Exercise is one of the best things you can do to boost your odds of a long and healthy life. But research out this week might be setting the bar a bit too high, at least for the average weekend warrior.
Scientists at Macao Polytechnic University in China and others examined data from a study of middle-aged residents in the UK. They found evidence that it took a sizeable amount of moderate-to-vigorous physical activity—roughly 10 hours a week—to greatly lower people’s risk of heart attacks and other cardiovascular disease. Though lighter exercise can still promote good heart health, the researchers argue that experts should be honest with people about these potentially higher benchmarks.
“Current [exercise] guidelines provide a universal but modest safety margin, whereas optimal cardiovascular protection may require substantially higher activity volumes,” the authors wrote in their paper, published this week in the British Journal of Sports Medicine.
A high threshold
Studies have shown that any amount of exercise is better than none. That said, health organizations have generally recommended that people shoot for at least 150 minutes of moderate-to-vigorous physical activity a week—an amount consistently linked to various health improvements.
While this recommendation sets a good baseline, the study authors say that not enough research has looked at how people can individually respond to exercise. In other words, the same weekly “dose” of exercise might not confer the same level of protection against cardiovascular disease for two different people.
To get a better sense of exercise’s cardiovascular benefits, the researchers delved into the UK Biobank, a long-running project following the health of middle-aged people in the country. They focused on a subset of roughly 17,000 volunteers who wore an accelerometer on their wrist for a week, providing an objective measure of their physical activity.
Over a median length of nearly eight years, there were about 1,200 episodes of cardiovascular disease recorded during the study. And as expected, regular exercisers were less likely to have heart problems in general.
However, the researchers found the recommended level of moderate-to-vigorous physical activity, 150 minutes a week, was associated with an 8% to 9% lower risk of cardiovascular disease across different fitness levels. To get a “substantially” lower risk of at least 30%, people needed to exercise between 560 and 610 minutes a week, depending on their fitness level, the researchers calculated.
For context, that amount of exercise is about three to four times higher than the current recommendation. It’s also a greater duration than the time it would take the average runner to finish a marathon (roughly four-and-a-half hours).
If that isn’t bad enough, the researchers also found variation in how much exercise it took for these heart benefits to emerge between people of different fitness levels. Typically, people who were less fit to begin with needed to exercise more to get the same level of heart protection as more fit people.
What this means
As with any study, this one carries important caveats. Namely, it’s an observational study, meaning it can only show a correlation between the amount of exercise someone does and their lower likelihood of cardiovascular disease, not a cause-and-effect relationship.
Even if the study’s findings are valid, though, there’s room to disagree with the authors’ interpretation of their conclusion, in my opinion.
My main quibble is with the researchers’ definition of “substantial.” Why does that have to mean a 30% lower risk? Why not 20%? That level of reduction, according to the study, would take about 340 to 370 minutes of exercise a week—still double the current recommendation but certainly more achievable than four times the amount.
As the researchers admit, 150 minutes of exercise a week is still healthy. And assuming these findings hold up, I don’t think reducing your chances of a heart attack or stroke by 8% to 9% is anything to sneeze at.
Of course, it is still important to try quantifying the exact benefits of exercise. And perhaps this research will motivate some people to push themselves a little more at the gym. Personally speaking, though, as a former marathon runner turned jogger, I’m not feeling too stressed about meeting that high bar. According to the study, only 12% of people in the UK Biobank actually did.