Exercising in the morning may burn more fat than at other times of the day, new research suggests.
Biological processes work differently depending on the time of day, because of each cell’s circadian rhythm – our body’s natural cycle of changes during each 24-hour period.
A new study by researchers at Sweden’s Karolinska Institute and the University of Copenhagen has shown that mice have a higher fat metabolism when they exercise in an early active phase of their daily cycle than in an early resting phase.
This suggests that people may also see more fat loss if they exercise late in the morning, as opposed to late in the evening, according to the scientists.
“Our results suggest that late morning exercise may be more effective than late evening exercise in terms of boosting metabolism and fat burning, and if this is the case they could be of value to overweight people, said Professor Juleen Zierath, from the Karolinska Institute.
The scientists got mice to exercise intensively at two times of the day and studied the impact on their adipose tissue, also known as body fat.
They looked at which genes were active in fat tissue and found that those involved in boosting metabolism were more present in the morning, regardless of how much food the mice ate.
The researchers found that the earlier period of exercise increased the expression of genes involved in breaking down fat by producing heat and mitochondria, indicating a higher metabolic rate.
“Appropriate timing appears to be important for the body’s energy balance and for improving the health benefits of exercise, but more studies are needed to draw reliable conclusions about the relevance of our findings to humans,” said Prof. Zierath .
Mice are a long-standing model for studying human physiology and metabolism.
However, the researchers say their comparison, published in the Procedures of the National Academy of Sciences magazine, is limited by the fact that mice are nocturnal animals.
Previous studies have suggested that an early morning workout on an empty stomach can help accelerate weight loss and boost energy levels.
Exercising early in the morning, when insulin levels are lower after an overnight fast, is believed to prompt the body to tap into its fat stores for fuel rather than just focusing on recently consumed calories.
Additional reporting by SWNS