By GRETCHEN REYNOLDS New York Times
The big story in exercise science this year was the super-short workout.
In one particularly useful study from May, scientists found that three brief sessions per day of interval-style exercise — consisting of one minute of brisk walking followed by another minute of strolling, repeated six times — allowed people at risk of diabetes to control their blood sugar better than a continuous 30-minute walk.
Just as important, these short “exercise snacks,” as the scientists called the condensed sessions, were more popular with the study’s participants than the single, longer walk, the scientists reported. They liked finishing quickly.
That sentiment likewise explains the popularity of the “Scientific 7-Minute Workout,” which I first wrote about in 2013 and updated this fall with an advanced version and a related app. Similarly, many of you were intrigued by a July study detailing how running as little as five minutes a day might add years to someone’s life span. “Most people can fit in five minutes a day” of exercise, one of the study’s authors told me.
But should even that time commitment seem excessive, scientists obligingly developed and tested a one-minute workout this year, with three 20-second intervals of very hard exercise leading to robust improvements in the endurance and health of the study’s overweight, out-of-shape volunteers.
There is naturally a catch to such truncated workouts, however. In each of these studies, the exertion involved was intense. The volunteers panted and strained, albeit briefly. Their strenuous exercise seemed to invoke “more potent” physiological responses than gentler activity, one of the researchers involved in the exercise-snacking study said.
A nifty June study helps to explain why. In that experiment, mice that were pushed to run hard on running wheels developed distinctly different biochemical responses within their muscle cells than other animals and these differences translated into larger, healthier muscles. The study’s lesson, its lead author concluded, is that sometimes you need to “get out of your body’s comfort zone.” But only, thankfully, for a minute or five.
While studies showing how little exercise you can complete and still become healthier, stronger and fitter may be — let’s be honest — among the most beguiling exercise news of the year, many other fitness-related themes emerged in 2014, as a look back through this year’s Phys Ed columns reminded me.
Scientists advanced, for instance, our understanding of the effects of exercising — and not exercising — on the mind and brain. Several different studies found that exercise significantly improves the brain health of people with a genetic predisposition to Alzheimer’s disease and also, encouragingly, lessens healthy, middle-aged people’s risks of suffering from what one scientist described to me as “a C.R.S. problem,” or Can’t Remember Stuff.
Another study explored how exercise can improve mood, with Swedish researchers showing that, in mice, a substance produced abundantly in the bodies of both mice and men during exercise crosses the blood-brain barrier and buffers brains against stress and depression.
And, in perhaps the most novel exercise-neuroscience experiment this year, researchers explored how sitting may affect the brain, by having one group of rats remain sedentary while others ran. The sedentary rats soon displayed changes in the shape and function of certain neurons in their brains, while the running rats showed no such changes. The neurons involved play a role in how well the body regulates blood pressure, so the researchers concluded that not exercising had remodeled the animals’ brains in ways that undermined their health.
Meanwhile, plenty of other studies this year underscored how wide-ranging the benefits of exercise really are. In various experiments, physical activity was found to lessen and even reverse the effects of aging on human skin; protect against age-related vision loss; improve creativity; lower people’s risk of developing heart disease even if they had multiple risk factors for the condition; increase the numbers of good bacteria in athletes’ guts; raise exercisers’ pain tolerance; and alter, in desirable ways, how our DNA works.
Being in good shape also, in a sense, keeps us young, according to a large-scale study published in October. Fit people were biologically younger than others of the same chronological age, the study concluded, and generally lived longer. “There is a huge benefit,” the study’s senior author told me, “larger than any known medical treatment, in improving your fitness level to what is expected for your age group or, even better, to above it.”
But the benefits of exercise are not limitless, as science gently reminded us this year. Working out spurs many people to gain weight, primarily in the form of body fat, a pitiless but important October study showed. It also can be harmful to the teeth, if the exercise is prolonged and strenuous. And if practiced in a gym, exercise may expose us to more indoor pollution than many of us might have expected.
Luckily, this exposure will be minimal for those of us embracing the one-minute workout.