June 18, 2024

In a year filled with Covid-related hopes, setbacks, advances and losses, the most vital exercise science of 2021 provided a reminder that for many of us, our bodies and minds can strengthen, endure and flourish, no matter our circumstances. If we move our bodies in the right ways, a growing body of evidence suggests we might live with greater stamina, purpose and cognitive clarity for many years to come. And it may not take much movement.

In fact, some of the year’s biggest fitness news concerned how little exercise we might be able to get away with, while maintaining or even improving our health. A study from January, for instance, showed that just five minutes of intense calisthenics substantially improved college students’ aerobic fitness and leg strength. Another series of studies from the University of Texas found that four seconds — yes, seconds — of ferocious bicycle pedaling, repeated several times, was enough to raise adults’ strength and endurance, whatever their age or health when they started.

Even people whose favorite workout is walking might need less than they think to reach an exercise sweet spot, other new research suggested. As I wrote in July, the familiar goal of 10,000 daily steps, deeply embedded in our activity trackers and collective consciousness, has little scientific validity. It is a myth that grew out of a marketing accident, and a study published this summer further debunked it, finding that people who took between 7,000 and 8,000 steps a day, or a little more than three miles, generally lived longer than those strolling less or accumulating more than 10,000 steps. So keep moving, but there’s no need to fret if your total doesn’t reach a five-figure step count.

Of course, exercise science weighed in on other resonant topics this year, too, including weight. And the news there was not all cheering. Multiple studies this year reinforced an emerging scientific consensus that our bodies compensate for some of the calories we expend during physical activity, by shunting energy away from certain cellular processes or prompting us unconsciously to move and fidget less. A study from July, for example, that examined the metabolisms of almost 2,000 people concluded that we probably compensate, on average, for about a quarter of the calories we burn with exercise. As a result, on days we exercise, we wind up burning far fewer total calories than we might think, making weight loss that much more challenging.