If you're a top athlete over 35, your performance tends to drop by about half a percent each year — and this slow decline might be due to how our bodies naturally age, no matter the sport.

When top athletes get older, their performance drops at about the same rate in running, rowing, and swimming — which suggests their body systems all slow down together, not one faster than the rest.

After age 35, people get slightly worse at endurance sports each year—and that slowdown matches how much their lung and heart fitness drops. This suggests that losing aerobic fitness might be a big reason why endurance fades with age.