Balance, agility, and leg strength predicted survival in older adults better than cardiovascular and pulmonary endurance tests. The results of a new study were published in JAMA Network Open.
Older adults who could stand on one leg the longest were more likely to be alive seven years later. The same was true for those who could stand up from a chair, walk 2.44 meters around a cone, and sit back down the fastest.
In clinics that measure physical fitness, heart and lung function are typically measured. But in this study, this test was only the fourth most important predictor of survival.
Li-Lin Liang studies public health at National Yang Ming Chiao Tung University in Taipei. She collaborated on the study with Chen-Te Hsu of the National Taiwan Sport University.
“If only one of the seven tests were available, we would choose the 2.5-meter step-up test,” Liang said. The results were obtained as part of Taiwan’s National Physical Fitness Program, which subjects older adults to the same seven tasks at testing stations across the country.
Liang’s team compared data from 13,423 people aged 65 and over with data from Taiwan’s national health insurance system and then tracked deaths through the end of 2022. On average, 1,631 people in this group died over seven years.
The seven tasks cover four types of physical fitness. A two-minute walk in place measures cardiovascular and pulmonary endurance. A 30-second dumbbell curl and standing up from a chair measure strength.
Two tests assess flexibility: placing one arm over your shoulder and raising the other up your back to check if your fingertips touch. Two tests measure balance and agility: standing on one foot with eyes open and walking 2.44 meters around a cone.
The weights were 2.27 kilograms for women and 3.63 kilograms for men, roughly equivalent to the weight of a gallon of milk. All scores were also included in one overall index.
For each task, the team divided people into five equal groups, from worst to best. They then compared the extremes, adjusting for age, gender, income, education, region of residence, ten diagnosed medical conditions, and self-reported physical activity.
The largest differences between the slowest and fastest fifth groups were observed on the 8-foot distance. In the slowest fifth group, 661 of 2,621 people died, or about one in four. In the fastest fifth group, 133 of 2,701 people died, or about one in 20.
After these adjustments, the risk of death for the top-fifth of participants was 41%, while for the top-fifth, it was 51%. The single-leg standing test was next at 50%, the chair-rising test at 55%, and the two-minute step test at 58%.
The arm-weight-bearing test scored 63%, and the seated reaching test at 79%. Combined, all seven tests outperformed all other tests, reaching 39%.
“Balance is not the result of any single physiological system,” Liang said.
Standing on one leg involves vision and leg strength. It also involves the sensation of head tilt, perceived by the inner ear, and the body’s own sense of limb position. The brain coordinates all of these processes.
Therefore, a low score on one short task may reflect problems in several of these systems at once, before anything goes wrong in everyday life. Other researchers have linked age-related slowing of walking to a similar change.
Falls are another likely explanation. Leg weakness, poor coordination, and slowness increase the likelihood of falls and hip fractures, which can result in hospitalization and sometimes death in older adults. Liang said her team did not directly test this relationship.
Among men, balance and agility ranked highest. Among women, leg strength and balance were about equally strong.
Two people of the same age, both with high blood pressure and diabetes, can differ significantly in their physical abilities. These differences persisted even after the team accounted for preexisting medical conditions.
Only 4,399 of them, about a third, reported engaging in the recommended 150 minutes of moderate physical activity per week. Their reports did not explain what exactly they were able to do.
“Our results suggest that objectively measured fitness reflects an aspect of health that is not fully captured by disease measures or self-reported activity,” Liang said.
In 2016, the American Heart Association argued that heart and lung health should be considered alongside blood pressure.
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