For the past 10 years (and change), I have been covering exercise science in this column. During that time, I have seen interest in high-intensity exercise soar and enthusiasm for barefoot running fizzle. We have learned contracting muscles talk to baby neurons, creativity blooms from walking, a minute of exertion can be ample, aging is elastic and a chubby dog may be our best exercise motivator.

With 2019 ending, I thought it worthwhile to look back at some of the persistent themes, revelations and surprises from the past decade in fitness.

Perhaps most obviously, this has been a decade of greatest HIITs, with multiple studies and subsequent columns reiterating that super-short, strenuous workouts — known as high-intensity interval training — improve fitness and health to about the same extent as much longer, more moderate exercise. Since 2010, I have covered seven-minute, four-minute, one-minute, 20-second and 10-second interval routines, with each workout’s declining length increasing its allure. For many of us, the exercise of choice may be the briefest.

At the same time, though, a wealth of other studies this decade underscored that gentle exercise is also meaningful, even if it barely qualifies as exercise. In one of my favorite studies from this year, researchers found that older women who regularly strolled about two miles a day, or a little more than 4,000 steps, lived longer than women who covered only about 2,000 steps, or a mile. Going that lone extra mile altered how long and well women lived.