If you give the mouse a wheel, it will run.
But it may not burn too much extra calories. An interesting new study studies the behavior and metabolism of exercised mice and finds that the behavior of mice does not change when they are not on the runner.
The study, published in Diabetes, is about animals, but it may also be a warning to those who want to start exercising with weight loss.
In recent years, one study after another has focused on the exercise and weight loss of humans and animals. They concluded that exercise itself is not an effective way to lose weight.
In most of these experiments, the weight lost by the participants was numerically much lower than expected, given the large amount of extra calories burned during exercise.
Scientists involved in these studies suspect—and sometimes prove—of both humans and animals that tend to become hungier after exercise and consume more calories. Outside of exercise, they may become more like sedentary. These changes, alone or in combination, may compensate for the extra calories burned during exercise. This means that, in general, energy consumption has not changed and the weight of humans or rodents remains the same.
But to prove this possibility is daunting. This is partly because the movements of people or animals and the changes in these movements after exercise are difficult to quantify. For example, mice can jump, rush, stun, comb, eat, stroll, defecate, or walk around intermittently.
But recently, researchers who target animals have come up with a way to track the movement of animals in cages at any time with an infrared beam. Complex software can then use this information to map out the physical activity patterns of the day, showing when an animal is, when, where, where, how long, or how long it has spent in other ways.
Scientists at Vanderbilt University and other institutions are interested in this, and they believe that this technique is very suitable for tracking the situation before and after exercise in mice, especially when used in specialized metabolic chamber cages— - This cage can quantify the energy consumed by one of the animals that inhabit one day.
Therefore, the scientists set up cages and installed locked running wheels to allow young, healthy, normal-weight male mice to walk freely in cages for four days, providing researchers with metabolism and natural walks for each mouse. Basic data.
Then, the wheels were unlocked for 9 days, and the mice were free to play on the wheels, and they could eat as they please and move around the wheels.
The mice seem to like to jump on the wheels or jump up and down the wheels for hours.
According to the metabolic data, their daily energy consumption has increased sharply, which is reasonable because their exercise volume has increased.
But their eating habits have not changed. Although they burn more calories, they don't eat more food.
However, the way they do things has changed. Almost as they start running on wheels, they no longer wander in cages as they are locked.
In particular, they stopped the long walks that were common before running. Instead, they now usually jog on the wheels for a few minutes, jump down, take a break or take a short walk for a while, then climb back to the wheel, run, rest, take a short walk, and so on.
Daniel Lark, a molecular physiology researcher at Vanderbilt University School of Medicine, who heads the new study, said their changes in timing almost offset the extra calories burned by running.
In general, running mice exhibit a slight negative balance of energy, that is, they burn more calories a day than they consume through eating.
But metabolic data shows that if they don't reduce walking in the cage, the calorie deficit will increase by about 45%.
The reasons for the lack of walking in mice that are running are uncertain.
"They don't seem to show fatigue, nor do they have no time," Dr. Lack said.
He pointed out that for mice, running on wheels is effortless and does not cover all the time they are awake.
He said that the body and brain of the mouse are likely to realize that there will be an energy deficit after starting to run, so a biological signal is sent, suggesting that the animal slows down, saves energy, maintains the internal environment balance, and does not cause weight loss. .
He and his colleagues wanted to explore how rodents' bodies physically perceive changes in energy balance and when to start eating more in future experiments. They also want to study female, old and obese animals.
Dr. Lack said that, of course, mice are never the same as humans, so we are not sure whether the results of this and subsequent trials can be directly applied to humans.
But the results of these studies show that if we want to lose excess weight through exercise, we should pay attention to our diet, and do not increase exercise while reducing other physical activities.