Sunday , April 11 2021

Time of day affects the calories we burn



The magazine Biology at this time This week published a study showing that energy expenditure depends not only on diet, exercise and the number of hours of sleep, but also on biological clock.

According to the study, led by researchers from Brigham and Women 's Hospital in Boston, the metabolic rate is resting, which is between 60% and 70% of energy expenditure every day in most adult adults, varies according to circadian rhythm.

"This is not only what we eat, but when we eat and rest that has an impact on the energy we burn or store it as fat," Duffy said.

In this way, at rest, our body burns up to a 10% more calories at the end of the afternoon first thing in the morning when metabolic rate That's lacking.

Habit regularity

"It's not only what we eat, but when we eat and rest it impacts energy which we burn or which we store in our bodies as fat"Says researcher Jeanne Duffy, co-author of this study." Regularity in habits such as eating or sleeping is very important for health. "

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

Although energy expenditure has been measured throughout the day in previous studies, the specificity of this study is that circadian rhythms are analyzed separately for the influence of other variables – such as food intake, physical activity. or dream-in metabolism.

For this, specialists were examined, for three weeks, seven patients inside special laboratory where there is no clock, or window, or telephone, or internet. In this way, participants cannot know what time it is abroad and their biological clock cannot be guided environmental factor.

In addition, the participants have assigned hours to go to sleep and wake up which are constantly changing. In particular, the schedule was delayed by four hours each night, equivalent to traveling west every day through four time zones.

"To be able to measure all the different circadian cycles 24 hours a day, with the same twelve hour period rest and rest among them, we must manipulate the relationship between dreams and biological clocks. Usually both of them follow the same rhythm in relation to others, so it is not possible to make measurements of resting metabolic rates in the same conditions at different times of the day, "the researcher told SINC.

Internal clock

"When they do the same thing by circling the earth every week, their body's internal clocks cannot follow, and it oscillates at their own pace," said Duffy. "This allows us to measure metabolic rates at different biological clocks that day."

Specialists examine seven patients in specialized laboratories where there are no clocks, or windows, or telephones, or the internet

According to the results, the lower energy expenditure moment corresponds to the Circadian phase ~ 0 °, where for our body is the morning because there is a decrease in temperature in the stomach. Conversely, the body burns more calories in the ~ 180º phase, which lasts about 12 hours later, which will biologically become late afternoon.

They also found that the patient's respiratory respiration, which functions to measure metabolic rate because it reflects macronutrient expenditure, also varies with the circadian phase. This size is lower at the end of the afternoon and higher on biological mornings.

According to experts, the next line of study will focus on how appetite and the body responds to various types of food according to the time of day. They also examined how the time, duration and regularity of sleep affect the body's response.


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