Asking middle-aged and older people to balance on one leg for 10 seconds could be a simple way to predict future life expectancy, research suggests.

In an observational study published in the British Journal of Sports Medicine, not being able to stand on one leg for 10 seconds was linked to a near doubling in the risk of all-cause mortality over the next decade.

Using the Clinimex Exercise cohort study, researchers analysed data from 1,702 participants, most of whom (68%) were men, and were aged 51-75 years at their first check-up.

They were weighed, questioned about their medical history, and asked to stand on a flat platform and complete a 10s one-legged stance (OLS) on either their left or right foot.

While balancing, they were asked to place the front of the free foot on the back of the opposite lower leg, keep their elbows extended, arms naturally placed close to the body, and gaze fixed on an eye-level point at a 2m distance.

Up to three attempts were allowed and a simple criterion was applied – ability to complete 10s OLS on either foot, keeping the correct initial position and without any other support.

Overall, 20.4% of the individuals were unable to complete the test, the study authors said, noting inability increased with age, practically doubling at each 5-year age-group interval from 51-55 years.

During a median follow-up of 7 years, 7.2% of participants died; 4.6% of the people who were able to complete the test and 17.5% of those who were unable to complete.

‘Our data show that middle-aged and older participants unable to complete the 10-s OLS had lower survival over a median of 7 years compared with those able to complete the test, with an 84% higher risk of all-cause mortality, even when other potentially confounding variables such as age, sex, BMI and clinical comorbidities or risk factors … were taken into account,’ the study authors wrote.

There was a potential benefit to including the 10-s OLS as part of routine physical examination in middle-aged and older adults, they concluded.

‘In our 13 years of clinical experience routinely using the 10-s OLS static balance test in adults with a wide age range and diverse clinical conditions, the test has been remarkably safe, well-received by the participants, and importantly, simple to incorporate in our routine practice as it requires less than 1 to 2 min to be applied,’ they said.

Study limitations included lack of data about previous falls, smoking and medication use, the researchers noted, as well as the cohort being primarily composed of white people.

Future research should investigate the biological mechanisms that may explain the observed association, and to test whether modifications to the balance test, such as different arm and foot positions, could contribute to even more powerful survival analysis.