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Maintaining muscular strength could be vital for older women to age healthily, protecting them from death even when their fitness levels are below par.
The findings, in JAMA Network Open, support guidelines that encourage muscle strengthening activities to age well and live longer.
Two common measures of muscular strength, that can easily be assessed in a clinical setting, were linked with a decreased risk of death among women aged 63 to 99 years in the study.
The associations remained even after accounting for physical activity, sedentary time, walking speed, and inflammation.
“Notably, muscular strength was associated with lower mortality even in women who did not meet guideline-recommended amounts of aerobic physical activity,” reported researcher Michael LaMonte, PhD, from the University at Buffalo, and co-workers.
The team notes that, by 2050, women aged 75 years and older will constitute the largest age subgroup in the U.S.
Skeletal muscle strength declines rapidly during adulthood, yet remains integral to maintaining functional independence, averting hospitalizations, and improving quality of life.
U.S. guidelines recommend skeletal muscle strengthening activities at least two days per week to achieve systemic and functional health benefits.
LaMonte and fellow investigators examined how muscle strength—assessed from dominant hand-grip strength and the time taken to complete five unassisted chair stands—related to mortality among in 5472 older women.
All participants were enrolled in the Objective Physical Activity and Cardiovascular Health in Older Women (OPACH) study, which is ancillary to the Women’s Health Initiative (WHI). Their mean age was 78.7 years, around half were White, a third were Black, and about a sixth of Hispanic ethnicity.
During a mean follow up of 8.4 years, 1964 of the women died.
There was a significant inverse trend in mortality as grip strength increased, with the third and fourth highest quartiles having hazard ratios of 0.85 and 0.67, respectively, compared with the lowest quartile.
Similar results were seen for chair stand time, with increasing quartiles showing significant decreases in the risk of death and corresponding hazard ratios of 0.79, 0.76 and 0.63 compared with the lowest quartile.
Adjusting for accelerometer-measured physical activity and sedentary time reduced these associations, although the results remained statistically significant.
Similar inverse associations were observed when controlling for walking speed, which was as a proxy of cardiorespiratory fitness, and the inflammatory marker C-reactive protein.
The correlation between grip strength and chair stand time was relatively small, with less than two percent shared variation, the authors noted, suggesting the two measures were largely assessing different constructs.
They concluded: “Our finding supports current national recommendations that promote participation in muscle strengthening activity for optimal aging and longevity.”
