How it is calculated

BodyYears estimates your body age from three physical tests and your habits. Here is what we measure, which research we rely on and what the limits are.

What BodyYears estimates

Your body age is the age at which your results would be typical, based on published reference values for women and men of each age. If your results look like those of people younger than you, your body age is lower than your real age. If they look like those of older people, it is higher.

It is not a biological age measured in a lab. It is a wellness estimate that helps you know your starting point and track your progress.

The three tests

Sit down and get up. This test works your mobility, strength, balance and coordination. One study followed more than four thousand adults aged forty-six to seventy-five for about twelve years. A lower score was associated with a higher risk of death.

Stand on one leg. This test measures balance. In adults aged fifty-one to seventy-five, being unable to stand on one leg for ten seconds was associated with a higher risk of death in the following years.

Stand up from a chair or do push-ups. The thirty-second chair stand is a recognized test of leg strength. Reference values have been published by age and sex. Depending on your age the app offers push-ups instead, which measure upper body strength. In active men, a higher number of push-ups was associated with fewer cardiovascular problems.

Your habits

The questionnaire covers your sleep, activity, diet, stress, smoking and alcohol. These habits count in the estimate. They also show you the two that weigh the most and shape your thirty-day plan.

How the camera measures

During the tests, your iPhone spots the key points of your body such as your shoulders, hips, knees and ankles. That is how it counts your reps, times your balance and spots each time a hand or a knee touches the floor. Everything happens on your phone. The images are never recorded or sent. If the camera cannot see well, you can correct your result by hand.

The limits

The studies cited show links between these tests and long-term health. They do not prove that a better score makes you live longer. Your result can also vary with fatigue, the floor, the light or where the phone stands. BodyYears does not diagnose anything and does not replace a health professional.

The calculation in detail

The full formula will be published on this page before the app is released.

Sources

• Araújo CGS et al. Sitting-rising test scores predict natural and cardiovascular causes of deaths in middle-aged and older men and women. European Journal of Preventive Cardiology, 2025.
• Brito LBB et al. Ability to sit and rise from the floor as a predictor of all-cause mortality. European Journal of Preventive Cardiology, 2014.
• Araujo CG et al. Successful 10-second one-legged stance performance predicts survival in middle-aged and older individuals. British Journal of Sports Medicine, 2022.
• Jones CJ, Rikli RE, Beam WC. A 30-s chair-stand test as a measure of lower body strength in community-residing older adults. Research Quarterly for Exercise and Sport, 1999.
• Rikli RE, Jones CJ. Functional fitness normative scores for community-residing older adults, ages 60-94. Journal of Aging and Physical Activity, 1999.
• Yang J et al. Association between push-up exercise capacity and future cardiovascular disease events among active adult men. JAMA Network Open, 2019.