Mean and max lifespan
When a mouse cage is provided with an exercise wheel, most mice will run on it for hours every night (mice are nocturnal). Those mice tend to live longer. Do the mice have something to teach us?
There are more than a few life extension advocates who dismiss exercise as a longevity strategy because it increases mean but not maximum life span. Translation: when groups of mice that exercise are compared to similar groups of mice that are sedentary, the mice that exercise live about 10% longer on average. But the longest-lived mice in the sedentary (control) group live about as long as the longest-lived mice that exercise. This is often translated to mean that “exercise doesn’t affect the rate of aging, but helps to prevent premature death.” I would rather say that there are a few percent of mice (and people, perhaps) who will live to extraordinary old age even if they don’t exercise. Unless you know that you are one of these, exercises increases your chances of living a long time. Even if you’re sure you’re in the lucky group, you may choose to exercise because it puts you in a good mood, protects you from getting headaches and colds, and adds a dimension of interest to your life.
I’ve taught one yoga class a week since 1976, a small but very consistent part of my routine that means a lot to me. For my class, I define yoga as any physical activity that is done with concentrated awareness on the body. All exercise should be yoga. The more attention we pay to our bodies the more we learn to decode the signals about what our bodies need. This is important not just for safety, but for a general guide to self-care. It’s related to “do what feels good,” but it’s not quite the same. There are some sensations that indicate a real danger, and it is important to stop what you’re doing right now. Other sensations may be equally unpleasant, but they come from stressing the body in ways that are a fast track to strength and health. This is hormesis. Eustress. The intermittent challenge that makes us strong.
For those of us who seek a longer life, certainly it is conscious life that we value. Time we spend going through the motions of unaware, habitual activity can barely be said to be “alive”. In this sense, yoga is training for being more alive.
1. Cardio-pulmonary – exercise for the lungs, heart, and circulation
This is exercise that gets you out of breath. You have two choices: low intensity for a long time (endurance training) or high intensity for a short time (interval training). Until a few years ago, endurance was considered the way to go, simply because it seemed to make sense. But now there is evidence that high intensity exercise is not only a more efficient path to fitness, but also works better. [Ref 1; Ref 2; Ref 3; Ref 4]
(This is all based on physiological reasoning, because it is not possible to do controlled experiments with humans to see which strategy results in more life extension, and even if volunteers for such experiments could be arranged, the results would take decades to accrue.)
Some people enjoy running or hiking for hours on end, but have an aversion to the grueling output associated with interval training. Others welcome the intensity of interval training, and have no time in their week for endurance training. To paraphrase the Delphic Oracle, accommodate thy individuality.
You have to be breathing hard to get the benefit. For aerobic exercise, this can be a modest elevation that can be sustained for half an hour or more. For interval training, you want to be pushing to your limit for 1 to 4 minutes at a time. A popular form of interval training that many find more tolerable is to push even harder for half a minute at a time, repeated 5 to 10 times with brief breaks of 1 to 4 minute in between.
You can do anything that elevates your heart and breathing rates rapidly. Swimming the butterfly, sprinting, jumping “red hot pepper”, squat thrusts, calisthenics, pushups, pullups can all work. The elliptical trainer is my favorite instrument of torture.
Just a few years ago, weight training was associated with the vanity of body-builders, and health benefits were under-studied. Then doctors began to recognize the benefits ofweight-bearing exercise for osteoporosis. For 90-somethings, strength training increases independence, stair-climbing ability, walking speed, and slashes mortality risk associated with frailty. Now, far more general benefits are associated with training for muscle strength, and not just cardiovascular endurance. A Tufts University review found that
In addition, strength training also has the ability to reduce the risk of osteoporosis and the signs and symptoms of numerous chronic diseases such as heart disease, arthritis, and type 2 diabetes, while also improving sleep and reducing depression.
Again, you have two choices: many repetitions of modest challenges, or a few repetitions of exercises that are at the edge of your muscular strength. Particularly effective and particularly unpleasant seems to be that last effort in which you work your hardest and just can’t lift the weight (or whatever) one more time.
The grueling super-slow style of exercise consists in pulling or pushing or lifting or lowering over a period of about 10 seconds, so that instead of a sudden oomph of exertion (with follow-through from momentum), the muscles are engaged continuously over their full range of motion. Dr Mercola, the internet health guru, has just this year become an enthusiast of “super-slow” weight training. The Mayo Clinic offers a tentative endorsement.
3. Balance, coordination and reflex.
This is exercise for the nervous system more than the muscles. We lose motor skills and not just strength as we age, and with daily practice we hold on to these skills much longer.
Learning new skills is an anti-aging tonic for the brain.
On a cushioned floor, practice falling, and breaking the fall with your hands. Practice rolling into a tumble. Reflexes that you develop in this exercise will be there for you during those split seconds when you need them: tripping on a root in the woods, falling down the stairs, hitting a pothole at high speed on a bicycle.
Surfing, diving, skateboarding, unicycles, juggling, headstand, tightrope and other circus tricks can provide challenges for many years. My model for balance and coordination exercises is Stephen Jepson. In his 70s, he continues to walk on the tightrope and juggle while riding his unicycle. Video here.
You can’t become flexible by overcoming tightness with force. But if you move to the limit of your range of motion and consciously relax the muscles that are holding you back, the range of motion will slowly increase over time. Be patient, both in seconds and in months.
There is an ancient tradition in India and Tibet associating yoga with long life. Science may yet catch up.
At 95, Tao Porchon-Lynch continues to teach yoga in New York.
5. Keep moving
Even among people who exercise regularly, hours at a time spent sitting are anindependent risk factor for cardiovascular disease. Sitting at a desk also makes us dull and stifles creativity.
Walk up stairs instead of taking the elevator. Bicycle or walk to market and destinations in your neighborhood. Gradually expand your notion of “neighborhood”.
Forming new habits
Build activity into your life style. Change gradually, rather than making bold resolutions. Do what’s fun, and don’t let exercise be a chore. Jump on a trampoline. Jump in a lake. Dance. Skip rope. Volunteer to referee for the middle school soccer league. Kayak. Learn to skateboard, bongo board and unicycle.
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A major new review came out in JAMA last month summarizing 40 years of experiments with anti-oxidants and longevity. It was a meta-analysis of 78 different randomized, controlled trials between 1977 and 2012. Anti-oxidants don’t increase life span. There is a small increase in mortality associated with anti-oxidant vitamins E, C and beta carotene. I wrote a full post about this subject last year.
Anti-oxidant sales continue to boom, and “anti-oxidant” is on the label of thousands of health foods.
This article previously appeared in Josh’s blog here: http://joshmitteldorf.scienceblog.com/2013/11/06/forget-exercise/