A study published in the British Journal of Sports Medicine found that even 10 minutes per week of light to moderate physical activity was associated with significantly lower risks of death. They also found that there is an increasing benefit, with more activity resulting in even lower risks of death, up to 1,500 minutes or more per week.
The researchers looked at self-reported lifestyle and behavioral data from the CDC's National Health Interview Survey between 1997 and 2009, and then matched responses with diagnosis and death data from the National Death Index. They excluded participants with serious chronic diseases, incomplete responses, or less than three years of follow-up, and ended up with data from 88,140 US adults ages 40 to 85, followed for about nine years.
Participants had reported a wide range of activities which fit into light, moderate, or vigorous categories, and the researchers analyzed all of this in different ways. First, because they were mostly interested in light to moderate activity, they "translated" every minute of reported vigorous activity into two minutes of moderate activity, per accepted research protocols. Then, they divided everyone into eight groups based on reported minutes of light to moderate activity per week, ranging from completely inactive (zero minutes), to a little (between 10 and 59 minutes), and on up to over 1,500 minutes per week.
What was fascinating (and also depressing) was that the largest group by far was the completely inactive group (36,702 people, 42% of the total). As a matter of fact, over half didn't meet the minimum recommended amount of 150 minutes of weekly activity (52,136 people, 59%), which fits with prior research. I suppose it's heartening that a fair amount did get their 150+ minutes weekly (36,004 people, 41%).
Researchers wanted to know how little activity provided benefit
Even after adjusting for smoking, alcohol intake, and body mass index, as little as 10 minutes per week of light to moderate activity was associated with an 18% lower risk of death from any cause. The benefits of more and more exercise followed a fairly obvious dose-response curve, up to 1,500 minutes per week, which had a 46% lower risk of death from any cause (meaning the higher the "dose" of activity, the lower the risk of death). They then looked at cardiovascular (heart attack, stroke) and cancer death risk, and found very similar results.
Then they went back and looked at light to moderate vs. vigorous activity, and found that comparing them by minutes per week, there was a much greater benefit to vigorous physical activity, i.e., more bang for the buck. Those who reported 10 to 59 minutes per week of vigorous activity had a 26% lower risk of death from all causes, as compared to the light/moderate group at 19%. Again, the minutes per week of vigorous activity was associated with a clear dose-response curve, with more being better on up to 600 or more minutes per week and a 42% lower risk of death (that's as high as they went, because only 1,973 participants reported that much). Again, when they looked at cardiovascular and cancer deaths, they had much the same result.
Why is it that all activity seems to extend our life?
We know that exercise has multiple positive physical effects on weight loss and maintenance, blood sugar control, inflammation, cardiovascular and immune function, and more. Exercise has so many benefits, it's better than any medication. It can't be packed into a pill.
These findings underscore (again) that when it comes to exercise, every little bit counts, and a lot counts even more. The recommended minimum for heart health benefits (150 minutes of moderate intensity activity per week — like brisk walking) can be an admirable goal for some people, or a bare minimum for others, and everyone will still reap benefits.
You do not have to go to the gym
This study included a wide variety of activities. We can discover an activity that we enjoy, and do it regularly. We can also work activity into our regular day. I saw a sign hanging on a door recently, a brightly colored advertisement: "Free Exercise Equipment Inside! Open This Door for Your Free Workout Machine!" The door led to the stairwell.
And that's the idea. Every little bit counts, so if you are blessed with the ability and the good health to move your body, do it! Park farther away from the entrance of stores and walk extra. Grab a basket, not a cart, and work your biceps while you shop. While waiting for the train, the bus, or to board a plane, see how many steps you can log. If you're talking on the phone, pace, or at least stand and do some leg moves. Like to watch TV? Get a used exercise bike and set it in your living room. Or grab an exercise mat and do some core work while watching your favorite TV show.