When it comes to exercise, the general wisdom is that as you age your workouts should diminish in both impact and intensity. The former is meant to protect your joints, but the reasoning for the latter is less clear. To keep your heart rate from spiking? To preserve diminishing stores of energy? Because you’re simply not as young as you once were?
As it turns out, decreasing the intensity level of exercise might not be a way to care for your aging body. The New York Times reported on a study done by the Mayo Clinic about the effects of exercise on cellular mitochondria, which produce energy and are known to diminish in both number and vigor as we age. The study monitored the cellular changes in four groups of volunteers, ranging in age from younger than 30 to older than 64. One group did a heavy weight-lifting regimen, one group did moderate exercise and lighter weight-lifting, one group did high-intensity interval training, and the control group undertook no exercise whatsoever. The results were both surprising and dramatic, suggesting that the way we’ve been modifying exercise as we age might completely counterproductive.
Among the younger subjects who went through interval training, the activity levels had changed in 274 genes, compared with 170 genes for those who exercised more moderately and 74 for the weight lifters. Among the older cohort, almost 400 genes were working differently now, compared with 33 for the weight lifters and only 19 for the moderate exercisers. Many of these affected genes, especially in the cells of the interval trainers, are believed to influence the ability of mitochondria to produce energy for muscle cells; the subjects who did the interval workouts showed increases in the number and health of their mitochondria — an impact that was particularly pronounced among the older cyclists.
That is a crazy difference, particularly between high intensity and moderate exercise. For years we’ve been assured that moderate exercise is just as good as high-intensity exercise, but tons of recent studies are proving the exact opposite. And while lifting heavy is important for increasing bone density as you age, this study shows that high-intensity exercise is absolutely vital for maintaining cellular health. In fact, the changes produced by high-intensity interval training seem to have a corrective effect on aging mitochondria.
It’s almost like high-intensity exercise keeps us young, much like the fabled Fountain of Youth … though perhaps with less idyllic lounging and more red-faced sweating. I know that at 33, having finally embraced the pain and pleasure of high-intensity exercise, I feel younger than I did for all of my 20s. In fact, my high school cheerleading coach told me yesterday that she wishes I had been in this good shape when I was cheerleading for her 15 years ago.
I get the resistance to intense exercise, I really do. I spent years doing pilates videos and taking long, slow runs because intense exercise is, quite simply, unpleasant. It can even be alarmingly unpleasant at first, raising your heart rate to levels that feel dangerously high and causing you to pant and gasp for air.
But provided your heart is healthy when you start high-intensity interval training, that severe discomfort fades fast as your mind and body readjust to new demands. Eventually, you’ll even start to enjoy being able to throw yourself into intense workouts (don’t roll your eyes, it’s true!). And it won’t be long before you’re running up stairs without batting an eye and beating your kids (or grand-kids) at freeze tag … all while feeling (and at a cellular level, being) younger than you have in years. So throw out your yoga mats, free yourself from the tyranny of brisk walks, and start sweating like you mean it!
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