A large observational study of UK adults has found that meeting the standard exercise guideline of 150 minutes of moderate-to-vigorous activity a week lowers cardiovascular risk by only about 8 to 9 percent — far less protection than many assume — and that substantially larger benefits require roughly four times as much exercise. The findings, published in the British Journal of Sports Medicine, were drawn from researchers at Macao Polytechnic University and reported this month by the BMJ Group.
The study followed 17,088 UK Biobank participants, average age 57, who wore wrist accelerometers for a week to measure daily activity and completed a stationary-cycling test to estimate cardiorespiratory fitness. Over an average of 7.8 years of follow-up, researchers recorded 1,233 cardiovascular events, including 874 cases of atrial fibrillation, 156 heart attacks, 111 cases of heart failure and 92 strokes. Substantial protection — defined as more than a 30 percent reduction in cardiovascular risk — was associated with 560 to 610 minutes of moderate-to-vigorous exercise a week, a threshold only 12 percent of participants reached. People with lower baseline fitness needed 30 to 50 more weekly minutes than fitter participants to achieve the same risk reduction.
"This finding highlights the steeper challenge faced by deconditioned populations," the study authors wrote, adding that future guidance might need to separate a minimal activity level needed for basic safety from the larger volume required for optimal risk reduction.
Cardiologists urge caution on the numbers
Outside experts who were not involved in the study cautioned against reading it as a call to nearly quadruple exercise targets. Keith Diaz, a researcher at Columbia University Medical Center and a volunteer with the American Heart Association, which currently recommends at least 150 minutes of moderate activity weekly, said in comments reported by Healthline that "I would urge caution in interpreting the specific recommendation that people may need three to four times the current physical activity guidelines," noting that only about half of U.S. adults currently meet the existing benchmark.
150 minutes is a solid baseline. But it's just that: a baseline.
Kevin Shah, MD, MemorialCare Heart & Vascular Institute
Michael Fredericson of Stanford University argued the more useful takeaway is that small increases in activity produce the largest relative benefit for the least active people, rather than that everyone needs to reach 600 minutes, which he called "far beyond what is necessary for substantial health benefits and not feasible for most."
Because the study is observational, it cannot prove that exercise directly caused the lower cardiovascular risk, only that the two were strongly associated, and the authors noted their Biobank sample may have been healthier than the general population. Researchers said the next step is testing whether personalized activity targets, calibrated to a person's starting fitness level rather than a single fixed number, could improve on blanket guidelines.
