SÃO PAULO, Brazil — Here’s a reason to keep pumping that iron in our senior years: a study of men and women over 65 shows that the risk of death by any cause rises dramatically in people with low muscle mass in their arms and legs.
Researchers at the University of São Paulo’s Medical School say the findings were particularly significant for women. A woman with weak arm and leg muscles — also known as appendicular muscles — is 63 times more likely to die, compared to 11.4 times for a man.
For the study, the authors measured bone density and body composition in 839 men and women. They say that evaluating appendicular muscles is effective in predicting the longevity of individuals over 65 years of age. That’s because this group of muscles moves our appendages and extremities and plays a crucial role in stabilizing the hips and shoulders.
“We evaluated the body composition of this group, focusing on appendicular muscle mass, subcutaneous fat and visceral fat. We then sought to determine which of these factors could predict mortality in the ensuing years. We concluded that the key factor was the amount of appendicular lean mass,” says principal investigator Rosa Maria Rodrigues Pereira, Full Professor and Head of Rheumatology at the university, in a release.
By The Numbers: How Researchers Linked Muscle Mass To Death
The researchers recorded body composition using dual-energy X-ray absorptiometry (DXA). In all, 323 participants were men (39%), and 516 were women (61%). The rate of low muscle mass was about 20% for both men and women.
Age-related sarcopenia, or the gradual loss of muscle mass and quality while aging, is a major problem in Brazil’s elderly population. About 46% of Brazilians over 80 years old have the disease, according to the Brazilian Association of Geriatrics and Gerontology. When combined with osteoporosis, sarcopenia makes older men and women more prone to falls, fractures, and serious physical injuries. Low bone mineral density, especially in the femur, is linked to earlier death in elderly people, according to previous research.
Researchers also analyzed blood samples and the responses participants supplied to questionnaires evaluating diet, physical activity, alcohol consumption, smoking, and whether they had chronic diseases such as diabetes.
About 16% of the participants after the four-year study period had died. Forty-three percent died because of cardiovascular problems. Overall, the mortality rate during the study was 20% for men and 13% for women.
Those who passed away were older than the other participants, and exercised less. They also had a higher prevalence of diabetes and cardiovascular problems. The women who died during the study had lower BMI while the men were more likely to suffer falls.
The Verdict: Regular Exercise, Pumping Iron May Be Key To A Longer Life
Low muscle mass showed the strongest link to death risk for women, while visceral fat — or the fat encircling the major organs — played a greater role for men. In men, each six-centimeter-squared increase in abdominal fat doubled risk of death. Interestingly, a high proportion of subcutaneous fat (under the skin) appeared to have a protective effect in men.
Muscle mass loss occurs naturally after the age of 40 and accelerates after the age of 50, when people lose between one and two percent of muscle mass each year. Sedentary habits, a protein-poor diet, hospitalization, and chronic diseases accelerate the loss of muscle mass.
Sarcopenia is preventable and can be reversed with increased physical exercise and better attention to protein ingestion.
The study is published in the Journal of Bone and Mineral Research.