Mortality risk lower in older women who maintain muscle strength

Higher muscular strength is associated with a lower mortality risk in women ages 63 to 99, regardless of physical activity level, according to the results of a recent study published in Public Health.

During the study, called the Objective Physical Activity and Cardiovascular Health in Older Women study, a team of researchers, including corresponding author Michael J. LaMonte, Ph.D., M.P.H., Department of Epidemiology and Environmental Health, School of Public Health and Health Professions, University at Buffalo, studied the physical performance of 5,472 women ages 63 to 99, with an average age of approximately 79. Participants were followed up with for eight years. At the study’s end there were 1,964 deaths recorded, which means there was a large dataset to explore the relationship between muscle strength and longevity.

LaMonte and his team tested hand grip strength and chair stand performance specifically. Handgrip strength was assessed using a dynamometer, measuring the dominant hand’s force. Chair stand performance was measured by timing how quickly participants could stand up from a seated position five times without assistance, which is a standard test of lower-body strength and function. The physical performance tests were followed by seven days of accelerometer wear to record additional information about movement frequency and intensity.

The study found a clear and consistent link between greater muscle strength and lower mortality risk. Women in the highest grip strength group had a 33% lower risk of death compared with those in the weakest group, even after adjusting for age, race, lifestyle factors, and existing medical conditions. Furthermore, for every approximately 15 lb. increase in grip strength, the risk of death decreased by 15%.

Similarly, better performance on the chair stand test was associated with a 37% lower mortality risk in the fastest group versus the slowest. Every 6-second improvement in chair stand time corresponded to a 9% reduction in mortality risk.

Additionally, the correlation between grip strength and chair stand time was only 2%, which suggests the two measures predict longevity in separate ways.

Aerobic exercise has traditionally been the focus of exercises for longevity, but these recent results show that strength levels may be more important than previously believed. For example, longevity was still higher in women who did not meet the required aerobic exercise recommendation but had greater muscular strength.

“Our finding supports current national recommendations that promote participation in muscle strengthening activity for optimal aging and longevity,” LaMonte and his team write in the study. “To improve guideline recommendations, future research should better characterize the type and amounts of muscular strengthening activity associated with more specific outcomes across the health span.”

Muscle strength declines rapidly during adulthood but is essential if patients are to maintain their health and independence. This is especially pertinent because by 2050, women ages 75 and older will be the largest age subgroup in the United States.

The Centers for Disease Control and Prevention currently recommends that individuals over the age of 60 supplement regular aerobic exercise with at least two days of muscle strengthening exercises per week. These include wall pushups and resistance band pulls.