Pumping iron can help build muscles, boost metabolism, maintain strong bones and more. But is it safe for seniors’ hearts? French researchers who studied 65 healthy elderly men and women say the answer is yes—as long as seniors lift with care and breathe properly. The investigators instructed their study subjects, who ranged in age from 65 to 80, to inhale as they lowered a weight and to exhale as they lifted. Although participants’ heart rates and blood pressures went up while they performed the strengthening exercises, levels of cardiac troponin I, a marker for heart attack, held steady—a sign that the heart was not in jeopardy. Still, anyone who is considering beginning a weight-lifting regimen should consult his or her doctor first.