Autophagy and Exercise

SYNOPSIS: “Worth All the Sweat” (Economist, Jan. 2012); “Exercise as Housecleaning for the Body” (NYT); "Exercise as Housecleaning for the Body," Gretchen Reynolds, NYT, Feb. 2, 2012)

We’ve all heard about the many downsides of being under pressure, but did you know that when it comes to the health of your cells, stress can be a good thing?

Autophagy is the process by which cells clean out the “garbage” that accumulates in them. Cells constantly recycle old proteins and internal dead parts to use for energy. When the body undergoes stress—food deprivation or physical exertion—autophagy kicks in. This mechanism could help animals and humans survive through leaner times when sustenance is not readily available.

Researchers have known for a while about the anti-aging effects of cell recycling. When animals are fed a near-starvation diet, they live longer. Some intrepid humans have adopted this practice with the hope of prolonging their lives. Recent research shows, however, that strenuous exercise may be a less radical lifestyle change that gets similar results.

In the journal Nature earlier this year, Dr. Beth Levine and colleagues (UT Southwestern Medical Center) tested the hypothesis that one of the benefits of exercise is autophagy.

In the first group of mice, her team tagged autophagosomes (the structures that form around the cell parts designated for recycling) green to be visible. As the rodents ran on the treadmill, the number of autophagosomes in their muscle tissue increased.

In the second group of mice, scientists deactivated the mice’s ability to self-clean their cells. Even exercise did not stimulate the process. The mice could not run as long and their bodies’ ability to use sugar from the bloodstream was highly compromised. In other words, it became highly difficult for their cells to produce the energy they needed.

Insights into how autophagy works could help researchers treat type 2 diabetes more effectively.

Moreover, other recent studies suggest that diseases like cancer, dementia, Alzheimer’s, and muscular dystrophy are more likely to develop if autophagy is inhibited. These findings may explain why some researchers have found evidence linking enhanced cognitive abilities to moderate exercise.

So, whether you run on a treadmill like the mice or scull on the Schuylkill, get out there and scrub your cells! Or, if you prefer an even more simplistic dictum, eat less and exercise more.