1. High Blood Pressure

The blood pressure mistake your doctor may be making: Sticking with lifestyle changes when you need drugs.

The evidence shows that it’s safe to try to bring down mildly elevated blood pressure by eating better and exercising. But if your numbers are even moderately high, the advice is unequivocal: Your doctor must prescribe drugs because uncontrolled high blood pressure puts you at risk for a deadly heart attack or stroke.