Monday , September 26 2022

The time of day affects the calories we burn


The magazine Current Biology This week he is publishing a study showing that energy expenditure depends not only on diet, exercise, and the number of hours we sleep, but also Biological clock.

According to the study, led by researchers at Brigham and Women's Hospital in Boston, the remaining metabolic rate, which is between 60% and 70% Energy expenditure Daily in most adults sitting, varies accordingly The circadian rhythm.

"It's not just what we eat, but when we eat and rest that affects the energy we burn or store as fat," Duffy says.

This way, at rest, our body burns up 10% more calories at the end of the afternoon That first thing in the morning when Metabolic rate It's less.

Habit determinations

"It's not just what we eat, but when we eat and rest that affects energy That we burn or that we keep in our body grease"Says researcher Jane Duffy, co-author of the study," The habitual habit of eating or sleeping is very important for health. "

For researchers, the fact that The circadian rhythm Affect metabolism This is relevant because it can explain why people with irregular sleep schedules are likely to gain weight.

Although energy expenditure has been measured during the day in previous studies, the uniqueness of this study is that the marine rhythm has been analyzed in isolation for the influence of other variables – such as food intake, exercise, or dream – in metabolism.

For this purpose, the experts examined, for three weeks, seven patients Special laboratory Where there were no clocks, no windows, no telephones, no internet. In this way, participants could not know what time it was abroad and could not be guided by their biological clock Environmental factors.

In addition, participants spent hours to go to bed and wake up that changed all the time. Specifically, schedules were delayed four hours each night, the equivalent of traveling west each day through four time zones.

"To be able to measure all circadian cycles throughout the 24 hours of the day, with the same period of twelve hours of Rest and rest Among them, we had to manipulate the relationship between the dream and the biological clock. The two usually have the same rate for each other, so it's impossible to make the resting metabolic rate measurements under the same conditions at different times of day, "says SINC.

Internal clock

"When they do the equivalent of the Earth each week, the internal clock of their body can not keep up, and it was swinging at their own pace," says Duffy. "It allowed us to measure the metabolic rate at different biological times of the day."

The experts examined seven patients in a special laboratory that had no clocks, no windows, no telephones, no Internet

According to the results, the moment of expenditure of low energy corresponds to circadian phase ~ 0 °, where for our body is early in the morning, because there is a drop in temperature in the stomach. On the contrary, the body burns more calories in the 180 ° phase, which occurs about 12 hours later, which will biologically be The end of the afternoon.

They also found that patients' breathing, which is used to measure metabolic rate because it reflects the macroeconomic expenditure, also changes with the 24-hour stages. This indicator was lower at the end of the afternoon and higher on the biological morning.

According to experts, the next line of research will focus on how Appetite And the body reacts to different types of food by the time of day. They also look at how timing, duration of sleep and regular sleep affect body responses.

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