More the exercise, the better it is for your heart health: Oxford study

By Rahul Vaimal, Associate Editor
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It has long been understood that being physically active is good for you, particularly when it comes to preventing things like heart attacks and strokes.

A new large study led by the University of Oxford suggests that physical exercise may be even more important for the prevention of cardiovascular disease than previously known and the more activity the better.

The Study

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To measure physical activity, researchers in the United Kingdom got 90,211 individuals to wear an accelerometer (a small, lightweight motion sensor) on their wrist over a seven-day period between 2013 and 2015. The researchers tracked the participants’ health for an average of five years.

Overall, there were 3,617 cases of cardiovascular disease diagnosed in the participants, who were part of the wider UK Biobank study of people between 40 and 69 years old. Cases of cardiovascular disease decreased among the participants as the amount of moderate and vigorous physical activity increased. What’s more, there was no threshold where the effects of exercise stopped improving cardiovascular health, the study found. Those who were most active, in the top 25 percent, had an average reduction in risk of between 48 percent and 57 percent.

Pandemic and reduced activity

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“During the pandemic, because of lockdowns or self-imposed isolation, people have not been getting as much ‘incidental’ activity, particularly in relation to travel or movement around an office, for example,” said Terence Dwyer, a professor emeritus of epidemiology at the University of Oxford and an author of the study.

“This means that they need to take more purposeful activity to maintain even what they were doing previously. Our findings should give them more confidence that this is something they really should pay attention to. It also should provide confidence in increasing their PA (physically activity) beyond levels they might have regularly taken prior to the pandemic.”

People in the top 25 percent did about 50 minutes per week of vigorous-intensity physical activity such as running, while those in the bottom 25 percent had less than 10 minutes per week of vigorous-intensity physical activity, said lead study author Aiden Doherty, an associate professor at University of Oxford’s Nuffield department of population health.

Although those who exercised more were also more likely to not smoke, drink less alcohol and have a healthy body weight, the researchers said they accounted for these factors in their analysis and found that the association between increased exercise and a decrease in cardiovascular disease was still strong.

These results, the researchers said, demonstrated that exercise alone has a significant effect on the risk of being diagnosed with cardiovascular disease. Cardiovascular disease is the leading cause of death globally, claiming around 17.9 million lives each year, the researchers said.

An accurate way of understanding the impact

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Most studies examining the benefits of physical activity typically use questionnaires, which can be less accurate, given that most people are unable to accurately recall all activity that takes place throughout the day, both for leisure and as part of a person’s daily routine.

The researchers said they were confident that wearing the device, which they described as a “research-grade Fitbit,” was an accurate way to reflect an individual’s habitual activity over time even though it only recorded seven days’ worth of physical activity.

Other research had shown that activity measured in this way was “moderately stable,” Mr. Doherty said, and more research was being conducted to gauge its accuracy.

“Using this more accurate form of measurement, and in a large number of people, we found the lowest risk for cardiovascular disease in the UK Biobank cohort is seen at the highest level of physical activity, whether total, moderate or vigorous intensity,” he said.

“This is the largest ever study of device-measured physical activity and cardiovascular disease. It shows that physical activity is probably even more important for the prevention of cardiovascular disease than we previously thought. Our findings lend further weight to the new World Health Organization (WHO) guidelines on physical activity which recommend at least 150 to 300 minutes of moderate to vigorous aerobic activity per week for all adults.”

The WHO revised its guidelines on physical exercise in December 2020. The UN agency now recommends that adults get at least 150 minutes, that’s 2.5 hours, of moderate to vigorous physical activity weekly.

The results of the study were similar for men and women, although the benefits of vigorous exercise appeared to be particularly strong for women.