Science writing, 13 feb. A team of scientists has shown in mice that, depending on the time of day it is done, physical exercise can increase fat metabolism (and burn more or less).
The study, carried out by the Karolinska Institutet (Sweden) and the University of Copenhagen (Denmark), has been published this Monday in the journal Proceedings of the National Academy of Sciences (PNAS).
Research has shown that mice that exercised in an early active phase—equivalent to morning exercise in humans—increased their metabolism more than mice that exercised at a time when they normally rest.
Physical activity at different times of the day can affect the body in different ways, since biological processes depend on the circadian rhythms of cells.
To find out how the time of day exercise affects fat burning, the researchers studied the adipose tissue of mice after a bout of high-intensity exercise performed at two times in the daily cycle, an early active phase and an early active phase. early rest period (corresponding to a session late in the morning and late in the afternoon, respectively, in humans).
They studied various markers of fat metabolism and analyzed which genes were active in adipose tissue after exercise.
Thus, they discovered that physical activity in an early active phase increased the expression of genes involved in the breakdown of adipose tissue, thermogenesis (heat production) and mitochondria of adipose tissue, indicating a higher metabolic rate.
These effects were only seen in mice that exercised in the early active phase and were independent of food intake.
“Our results suggest that late-morning exercise might be more effective than late-afternoon exercise in boosting metabolism and fat burning, and if so, might be useful for people who are overweight.” , says Juleen R. Zierath, from Karolinska.
However, although mice and humans share many basic physiological functions, and mice are a well-established model of human physiology and metabolism, there are also important differences, such as that mice are nocturnal.
“Timing appears to be important for the body’s energy balance and for enhancing the health benefits of exercise, but more studies are needed to draw reliable conclusions about the relevance of our findings to humans,” Zierath argues. EFE
ecg/icn