Scientists Get Closer to Figuring Out How Exercise Works

But We’ll Have to Wait On the Workout Pill

by Jovaughn Lane, age 14

The study reported a compound that increased the activation of a protein called REV-ERB, which is known to partially control animals’ circadian rhythms and internal biological clocks.

The study was tested on mice. The mice that were injected with the compound lost weight even on a very high fat diet, while also improving their cholesterol profiles. Unexpectedly, the mice that were injected also started to use more oxygen throughout the day, expending five percent more energy than the untreated mice. In most cases, they were more physically lazy and inactive prior to the injection. The drug seemed to provide them with a workout without the effort.

Interested, the Scripps scientists along with researchers from Pasteur Institute in France and other institutions set out to find out what their compound might be doing inside muscles to provide this simulated workout. They knew the drug increased the potency of REV-ERB but did not know what REV-ERB actually does in muscles.

So in a separate part of the experiment, scientists used genetically engineered mice that did not generate very much REV-ERB. They noticed these mice were weak and inefficient specimens, and produced far fewer mitochondria than the normal mice. Mitochondria are the cellular structures that produce energy using up oxygen. But when scientists added the REV-ERB-stimulating compound, they found the genetically modified mice began to make more, and strengthen existing, mitochondria. This is the same effect that exercise has on mitochondria. Under regular conditions, the mitochondria in muscle cells increase in number and strength during exercise. These weak, slow, genetically modified mice had a 60% reduced oxygen capacity compared to regular mice. This is the same effect that exercise has on mitochondria.

Finally, scientists injected sedentary mice, increasing their production of REV-ERB far more than regular mice would be expected to have. When they tested these mice on little treadmills, they ran an exceptionally longer time and distance than untreated mice, even though they had not been training.

Scientists are unsure of the potential harmful side effects the compound could have. Although taking a pill may be the easiest thing, no drug can take place of all the good things exercise can do for us, such as, a psychological feeling that we are improving our own lives. It is doubtful that exercise will be fully reduced to tablet form in the near future.

[Source: New York Times]