Middle-aged men who maintain their muscle mass may lower their risk of heart disease as they get older, a new study suggests.

Beginning in the mid-30s, muscle begins to decline by about 3% each decade. Previous studies found that muscle mass is associated with heart attack/stroke risk, but those studies focused on people with heart disease.

In this new study, the researchers wanted to examine if muscle mass in middle age might be associated with long-term heart health in people without heart disease.

The study included more than 1,000 men and women, aged 45 and older, who were followed for 10 years. During that time, 272 participants developed heart disease, including stroke and minor stroke.

People with the most muscle were 81% less likely to develop heart disease than the least muscular. Those with the most muscle had the lowest rates of risk factors such as high blood pressure, diabetes and obesity, the investigators found.

Further analysis showed that muscle mass was significantly linked to lower heart disease risk among men, but not women.

Possible reasons for this gender disparity include age-related hormonal differences and the fact that the men had more muscle to start with, according to the study authors. Their findings were published online Nov. 11 in the Journal of Epidemiology & Community Health.

Because this was an observational study, it can't establish cause and effect. Even so, the findings "point to the importance of [skeletal muscle mass] preservation in relation to [cardiovascular disease] risk," the authors wrote in the report.

Regular physical activity, including resistance training, and a diet rich in protein may help preserve lean muscle mass as people get older, the researchers suggested.

Demosthenes Panagiotakos, a professor in the School of Health Science and Education at Harokopio University in Athens, Greece, led the study.