You may want to reorganise your workout schedule because a study says people burn 10 percent more calories in the late afternoon and early evening than early morning.
The researchers set out to determine how circadian rhythms, which control the body’s sleep cycles, influence calorie burning.
They studied seven people in a special laboratory where they were insulated from the time outside. Clocks, windows, phones, and internet were not available in the laboratory.
The study participants were assigned times to go to bed and wake up. Each night, those times were adjusted four hours later, the equivalent of travelling westward across four time zones each day for three weeks.
The researchers found that people’s body temperatures were lowest late at night and early in the morning and that their highest was in the late afternoon. They learned that the higher the temperature, the more calories burned.
“The fact that doing the same thing at one time of day burned so many more calories than doing the same thing at a different time of day surprised us,” says Kirsi-Marja Zitting, lead author of the paper.
Co-author Jeanne Duffy said: “Because they were doing the equivalent of circling the globe every week, their body’s internal clock could not keep up, and so it oscillated at its own pace.
“This allowed us to measure metabolic rate at all different biological times of day.
“It is not only what we eat, but when we eat — and rest — that impacts how much energy we burn or store as fat.
“Regularity of habits such as eating and sleeping is very important to overall health.”
The research was published in Current Biology