The toll that aging takes on our bodies extends to the cellular level. But the damage accrued by cells in older muscles is especially worrisome, because cells do not regenerate easily and, over time, their mitochondria, which produce energy, decrease in strength and number. But here’s some good news! A study published recently in Cell Metabolism suggests that certain types of workouts may mitigate the toll that aging has taken on our mitochondria. Researchers at the Mayo Clinic recently conducted an experiment on the cells of 72 healthy but sedentary men and women who were younger than 30 or older than 64. The subjects were randomly assigned to one of the following groups:

1) vigorous weight training several times a week
2) brief interval training 3 times a week on a stationary bike
3) riding a stationary bike at a moderate pace for 30 minutes a few times a week and light resistance training on other days
4) no exercise.

The subjects who did the interval workouts showed increases in the number and health of their mitochondria. This was especially the case with the older subjects. It seems as if the decline in the cellular health of muscles associated with aging was “corrected” with exercise, especially if it was intense, says Dr. Sreekumaran Nair, an endocrinologist at the Mayo Clinic and the study’s senior author. In fact, older people’s cells responded in some ways more robustly to intense exercise than the cells of the young did — suggesting, he says, that it is never too late to benefit from exercise.