disease is the leading cause of death in the United States for both women and men, and “sitting is the new smoking” has become a catch phrase in the medical community. This new research shows that there is a direct relationship between increased activity /exercise and improved cardiovascular health. In short: more physical activity = improved health. And this benefit was observed at the highest level of exercise, including total exercise, and regardless of whether the exercise was of moderate or vigorous intensity.

The U.S. government increased exercise recommendations in 2018. Previously, federal officials recommended that adults get 150 minutes each week of exercise at moderate intensity or 75 minutes of vigorous exercise. The recommendation has been increased to 150-300 minutes of moderate intensity, or 75-150 minutes of vigorous intensity per week. This study supports the new recommendation.
What was this study seeking to determine? Has this been done before?

Much of the previous work in this area was based on self-report rather than more-reliable data obtained through measured activity. Previous research had also shown that the greatest benefit was for people who had been sedentary and then became mildly active.

Studies showed conflicting results over whether endurance sports (long distance running, cycling, etc.) had health benefits or potential harms. This study sought to obtain measured data to examine moderate, vigorous, and total activity as factors for reducing cardiovascular disease risk.

What were the results?
Moderate, vigorous, and total physical activity were each associated with lower reports of cardiovascular disease.

Any increase in activity showed benefit. The benefit was not just in those changing from a sedentary lifestyle to a low or moderate level of activity; it continued to rise with increased activity or exercise. However, the vigorous activity category did not include a significant number of endurance athletes, so the risk vs. benefit of that type of exercise was not addressed with this study.
Did the study reveal any differences concerning subgroups?
Women showed a greater benefit from vigorous physical activity than men.

When health conditions and risk factors that affect heart health risk were accounted for (including age, sex, ethnicity, education, smoking, and alcohol consumption), the benefit of physical activity persisted.
What were the strengths and shortcomings of this study’s design and execution?
This was a prospective (forward-looking) study, with a large sample size. Activity/exercise was measured rather than reported. The researchers accounted for other risk factors that impact the risk of heart disease. They also reanalyzed the data after removing the first year and then the first two years of results to account for people who were already limited by their heart disease.

There were several weaknesses. The group studied was not diverse, consisting of mostly white participants from areas not experiencing high levels of economic deprivation. In addition, activity or exercise was only tracked for seven days for each person, using a wrist-worn device called an accelerometer that detects and records movement. It is also possible that wearing the accelerometer influenced the activity level of the wearer. Finally, the study only showed an association between physical activity and improved heart health; it did not show that it was the cause.
What, if anything, should people and health care professionals do differently in the face of these findings? What are the challenges to addressing this issue?

As individuals, we need to be more aware of our activity level. Getting up to move even briefly each hour, taking short walks on breaks, and scheduling time for sports or exercise can have a significant impact. Exercise has been shown to be more effective than most medications in improving cardiovascular health.

As a society, we need to take a closer look at our built environment and think of ways to make it easier for our citizens to be more active. The current American lifestyle involves a large amount of sedentary work and leisure time. Changes, such as making shopping more walkable from neighborhoods, making paths for safely walking/cycling to work, and offering active leisure time events, can make a difference on a large scale.

Health care professionals should make activity another “vital sign.” Just like waist measurement, it is an important indicator of heart health risk. Activity level and exercise should be reviewed and discussed with patients at each visit.


Answers to your questions on timely topics in cardiac care to help make sense of research reports in the media. The series includes questions on your heart and the effect of medications, exercise, diet, and hormones.

Team Specialist

Julie Cantrell MD, OhioHealth Cardiac Rehabilitation, OhioHealth Weight Management

Q&A Editor

Teresa Caulin-Glaser, MD, FACC, FAACVPR System Vice President, Heart & Vascular Services OhioHealth Healthcare System, Columbus, Ohio

Heart Health Explained is a collaboration of Women’s Health Research at Yale and the OhioHealth Healthcare System, a nationally recognized not-for-profit organization with providers across 46 counties, offering a holistic approach to prevention, treatment and rehabilitation of heart disease. OhioHealth is staffed by physicians, psychologists, nutritionists and nurses who answer the questions of the moment on heart and vascular health.

The information provided here may help you make more informed choices. However, it is not a substitute for an individualized medical opinion or diagnosis, and everyone should always consult with their personal physicians to make decisions about their condition or treatment.