Looking older than your age is a problem that’s more than skin deep. An article published in the British Medical Journal says your perceived age… or how old you are compared to how old people think you look, is a good predictor of overall health.

In a study involving three-hundred-eighty-seven pairs of twins, all older than seventy, participants guessed the ages of the twins, viewing half of a pair of twins on one day and the other half on another day. All the twins were selected from the University of Southern Denmark’s Danish Twin Registry. No mixed-gender twins were included in the study.

The researchers measured the twins’ cognitive and physical abilities and the health of their telomeres [TELL-uh-meers]… small structures within cells that keep DNA intact as cells divide, helping to slow the negative effects of aging. They also kept track of the twins for several years, noting when they died.

The study results showed that the younger-looking twins usually lived longer than their older-looking siblings, and were generally in better health. They also tended to have longer telomeres.

The researchers said perceived age is affected by things like depression, smoking, sun exposure and low socioeconomic status. They also recommended “perceived age” as a good way to gauge a person’s overall health. So if you want to stay looking and feeling as young as you can, wear sunscreen, put down that cigarette and get out for a refreshing walk several times a week. Over time, these small habits could add up to make a big difference.