Do it even if you're thin. Lounging on the couch instead of moving your body is deadly for the vascular system — whether you're overweight or not. “Just because you're not fat doesn't mean you don't have to exercise,” Goodman says. Two studies published in the Journal of the American Medical Association found that being inactive was a stronger predictor of coronary heart disease, heart attack, and stroke in women than being obese. Another study found that women who exercised regularly but were obese had almost twice the risk of death compared with women who were both active and lean. What's the takeaway? A sedentary lifestyle and excess pounds are a double whammy for the vascular system.