To be cheerful, to feel rested and full of energy – what factors influence this?
The question seems elementary from a scientific point of view, but it is extremely important, because it is the inability to concentrate and the loss of vigilance that often cause traffic accidents and accidents at work.
The same lack of sleep, which leads to daytime fatigue, reduced productivity or missing work, is estimated to cost developed countries about two percent of their gross domestic product annually.
For example, for the United States of America, losses amount to approximately $411 billion.
Despite the long list of effects that fatigue can have, the factors that influence whether we’re awake and alert during the day are poorly understood.
It is to them that a new study by scientists from the University of California at Berkeley and King’s College London is dedicated.
The experiment involved 833 volunteers from the US and the UK, their average age was 46.2 years: some were identical or fraternal twins, while others were unrelated.
Everyone had to eat a few standard breakfast foods that differed in nutritional composition and wear a watch that recorded sleep and physical activity and tracked glucose levels.
The subjects kept diaries in which they noted what they ate, and using a special smartphone application, they assessed their level of vigor on a scale from zero to one hundred after each meal.
On average, everyone fell asleep at 23:25, slept for 7.66 hours, and had breakfast at 08:12. After two weeks of the experiment, the researchers found some patterns.
First, people who slept longer felt more focused and alert the next day. Yes, this is not surprising, but it was not so much the duration of sleep, but the time of awakening: if the participants got up later than usual, they felt more alert.
The time of going to bed had a similar effect: when a person went to bed later than usual and at the same time slept a sufficient number of hours.
Secondly, volunteers were more alert and alert on days when they were physically active the day before, but not at night.
A high-carbohydrate breakfast also helped, although high-protein foods, on the contrary, reduced energy levels.
Scientists note that in 98 percent of cases, participants did not consume caffeine, and its presence did not affect the results.
Thus, the usual coffee for breakfast is not an important predictor of alertness and ability to concentrate.
Finally, glucose levels played a role. It turned out that a lower glycemic load after breakfast helped to stay alert.
In addition, the researchers identified four key factors that were important at the individual level: mood, age, sleep quality, and meal frequency.
“Indeed, participants who ate an average of five meals a day or more had significantly lower levels of alertness than those who ate three to four meals a day,” the study authors concluded.
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