When we talk about cardio, we are talking about aerobic exercise—that is, sustained activity that elevates your heart rate into a range at which you’re training your heart. “Cardiovascular fitness,” sometimes used interchangeably with “cardiorespiratory fitness,” isn’t a term you hear thrown around much in yoga class. But maybe it should be. Measured by how efficiently the heart moves blood—and therefore oxygen—to the muscles, cardiovascular fitness is considered one of the surest routes to leading a long, healthy life. The heft of scientific evidence shows that fitter people are less likely to suffer from heart disease, diabetes, obesity, and certain cancers. Studies link cardio workouts with better cognitive function, sharper focus, and possible protection against the short-term memory loss that often comes with aging.