Scientists may have figured out a strange new way to tell exactly how old you are.
How well you can balance on one leg can accurately indicate your age, according to a new paper in the journal PLoS ONE. This is because our muscles and nerves deteriorate with age, making it harder to stand on only one leg.
"This study underscores the significance of the unipedal balance test in monitoring elderly subjects in the community, regardless of sex," the researchers wrote in the paper. "The duration an individual, whether male or female, can maintain balance on one leg emerges as the most reliable determinant of aging, surpassing strength, gait, and other balance parameters."
As we get older, we naturally lose muscle mass in a process known as sarcopenia. Muscle fibers, especially the fast-twitch ones responsible for strength and power, shrink and decline with age, leading to a decrease in overall strength. Additionally, the body's ability to repair muscle damage after exercise or injury declines with age, making it harder to recover and build muscle.
"Aging causes a decline in mental and physical capacity. Gradual loss of physical activities is a characteristic of aging. Sarcopenia is one of the most devastating impacts of aging, resulting in the loss of muscle mass, strength, and function," the researchers wrote. "Adequate muscle strength, efficient gait, and good balance, which decline with age, are crucial contributors to independence and well-being."
In the paper, the researchers describe how they tested how aging was related to a wide range of abilities, including grip strength, knee strength, balance when standing on both legs, gait when walking, and balance on one leg only, in 40 participants. The one-legged test was carried out on the subject's dominant and non-dominant leg and tested for both how long the subject could stay on that leg and how much they were swaying.
They found that the length of time the subjects could balance on one leg deteriorated with age, and that there was no difference in this correlation between the sexes. However, they did find that the amount the subject swayed was not related to either age or sex.
"Unipedal stance time is a valid measure of frailty, independence, and fall status and proves to be a useful tool," the researchers said. "Despite its significance, decline in unipedal stance time has not been adequately studied in the context of aging."
Standing on one leg needs a range of sensory inputs as well as sophisticated muscle control, meaning that it can reliably show how a person's body is aging.
"Balance on one leg, as demonstrated in our study, undergoes the fastest decline in our healthy cohort, reflecting age-related declines in muscle strength similar to prior studies, and in the rapid coordination and integration of data by the central nervous system," the researchers said. "To the best of our knowledge, such a comparison is the first of its kind within the elderly population."
The study involved only 40 participants, however, so a larger sample size is needed to confirm a link between balancing ability and aging. Additionally, as this is an observational study, it cannot prove that one thing causes another, only that they are connected.
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References
Rezaei, A., Bhat, S. G., Cheng, C.-H., Pignolo, R. J., Lu, L., & Kaufman, K. R. (2024). Age-related changes in gait, balance, and strength parameters: A cross-sectional study. PLoS ONE, 19(10). https://doi.org/10.1371/journal.pone.0310764
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