Strength Is Key to Function, Study Finds
Not sticking with exercises to build strength may leave a person too weak to do what has to be done around the house, researchers say.
“I am convinced that strength is important for preservation of function,” said researcher Steven N. Blair of the Cooper Institute for Aerobics Research in Dallas.
And the limitations commonly associated with the aged can afflict the out-of-shape middle-aged, said the study by Blair and his colleagues in the American College of Sports Medicine journal, Medicine and Science in Sports and Exercise.
The researchers followed 3,069 men and 589 women, ages 30 to 82, who were examined at Cooper Clinic between 1980 and 1989. The participants had to be free of any history of heart attack, stroke, diabetes, high blood pressure and cancer at that time.
On a treadmill test, the participants had to exercise hard enough to reach at least 85% of the maximal heart rate predicted for people of their age. They also were given tests of upper and lower body strength, and were rated from 0 to 6 based on the results. Scores of 5 and 6 were grouped as high strength.
After an average of five years, the participants responded to a mail-back questionnaire on their abilities to do recreational, household and personal care activities, ranged from cooking and getting dressed to scrubbing floors and walking up 10 stairs without resting.
Those who had tested in the high-strength group were less likely than those with low strength to report later any type of functional limitation, the researchers found. In men, only 3.2% of the high-strength group reported a limitation, compared with 8.3% of those with lower strength. In women, 4.7% of the high-strength group and 13.5% of those with lower strength reported a limitation.
Although older people most commonly have limitations, “the association between muscular strength and endurance and the subsequent prevalence of functional limitations indicates that this relationship persists even among middle-aged adults,” the report said.
Aerobic endurance is not the only way to stay active; strength training has a role too, the study concluded.
But the researchers noted their work left unanswered questions.
The scientists could not be sure the participants had no limitations at the start of the study. But the researchers considered the participants’ high scores on the treadmill test and their freedom from heart disease and other debilitating conditions as signs the subjects were healthy at the start.
The researchers also could not be sure the participants who were strong at the start kept up, in the intervening years, the activity levels that help people to stay strong. But Blair surmised they probably did make activity a habit.
The study offers new encouragement for sedentary people not to give up on the possibility of starting an exercise program and benefiting from it, said Miriam Nelson, director of the Center for Physical Fitness at Tufts University.
“The real point of the study and other recent research is that no matter what age you are, starting and sticking with it can have very profound effects on your function as you grow older,” said Nelson, who was not involved in the study.
People in their 50s and 60s who take up exercise can reverse much of the loss that had been blamed on aging, said Nelson, author of the book “Strong Women Stay Young.” Even people in their 90s can make surprising strength gains, she said.
Exercise cannot ward off all the age-related changes in muscle, but it can control the damage.
Researchers increasingly believe much of the muscle loss that middle-aged people believe to be caused by age is really caused by inactivity. It can be reversed by strength training, which can range from lifting weights at a gym to carrying around milk jugs or doing home improvement projects.
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On the Net: Cooper Institute site: https://www.cooperinst.org/
National Institute on Aging health tips site: https://www.mayohealth.org/mayo/9810/htm/aging_sb.htm
