Doctors advise being in light longer during day for better sleep

In winter, some people have trouble sleeping because they do not spend enough time in the daylight, this conclusion was made by scientists at the University of Washington.

The study was conducted on 507 students at the same university. The data showed that students got about the same amount of sleep each night regardless of the time of year. But on school days in winter, students went to bed an average of 35 minutes later and woke up 27 minutes later than on summer school days. This finding surprised the team because Seattle is located at high latitudes and gets about 16 hours of sunlight on a summer solstice day, with enough evening light for social life, and just over eight hours of sunlight on a winter solstice day. That is, evening activity in the summertime with sunlight intuitively seemed to make more sense.

It turned out to be because of the body's internal clock - circadian rhythms. Light during the day - especially in the morning - speeds up your clock, so you get tired earlier in the evening, but exposure to light in the late afternoon or early night delays your clock, delaying the onset of fatigue. Ultimately, falling asleep time is the result of a collision between these opposite effects of light exposure at different times of day, the scientists explained. Each hour of daylight "pushed" the clock forward by 30 minutes, while evening light pushed the clock back by 15 minutes. Thus, because students did not get enough daylight during the winter, their circadian clocks lagged behind compared to summer.

In this regard, scientists recommend going outside during the winter more often during the day, because this effect occurs mostly with natural light - even in cloudy weather.

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