Medically Reviewed “Fitness snacking” with brief bursts of exercise can help you reestablish a workout routine, says an expert. iStock Has the COVID-19 pandemic put you in a workout slump? If your fitness habits aren’t what they used to be, rest assured — you’re in good company. A growing body of evidence shows that the pandemic has profoundly changed how much people exercise, not only in the United States but around the world. In a study published in November 2020 in the Annals of Internal Medicine, researchers found that, based on more than 19 million smartphone-based, step-counting measurements taken from January 19 to June 1, 2020, physical activity levels dropped dramatically in many countries after the pandemic struck.