Strenuous activity predicts greater longevity

Shift some of your easy walking to fast walking

Physical fitness experts tout the benefits of moderate-intensity activity. Perhaps emphasizing "moderate" makes exercise seem more accessible to more people. But a study from Australia showed that strenuous physical activity conferred greater health benefits than less strenuous activity. Researchers used data from 204,542 participants in the Sax Institute’s 45 and Up study. The randomly selected subjects, between ages 45 and 75 at baseline, lived in New South Wales. Compared to those who reported no moderate or vigorous physical activity (MVPA), those who reported getting 150-300 minutes of MVPA per week had a 54 percent lower risk of dying during the average 6.5-year follow-up period. For participants who reported getting some MVPA, those who reported getting at least 30 percent of their overall MVPA as strenuous had an additional 13 percent lower risk of dying, compared to those who did not report any strenuous physical activity.

Thus, middle-aged and older Australians who got lots of physical activity (in this case, twice the widely recommended minimum level) had less than half the risk of dying compared to their completely sedentary counterparts. Plus, participants whose overall physical activity included a substantial fraction of strenuous activity got an additional longevity bonus. If you are completely sedentary, good luck in living to a ripe old age. If not, you’ll be well served by moving more and moving more strenuously.

A sedentary lifestyle leads to high levels of post-meal blood fats, which predict greater risk of cardiovascular disease. Research suggests that post-meal exercise reduces insulin spikes. Might micro-periods of intense exercise that interrupt long episodes of sitting lower post-meal blood fats? Researchers recruited four men and four women for an experiment. Participants either 1) sat for 8 hours with exercise interruptions every 12 minutes (160 seconds of exercise over the 8-hour period), or 2) sat for 8 hours without exercise. The interruptions consisted of 4 seconds of maximal effort on a stationary bicycle followed by a 45-second rest period.

Compared to sitting, micro-bouts of exercise did not affect blood insulin or glucose, but did reduce blood triglycerides by 31 percent and increased body fat oxidation by 43 percent the following day. Thus, tiny increments of highly strenuous exercise lowered blood fats and burned fat. Is your excuse to avoid exercising is a lack of time? If so, couldn’t you could find time in your busy daily schedule for 3 minutes of heavy exercise?

I now include 5 minutes of high-intensity interval training in each of my thrice weekly sessions. Such short sessions predict cardiovascular benefits. For those of you who take after-meal walks, how about turning one of those daily walks into a strenuous, fast walk? It won’t require any more time but could make you healthier.