A new study says you need 10 hours of exercise a week. Can that really be possible?

Accelerometer data from 17,000 UK Biobank participants were used to estimate how weekly physical activity relates to stroke or heart-attack risk. A 30% risk reduction corresponded to roughly 560 to 610 minutes of moderate-to-vigorous activity per week. Less-fit individuals required up to about 50 additional minutes to achieve similar benefits. WHO guidance of 150 minutes per week was associated with an 8 to 9% risk reduction, which was described as meaningful. Experts cautioned that the findings should be interpreted carefully and did not imply WHO recommendations are wrong. The results also did not rule out large cardiovascular benefits from short, high-intensity exercise such as interval training.

"The study analyzes accelerometer data collected over the course of a week from 17,000 individuals included in the U.K. Biobank, a long-term health study. It finds that for the average person to experience a 30 percent reduction in the risk of stroke or heart attack, they need to be doing around 560 to 610 minutes of moderate to vigorous physical activity a week. And people who are less fit may need to do as much as 50 minutes more exercise than people who are more fit to see the same benefits, according to the study."

"For comparison, the WHO guidelines of 150 minutes of moderate exercise a week is associated with an 8 to 9 percent reduction in risk. That's not nothing, Heffron says. If we came up with a new medicine that improved risk that much, we'd be thrilled, he says. The results don't indicate that the WHO's guidance on exercise is wrong, Heffron says."

"The study's authors are playing down the benefit of physical activity, says Sean Heffron, an assistant professor of medicine and a cardiologist specializing in exercise science at New York University. Some cardiovascular and fitness experts say the new research needs to be approached with a healthy dose of caution. The results don't indicate that the WHO's guidance on exercise is wrong, Heffron says. Nor do they suggest that short, high-intensity bursts of exercise such as high-intensity interval training aren't also associated with large reductions in cardiovascular disease risk, says Ulrik Wislff, a professor at the"

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