Myth #7: Strength training builds muscle and bone but does nothing for the heart.

Truth: Strength training plus aerobic exercise may be the ideal exercise regimen not only for the waistline but also for the heart. One analysis of 11 clinical trials found that strength training can reduce levels of LDL cholesterol, the artery-clogging kind (though it has little effect on HDL cholesterol, the artery-clearing kind). Aerobic exercise has a complimentary benefit: It improves HDL but does little for LDL. Further, some studies suggest that strength training, like aerobic exercise, may help reduce blood pressure. (But check with your doctor for guidance before starting a muscle-building program if you have hypertension, since straining can temporarily increase blood pressure.) One final benefit: By fortifying the muscles, strength training reduces the likelihood that sudden or unaccustomed exertion, such as moving furniture or shoveling snow, will trigger a heart attack.