Physical abilities fade as we age, but many of us like to think that won’t be an issue until we’re well into our golden years.
According to a new study, however, fitness and strength begin to dwindle as early as age 35, regardless of exercise habits. This is followed by a gradual decline that accelerates with age.
While this fate may be unavoidable, that doesn’t mean it’s out of our hands. Even if physical activity won’t help us delay our peak, it can make a difference in how rapidly our abilities deteriorate, the study suggests.
Aging involves a progressive decline in skeletal muscle, which can noticeably manifest for some people in their 60s, sometimes limiting mobility.
Previous research on elite athletes has shown that, despite continuous training, physical performance typically peaks by about age 30. This suggests the mechanics behind age-related muscle loss could already be at work decades before they become clinically significant.
There are advantages to studying physical abilities in athletes, such as data availability and lack of interference by sedentary lifestyles, but there is also the “obvious disadvantage” that elite athletes may not be representative of the general population, the authors note.
For the new paper, researchers conducted a population-based longitudinal study in hopes of measuring the physical capacity of the general population from adolescence to older age.
Research on this subject has typically relied on cross-sectional studies, which analyze data from a population at a specific point in time. Longitudinal studies can therefore provide valuable perspectives on how variables may change over a period.
The researchers used data from the Swedish Physical Activity and Fitness (SPAF) cohort study, a longitudinal study that has been following several hundred participants in Sweden since 1974, when they were 16 years old.
The SPAF includes strength and fitness data from these same people at five intervals in the last five decades (ages 16, 27, 34, 52, and 63), offering a unique opportunity to measure changes in physical abilities over half a century.
Cross-sectional studies seem to have underestimated the age-related decline in physical capacity, the researchers report, but their findings support existing evidence that it affects men and women similarly.
For both sexes, muscular endurance and estimated maximal aerobic capacity peaked between ages 26 and 36 before gradually declining, first by 0.3 percent to 0.6 percent per year, and later by up to 2.5 percent per year, with no sex difference in the rate of decline.
There was a difference in muscle power, with men and women peaking at ages 27 and 19, respectively. Their muscle power then faded at similar rates, initially decreasing by 0.2 percent to 0.5 percent per year, and later escalating to an annual decline of 2 percent or more. By age 63, participants’ overall drop from their peak physical capacity ranged from 30 percent to 48 percent.
There is good news. While we may be unable to dodge or delay our physical decline, we can reduce its speed with regular exercise, the authors report.
“Individuals who were physically active in their leisure time at age 16 maintained higher aerobic capacity, muscular endurance, and muscle power throughout the observation period,” they write.
This highlights the importance of promoting physical activity to teenagers and young adults, but that message is helpful no matter how old you are. Participants who became more active in adulthood still managed to improve their physical capacity by around 10 percent, the study found.
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“It is never too late to start moving. Our study shows that physical activity can slow the decline in performance, even if it cannot completely stop it,” says lead author Maria Westerståhl, lecturer in the Department of Laboratory Medicine at the Karolinska Institute.
“Now we will look for the mechanisms behind why everyone reaches their peak performance at age 35, and why physical activity can slow performance loss but not completely halt it,” Westerståhl says.
The study was published in the Journal of Cachexia, Sarcopenia and Muscle.