Why is it so hard to wake up on winter mornings?

 

We need to sleep the same hours in both summer and winter, but the cold and darkness favor sleep. If you haven’t slept well or enough, getting out of bed is more difficult

 

If fruit flies had little alarm clocks that went off when they had to get up for work every day, they would feel the same way in the winter that humans do when it happens to them: their tiny sheets would stick to them. But, because they are not tied to the tyranny of an alarm, when it is cold and dark, they simply wake up later.

In the dark and cold months, with the alarm clock set at the same time as in summer, it is easy to wonder when it rings if we shouldn’t do like the sun, fruit flies, and other animals that also sleep more in winter and set the alarm for later

All had different sleep disorders, were in an urban environment, and did not set an alarm clock. Throughout the year the study concluded that, although the participants slept more in winter, it was not a very significant amount of extra time. What was noticeable was a change in the architecture of sleep, or the distribution of the time we spend in sleeping phases. In winter, participants spent more time in the REM phase. If these results were also obtained when studying people without sleep disorders, the study indicates, it would be the “first evidence on the need to adjust sleep habits to the seasons.”

The environment that promotes sleep is mainly influenced by light, which helps us synchronize with the circadian cycle. “When there is no sun, the body encourages the production of melatonin, the sleep hormone in humans,” says Martínez Madrid. If the alarm clock rings before dawn, or the room is completely dark, waking up is more difficult.

We usually have lower levels of vitamin D, which also has an influence, adds Noelia Ruiz Herrera, professor of Psychology at the International University of La Rioja (Spain), and currently on placement as a researcher with the Division of Sleep and Circadian Rhythm Disorders at Brigham and Women’s Hospital at Harvard Medical School. “Lower levels of vitamin D, which are associated with less exposure to light, can also affect the production of serotonin, which is a hormone that influences our sleep and wake cycle, and our mood,” she explains. Seasonal affective disorder, feeling melancholic and even depressed in these months, can also make it difficult to get out of bed. “When is it worrying? When it influences our daily lives,” says Ruiz.

Changes in habits can also influence sleep. For example, if we do less physical exercise in winter, we will sleep worse, the expert warns, which will make it more difficult for us to get out of bed when the alarm goes off.