Exercise, Add Intensity, Live To See Another Year

This blog was originally published in the New York Times.

The overarching message of this year’s exercise-related science was that physical activity, in almost any form and amount, changes the arc of our lives.

But much of this research also hinted that there may be something unique about pushing yourself at least a little extra that alters and ramps up the benefits of exercise, beginning deep within our cells.

Oh, and several studies also helpfully told us that hot baths are a fine idea for those of us who work out, even if the weather is warm.

But intensity was the theme of 2017. One of the first studies I wrote about this year detailed the career and physiology of Robert Marchand, a diminutive French centenarian who took up competitive cycling as a retiree and began setting age-group records.

But after a physiologist revamped his once-leisurely training, adding some strenuous pedaling, Mr. Marchand decisively bettered his own records and, at the age of 103, set a new world mark for the most miles pedaled in an hour by a centenarian.

His efforts help to belie a number of entrenched beliefs about older people, including that physical performance and aerobic capacity inevitably decline with age and that intense exercise is inadvisable, if not impossible, for the elderly.

Other studies this year reinforced the notion that age need not be a deterrent to hard exercise and that such workouts could be key to healthy aging. An animal study that I wrote about in July, for instance, found that frail, elderly mice were capable of completing brief spurts of high-intensity running on little treadmills, if the treadmill’s pace were adjusted to each mouse’s individual fitness level.

After four months of this kind of training, the exercised animals were stronger and more aerobically fit than other mice of the same age, and few remained physically frail. Perhaps most striking, “the animals had tolerated the high-intensity interval training well,” one of the scientists who conducted the study told me.

But of course, mice are not people. So it was another study this year that to my mind provided the most persuasive evidence that strenuous exercise alters how we age. In that study, which I wrote about in March (which became my most popular column this year), scientists at the Mayo Clinic compared differences in gene expression inside muscle cells after younger and older people had completed various types of workouts.

The greatest differences were seen in the operations of genes after people had practiced high-intensity interval training for 12 weeks. In younger people who exercised this way, almost 275 genes were firing differently now than they had been before the exercise. But in people older than 64, more than 400 genes were working differently now and many of those genes are known to be related to the health and aging of cells.

In effect, the intense exercise seemed to be changing muscle cells in ways that theoretically could affect biological aging.

At this point, I should probably pause and explain that intensity in exercise is a relative concept. The word intense can seem daunting, but in practice, it simply means physical activity that is not a cinch for you.

For research purposes, intensity is based on percentages of someone’s heart rate maximum. But you and I can ignore these technicalities and pay attention to how we feel. Many scientists have told me that exercise is considered easy if you can talk and sing while participating in it.

During relatively moderate exercise, singing becomes difficult.

And during intense exercise, you will find it difficult to speak without gasping.

But, again, intensity is relative. If you have barely exercised in recent years, five minutes of climbing stairs will constitute an intense — and effective — workout.

If, on the other hand, you regularly stroll during the week, you might consider increasing the pace of those walks for a few minutes at a time, until you no longer can easily converse. The latest science suggests that your cells will thank you.

And afterward, other science says, reward yourself with a warm soak. Several ingratiating studies this year indicated that luxuriating in warm water aids in recovery from strenuous exercise and also, surprisingly, helps us to acclimate to hot-weather workouts.

But as always, the most compelling exercise-related research this year reminded us that activity of any kind is essential for human well-being. One of my favorite studies of 2017 found that people reported feeling happiest during the day when they had been up and moving compared to when they had remained seated and still.

Another memorable study concluded that, statistically, an hour spent running could add about seven hours to our life spans. These gains are not infinite. They seem to be capped at about three years of added life for people who run regularly.

But the results have inspired me. I trained for and ran a half marathon in 2017 and will run another in 2018. I am not fast. But I aim to be persistent. If Mr. Marchand can gain fitness and speed after turning 100, why should not those of us with still a half-century or more to spare? Happy New Year, everyone.