Australasian Science: Australia's authority on science since 1938

Exercise Boosts Cellular Metabolism

By Stephen Luntz

Interaction between exercise and temperature on cellular metabolism.

Moderate exercise burns off more calories than the energy used by the exercise itself, a new study suggests. Without exercise we may burn off less energy in the process of thermoregulation.

A/Prof Frank Seebacher and doctoral student Elsa Glanville of the University of Sydney’s School of Biological Sciences studied the metabolism of native bush rats (Rattus fuscipes). When the temperature is below 30°C the rats use energy to keep their bodies warm.

“Rats that had exercised for half an hour a day did show a metabolic response to cold, and burnt more energy as expected,” says Seebacher. “But in rats that did not exercise, lowering the air temperature even down to a chilly 12°C did not stimulate their metabolism and energy consumption at all.” Despite this, the sedentary rats were able to regulate their body temperature enough to avoid hypothermia.

This is the first study of its kind to show an interaction between exercise and temperature on cellular metabolism.

Seebacher says that bush rats were chosen because “laboratory rats have been bred for characteristics like lack of aggression, which may correlate with metabolism,” and he wanted a cleaner sample.

When put in a cage and fed, the bush rats prefer to spend all their time in a shelter unless they are placed on an exercise wheel to keep them fit. The rats that were part of an exercise program did only 30 minutes of moderate exercise – equivalent to a regular daily walk rather than an athlete in training.

Seebacher acknowledges that the results may not be transferable to humans, but points out that rodents have proved to be good models for many other metabolism studies. “To take advantage of the metabolic boost we receive at temperatures below 30°C, we need to do some light exercise every day. In other words, you don’t need to take exercise seriously, just regularly,” he says.