Thursday, June 11, 2015
Exercise and you could live longer
In a study called Leisure Time Physical Activity and Mortality: A Detailed Pooled Analysis of the Dose-Response Relationship, found that by meeting the 2008 Physical Activity Guidelines for Americans minimum by either moderate- or vigorous-intensity activities was associated with nearly the maximum longevity benefit.
The study authors observed a benefit threshold at approximately 3 to 5 times the recommended leisure time physical activity minimum and no excess risk at 10 or more times the minimum. In regard to mortality, health care professionals should encourage inactive adults to perform leisure time physical activity and do not need to discourage adults who already participate in high-activity levels
Researchers pooled data from 6 studies in the National Cancer Institute Cohort Consortium (baseline 1992-2003). Population-based prospective cohorts in the United States and Europe with self-reported physical activity were analyzed in 2014.
A total of 661,137 men and women (median age, 62 years; range, 21-98 years) and 116 686 deaths were included. Median follow-up time was 14.2 years
Using this data, the researchers stratified the adults by their weekly exercise time, from those who did not exercise at all to those who worked out for 10 times the current recommendations or more (meaning that they exercised moderately for 25 hours per week or more).
They found that, unsurprisingly, the people who did not exercise at all were at the highest risk of early death.
But those who exercised a little, not meeting the recommendations but doing something, lowered their risk of premature death by 20 percent.
Those who met the guidelines precisely, completing 150 minutes per week of moderate exercise, enjoyed greater longevity benefits and 31 percent less risk of dying during the 14-year period compared with those who never exercised.
The sweet spot for exercise benefits, however, came among those who tripled the recommended level of exercise, working out moderately, mostly by walking, for 450 minutes per week, or a little more than an hour per day. Those people were 39 percent less likely to die prematurely than people who never exercised.
At that point, the benefits plateaued, the researchers found, but they never significantly declined. Those few individuals engaging in 10 times or more the recommended exercise dose gained about the same reduction in mortality risk as people who simply met the guidelines. They did not gain significantly more health bang for all of those additional hours spent sweating. But they also did not increase their risk of dying young.
The other new study Effect of Moderate to Vigorous Physical Activity on All-Cause Mortality in Middle-aged and Older Australians. reached a somewhat similar conclusion about intensity. While a few recent studies have intimated that frequent, strenuous exercise might contribute to early mortality, the new study found the reverse.
For this study, Australian researchers closely examined health survey data for more than 200,000 Australian adults, determining how much time each person spent exercising and how much of that exercise qualified as vigorous, such as running instead of walking, or playing competitive singles tennis versus a sociable doubles game.
The researchers concluded that among people reporting any activity, there was an inverse dose-response relationship between proportion of vigorous activity and mortality. The findings suggest that vigorous activities should be endorsed in clinical and public health activity guidelines to maximize the population benefits of physical activity.
They found that meeting the exercise guidelines substantially reduced the risk of early death, even if someone’s exercise was moderate, such as walking.
However if someone engaged in even occasional vigorous exercise, he or she gained a small but not unimportant additional reduction in mortality. Those who spent up to 30 percent of their weekly exercise time in vigorous activities were 9 percent less likely to die prematurely than people who exercised for the same amount of time but always moderately. Those people who spent more than 30 percent of their exercise time in strenuous activities gained an extra 13 percent reduction in early mortality, compared with people who never broke much of a sweat. The researchers did not note any increase in mortality, even among those few people completing the largest amounts of intense exercise.
The bottom line is that anyone who is physically capable (always check with your doctor before starting) of activity should try to reach at least 150 minutes of physical activity per week. Of those minutes around 20 to 30 minutes of that should be vigorous activity.