KATHMANDU — Physical activity, moderate to vigorous in any form, could reduce the risk of premature death in older women from any cause by 70 percent, a US based study suggests.
The study involved more than 17,700 women with an average age of 72 who were asked to wear accelerometers every day for a week. Researchers followed the participants for more than two years on average.
During this time, 207 women died. Lack of exercise or physical activity is estimated to cause as many deaths each year as smoking.
Current guidelines recommend at least 150 minutes a week of moderate intensity physical activity, or 75 minutes a week of vigorous-intensity aerobic physical activity (or a combination of the two), and muscle-strengthening exercises two or more days a week.
For the study published in Circulation, researchers sorted women into four groups from most to least active and they found those who got the most moderate to vigorous physical activity, such as brisk walking, were up to 70% less likely to die during the study period. Getting more low-intensity activity, however, didn’t appear to influence the odds of death.
“This study supports current guidelines for physical activity, such as those from the federal government and the American Heart Association, that emphasize moderate-intensity physical activity. It also adds to existing evidence that can inform upcoming physical activity guidelines over time,” I-Min Lee, MBBS, ScD, associate epidemiologist at Brigham and Women’s Hospital, and first author of the study.
Earlier studies based on participants’ own assessments of their activity levels have found regular exercise associated with up to about a 30% reduction in mortality rates, Lee and colleagues note online November 6 in Circulation.
“The fact that physical activity lowers the risk of premature mortality is not a new fact — we have many studies showing this,” Lee said adding, “Previous studies have primarily relied on self-reported physical activity, and self-reports tend to be imprecise.”
This is one of the first studies to investigate physical activity, and a clinical outcome, using the newer generation triaxial wearable devices which have increased sensitivity to recognize physical activity and are capable of more precise measurements than the previously used uniaxial devices, or studies relying on self-reports only.
“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,” stated I-Min Lee.
Light physical activity, such as slow walking, was not associated with lower death rate during the study.
The accelerometers used in the current study could measure activity along three planes: up and down, front to back and side-to-side. This can help researchers see not just if people are moving, but the intensity of their movements.
Half of the participants spent at least 28 minutes in moderate to vigorous physical activity on an average day, or around 196 minutes a week.
Doctors typically advise people to get at least 150 minutes a week of moderate to vigorous exercise.
Even though some previous research has linked excessive sedentary time to a higher risk of premature death, the current study didn’t find an association between these two things.
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