Even Small Differences in Exercise in Older People Are Associated with Greater Remaining Life Expectancy

One of the interesting results that has emerged from the growing use of accelerometers in studies of exercise is that even small differences in activity levels have an noticeable correlation with mortality rates and life expectancy:

Even for people who already exercised, swapping out just a few minutes of sedentary time with some sort of movement was associated with reduced mortality. Researchers looked at data from approximately 3,000 people aged 50 to 79 who participated in the National Health and Nutrition Examination Survey (NHANES). For the study, subjects wore ultra-sensitive activity trackers, called accelerometers, for seven days. For these same people, the agency then tracked mortality for the next eight years. The results were striking. The least active people were five times more likely to die during that period than the most active people and three times more likely than those in the middle range for activity. "When we compare people who exercise the same amount, those who sit less and move around more tend to live longer. The folks who were walking around, washing the dishes, sweeping the floor tended to live longer than the people who were sitting at a desk."

Previous activity-tracking studies have drawn similar conclusions. But such studies usually ask participants to monitor their own exercise frequency and quantity, numbers they notoriously over-report. Also, the trackers used for NHANES have a higher level of precision than what's typically employed. "Because the device captures the intensity of activity so frequently, every minute, we can actually make a distinction between people who spent two hours a day doing those activities versus people who spent an hour and a half." To account for chronic conditions or illness influencing mortality rates, researchers statistically controlled for factors like diagnosed medical conditions, smoking, age and gender. They also completed a secondary examination from which they entirely excluded participants with chronic conditions. Though the scientists didn't discover any magic threshold for the amount a person needs to move to improve mortality, they did learn that even adding just 10 minutes per day of light activity could make a difference. Replacing 30 minutes of sedentary time with light or moderate-to-vigorous physical activity produced even better results.

Link: https://news.upenn.edu/news/new-penn-study-links-moving-more-decreased-mortality


Maybe exercise makes people live longer, but I find it at least as plausible that people of better health simply exercise more. Worse health usually means a higher degree of fatigue which naturally translates into less exercise of any kind. Controlling for "chronic conditions" and the like doesn't help much. I mean, did they distinguish between the 65 year old with the 75 year old body (without no obvious conditions) and the 65 year old with the 55 year old body? The second is likely to both exercise more and live longer because he's biologically younger.

Of course, they're not mutually exclusive, could be both that healthier people exercise more and that exercise makes people healthier, just saying I'm not onboard with the "yay exercise" conclusion (based on this study or any study like this one). Maybe if they made a similar study where they choose randomly who should exercise and not...

Posted by: Northus at March 2nd, 2016 4:00 PM

Northus pointed towards the shortcomings of this study and I fully agree. A person with higher biological age may be less able to exercise and may be more likely to die.

The question is if you force the people who exercise little, to exercise more, does this increase their life expectancy significantly?

Posted by: Waverunner at March 3rd, 2016 2:56 AM

I'm a few years past 65 and my experience has been that a simple exercise program of (2) 35 minute sessions a week makes all the difference in terms of being able to get around when you want to....from almost needing a cane to walk and being unsure on one's feet...to being able to get up and move without thinking too much about it...though watching for twisted knees and so forth is important.

I watch my diet...take many supplements...but am aware that exercise is a 3rd leg on the stool and might be almost the most important one. I don't need corroboration from a controlled study to understand this...I've done my own A-B study.

Argue all you want...but do it out on a walk?

Posted by: R at March 9th, 2016 5:53 AM

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