If people are sufficiently like mice, scientists have discovered another good reason to exercise.
Elaborate studies with laboratory mice seem to prove that exercise cleans junk out of cells and therefore has a renewing effect. OK, you say, I’ve heard that before. That’s what the guy in the park said about Dr. Z’s Magic Elixir — or was it Zillah’s Snake Oil?
No, these were real, white-coated scientists who bred special batches of mice. Made one batch diabetic, with extra fat in their arteries, and then made them run and run.
The running mice got much better. That was because their cells developed enhanced autophagy, a Greek way of saying “self-eating,” which, in this case, meant the cells ate the junk lying around in heaps in their corners, making energy in the process, and felt great. Well, they acted like they felt great. Hard to tell with mice.
Cell scientists have known about self-cleaning cells in mice and men for a long time. What they didn’t know before these experiments was that exercise accelerated and increased the behavior.
“Autophagy affects metabolism and has wide-ranging health-related benefits to the body, and so does exercise,” says Dr. Beth Levine, a Howard Hughes Medical Institute investigator at the University of Texas Southwestern. “There seemed to be a considerable overlap, in fact, between the health-related benefits of exercise and those of autophagy,” but it hadn’t been clear until these elaborate experiments how the two interacted.
What they discovered was after just 30 minutes of running, the mice developed significantly more debris-destroying membranes in their cells, which meant they were cleaning out their cells of waste material at a faster rate.
As a control, they then developed mice which could not increase that capacity and discovered that they tired much more rapidly when running more than normal mice did. Their research led them to speculate that faulty cell-cleaning may contribute to the development of a range of diseases, including diabetes, muscular dystrophy, Alzheimer’s and cancer.
The studies convinced Dr. Levine. “I never worked out consistently before,” she said. Now, having witnessed how exercise helped scour the cells of the running mice, she owns a treadmill.
LIFE SCIENTISTS work with mice rather than human beings for many obvious reasons. The most compelling of these is that the DNA of mice — and all other mammals — is very similar to that of humans. What goes for mice also goes for us to a remarkable extent. That profoundly dazzling fact explains, in part, the reverence for life — for all living things, from chiggers on up to Dr. Beth Levine — that some philosophers develop.
This world we live in is a truly wondrous place.
— Emerson Lynn, jr.
