Despite how strongly exercise is promoted as “good for you,” an estimated 82.4 million Americans remain inactive, according to the 2018 Physical Activity Council Participation Report, an annual summary of findings about the effect of exercise on the health of Americans.

Some scientists, such as Mark Tarnopolsky, MD, PhD, a professor at McMaster University, in Hamilton, Ontario, who treats children with genetic diseases, have focused on proving that the benefits of physical activity are real, measurable and quick. “The most effective therapy available to my patients right now is exercise,” he told Time magazine.

Last year, researchers published a review in the medical journal Current Opinion in Cardiology that demonstrated marked health benefits were achievable with even small amounts of physical activity.

Studies show exercise can help even those who were previously advised not to work out because they are ill. Research has found that becoming or remaining active can be effective therapy for people with various chronic conditions, such as stroke and muscular dystrophy. In addition, working out can alleviate depression, improve memory and accelerate learning.

What’s more, additional findings show that just moving about—even for short periods each week—boosts skin health, slows aging and may increase life span by up to five years.

Maybe that’s why many experts feel exercise is the best medicine of all.