Inactive men may have a substantially increased risk for broken bones of all kinds, and especially for hip fractures, a new Swedish study has found. Even after controlling for health and behavioral variables, researchers reported, sedentary men were more than one-and-a-half times as likely as active ones to suffer a broken bone, and more than two-and-a-half times as likely to break a hip.

Although they are unsure of the mechanism, the authors theorise that exercise may work by increasing skeletal strength and muscle mass, and improving balance. The active men in the study did three or more hours a week of intense physical activity.

Previous studies have linked exercise with bone health in women. But until now the evidence for men has been mixed. The researchers studied health records of 2,205 men beginning at age 49 to 51, and then followed them for up to 35 years, during which 482 men had at least one fracture. The men were examined again at ages 60, 70, 77 and 82. At the end of the follow-up period, 896 of the men were still living.

At each of the five interviews, the scientists posed the same questions about watching television, engaging in sedentary activities, walking or cycling for pleasure, and engaging in sports either recreationally or competitively. They also administered exercise tests and performed muscle biopsies to measure physical fitness, confirming that the men who reported higher levels of exercise were in fact more fit. By linking records with job titles, they were also able to include information on physical activity at work.

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