Morning gym-goers ‘burn more calories’ during their workouts, according to new study

Good news for early risers who like to do their workouts at the start of their day: a new study has found that morning gym-goers may burn more calories than those who do their exercise routine in the evening.

Researchers came to this conclusion by carrying out a study on mice. They discovered that they have a higher metabolism if they exercise early in the day - and the experts believe that can also be the case in humans.

Scientists in Sweden conducted their study by setting mice on two high intensity workouts at different times in the day and then recorded their adipose tissue, otherwise known as body fat, afterwards. They found that biological processes in the body worked differently depending on the time of day due to each cell’s circadian rhythm, which are physical, mental, and behavioural changes that follow a 24-hour cycle.

Joined by a team from University of Copenhagen, Denmark, the researchers marked an early active phase and early rest phase, corresponding to a late morning and late evening gym session in humans.

They looked at which genes were active in adipose tissue in the mice in each time slot, and discovered those involved with boosting the metabolism were present in larger amounts in the morning slot - regardless of how much food the mice ate. This was because morning workout genes broke down fat by producing heat and mitochondria in the adipose tissue.

Professor Juleen Zierath, of Karolinska Institutet, said: “Our results suggest that late morning exercise could be more effective than late evening exercise in terms of boosting the metabolism and the burning of fat, and if this is the case, they could prove of value to people who are overweight. The right timing seems to be important to the body’s energy balance and to improving the health benefits of exercise, but more studies are needed to draw any reliable conclusions about the relevance of our findings to humans."

It does seem, however, that more research may need to be done. This is because although mice have a long-established model for human physiology and metabolism the researchers say that their comparison, which has been published in the Proceedings of the National Academy of Sciences, is limited by the fact mice are nocturnal.