Previous studies, which relied on self-reported data, have found that active people have a 20 to 30 percent lower risk of death from all causes. But research published Monday in the journal Circulation found older women most benefit from moderate to vigorous physical activities, which were associated with a 60 to 70 percent lower risk of death.
Light physical activity and sedentary behavior, on the other hand, were not associated with death rate in this study – though the researchers point out low-intensity workouts may offer health benefits they didn’t study.
The findings are based on research conducted between 2011 and 2015 on nearly 17,000 older women – average age 72 – whose physical activity was measured using a wearable device that can track movements along three planes: front to back, side to side and up and down.
“We used devices to better measure not only higher intensity physical activities, but also lower intensity activities and sedentary behavior, which has become of great interest in the last few years,” said first author I-Min Lee, a professor of medicine and epidemiology at Harvard University.
The women were asked to wear the devices for at least 10 hours a day on at least four days over a week-long period. After a follow-up with the participants – which occurred about two and a half years later, on average – the team found 207 women had died.
The participants, all fairly healthy and mostly white, were selected from the Women’s Health Study. The findings may have limited applicability to other populations, according to the team. The researchers chose to study older women because they were particularly interested in how light intensity activities can improve a person’s health outlook.
“Younger people in their 20s and 30s generally can participate in vigorous intensity activities, such as running or playing basketball,” Lee said. “But for older people, vigorous intensity activity may be impossible, and moderate intensity activity may not even be achievable.
“So, we were interested in studying potential health benefits associated with light intensity activities that most older people can do.”
The team noted that while light activity was not associated with a reduced death risk, such actions could be associated with other health benefits.
The findings support 2008 federal guidelines, which recommend at least 150 minutes a week of moderate intensity movements or 75 minutes a week of vigorous-intensity aerobic physical activity – or a combination of the two. Muscle-strengthening exercises should also be performed two or more days a week.
“We hope to continue this study in the future to examine other health outcomes, and particularly to investigate the details of how much and what kinds of activity are healthful,” Lee said. “What is irrefutable is the fact that physical activity is good for your health.”