For years, U.S. health agencies have recommended a minimum of 150 minutes of exercise per week —but a new study involving data from more than 30 million people found that just 11 minutes of moderate-to-vigorous aerobic exercise per day could lower the risk of premature death by almost 25%.

Study details and key findings

For the study, which was published Tuesday in the British Journal of Sports Medicine, researchers reviewed 196 articles that included data from more than 30 million people. On average, participants were tracked for 10 years. In their analysis, the researchers looked for associations between people's activity levels and their health and longevity.

Aerobic exercise includes activities like walking, dancing, running, jogging, cycling, and swimming. Overall, 75 minutes of moderate-to-vigorous aerobic exercise each week was associated with a 23% decline in the risk of premature death. In addition, this amount of exercise lowered the risk of cardiovascular disease by 17% and the risk of cancer by 7%.

Researchers identified greater benefits for certain types of cancer. For example, individuals who exercised for 75 minutes exercise each week, or 11 minutes a day, experienced a 14% to 26% lower risk of head and neck, myeloid leukemia, myeloma, and gastric cardia cancers.

Among individuals with lung, liver, endometrial, colon, and breast cancer, researchers reported a 3% to 11% percent lower risk. 

According to the researchers, this analysis represents the largest ever study that evaluates the association between physical activity levels and heart disease, cancer, and early death risk. The study's findings show that even a small amount of aerobic exercise can improve longevity and lower risks of developing or dying of certain diseases.

Commentary

With the exception of work-related activities, 2 out of 3 individuals reported activity levels lower than the recommended 150 minutes per week. Meanwhile, fewer than 1 in 10 exercised more than 300 minutes each week. 

"One in 10 premature deaths could have been prevented if everyone achieved even half the recommended level of physical activity," the authors wrote in the study. In addition, "10.9% and 5.2% of all incident cases of CVD (cardiovascular disease) and cancer would have been prevented."

"If you are someone who finds the idea of 150 minutes of moderate-intensity physical activity a week a bit daunting, then our findings should be good news," said study author Soren Brage of the Medical Research Council Epidemiology Unit at the University of Cambridge. 

"Doing some physical activity is better than doing none. This is also a good starting position — if you find that 75 minutes a week is manageable, then you could try stepping it up gradually to the full recommended amount," Brage added.

"Moderate activity doesn't have to involve what we normally think of exercise, such as sports or running. Sometimes, replacing some habits is all that is needed," added author Leandro Garcia from Queen's University Belfast. 

"This is a compelling systematic review of existing research," said CNN Medical Analyst Leana Wen, an emergency physician and public health professor at George Washington University, who was not involved in the study. "We already knew that there was a strong correlation between increased physical activity and reduced risk for cardiovascular disease, cancer and premature death. This research confirms it, and furthermore states that a smaller amount than the 150 minutes of recommended exercise a week can help."

While the authors did not have details on the specific types of physical activity included in the study, some experts do have theories on how physical activity could decrease risk for chronic diseases and premature death.

"There are many potential mechanisms including the improvement and maintenance of body composition, insulin resistance and physical function because of a wide variety of favorable influences of aerobic activity," said Haruki Momma, an associate professor of medicine and science in sports and exercise at Tohoku University, who was not involved in the study.

Regular exercise could also benefit immune function, lung and heart health, inflammation levels, hypertension, cholesterol, and amount of body fat, according to Eleanor Watts, a postdoctoral fellow in the division of cancer epidemiology and genetics at the National Cancer Institute.

"These translate into lower risk of getting chronic diseases," said Peter Katzmarzyk, associate executive director for population and public health sciences at Pennington Biomedical Research Center. (Melillo, "Changing America," The Hill, 3/1; Rogers, CNN, 3/1; Reynolds, Washington Post, 2/28)