may have unique payoffs, compared with less strenuous exercise. In a study that I wrote about a few weeks ago, for instance, people who walked briskly, at a pace of 17 minutes per mile or less, generally lived longer than those men and women who strolled during their walks, at a pace of 20 minutes per mile or slower, although the study was not designed to determine why the intensity of the exercise mattered.
And in September, I wrote about two studies showing that strenuous exercise blunted volunteers’ appetites after workouts more effectively than longer sessions of easy exercise did. The studies were small, though, and involved only young-ish, overweight men. Whether the results are applicable to other people, including those of us who are not male, requires additional experiments.
Meanwhile, other studies that I wrote about this year emphasise how pervasive the impacts of any amount and type of exercise can be. One of my favorite experiments of 2013 detailed how rodents that ran on wheels for several weeks responded far better to stressful situations than sedentary animals, in large part, it seems, because their brains contained specialised cells that dampened unnecessary anxiety. At a molecular level, the runners’ brains were calmer than those of their sedentary lab mates.
But perhaps the most remarkable studies of the year examined the effect of exercise on our DNA. In several experiments, which I wrote about in July, scientists found that exercise reshapes genes in human cells, changing how atoms attach to the outside of individual portions of our DNA. As a result, I wrote, the behavior of the gene changes.
In one of the studies, researchers found that six months of moderate exercise profoundly remodelled genes related to the risk for diabetes and heart disease. But for those of us too impatient to wait six months, the other study found that a single session of bike riding altered genes in volunteers’ muscle cells. The effects showed up whether the pedaling was easy or strenuous, but, in line with so much of this year’s exercise science, were more pronounced when cyclists rode vigorously.