BUFFALO, N.Y. – You don't need to look like a bodybuilder, but for healthy aging, maintaining muscle strength is likely just as important as getting enough aerobic activity.
That's according to the findings of a University at Buffalo-led study of more than 5,000 women between the ages of 63 and 99 published Feb. 13 in JAMA Network Open . It found that women with higher levels of grip strength and those who completed five unassisted sit-to-stand chair raises in the fastest amount of time had significantly lower death risk over an eight-year follow-up.
The lower mortality rates were evident even after accounting for physical activity and sedentary behavior, as measured by accelerometer data, gait speed (an indicator of cardiovascular fitness) and C-reactive protein, a blood biomarker of inflammation believed to be a major driver both of losing muscle function and premature death.
In fact, for every 7 kilograms of grip strength, there was, on average, a 12% lower mortality rate. When it came to chair stands, moving from the slowest time to the fastest time in 6-second increments, researchers saw a 4% lower mortality rate.
Grip strength and chair stands are two tests commonly used to determine strength levels among older patients in a clinical setting.
"If you don't have enough muscle strength to get up, it is going to be hard to do aerobic activities, such as walking, which is the most commonly reported recreational activity in U.S. adults ages 65 and older," says study lead author Michael LaMonte, PhD , research professor of epidemiology and environmental health in UB's School of Public Health and Health Professions.
"Muscular strength, in many ways, enables one to move their body from one point to another, particularly when moving against gravity," LaMonte adds. "Healthy aging probably is best pursued through adequate amounts of both aerobic and muscle-strengthening physical activities. When we no longer can get out of the chair and move around, we are in trouble."
The study is the largest to date to evaluate muscle strength in relation to longevity in women over 60, LaMonte says, adding that most previous large-scale epidemiologic studies did not have the measures of physical activity, inflammation and cardiovascular fitness used for this study. Those measures helped LaMonte and colleagues simultaneously account for these important mortality factors in order to better isolate the association with muscular strength.
"We also showed that differences in body size did not explain the muscular strength relationship with death," he says. "When we scaled the strength measures to body weight and even to lean body mass, there remained significantly lower mortality."
Even among women who did not meet current physical activity guidelines for adults — 150 minutes of moderate intensity aerobic activity — those with higher muscular strength had significantly lower mortality. LaMonte says that's "a major advancement" to the available evidence supporting the inclusion of muscle strength in public health messaging on physical activity, especially in older adults — a particularly important age group.
"Because women ages 80 and older are the fastest growing U.S. age group, the importance of monitoring and maintaining muscular strength will have huge public health implications in the coming decades," he says.
There are many ways to build muscle, including using conventional free weights and dumbbells or weight machines, or bodyweight exercises such as modified push-ups, wall presses and knee bends.
LaMonte adds that a trip to the gym may not even be necessary. "Even using soup cans or books as a form of resistance provides stimulus to skeletal muscles and could be used by individuals for whom other options are not feasible."
Older adults, in particular, should consult with their health care provider about the safety of beginning muscle-strengthening exercises, LaMonte notes, adding that those not familiar with these types of activities should consult with a physical therapist or exercise specialist to ensure safety as well as achieving targeted strength goals.
Co-authors on the paper include researchers from the National Cancer Institute, University of California San Diego, Texas A&M University, Brown University, Stanford University and Fred Hutch Cancer Center.
