The cold and darker winter season affects our sleep behaviour in different ways. Some people struggle to get going and go to bed earlier than usual. Others fall asleep later in winter than in the summer months. A recent study provides clues as to why this is the case. 

Sleep duration hardly differs

Scientists at the University of Washington in Seattle found in a study involving 500 participants that they fell asleep on average 35 minutes later during winter. However, they also woke up almost half an hour later in the morning compared to summer days. Overall, the total amount of sleep across seasons hardly differs. 

Catching daylight

The cause appears to be daylight, of which we receive less in winter—because the sky is often cloudy or overcast. As a result, the body’s internal clock slows down, and sleep begins later at night. Those who want to counteract this effect should expose themselves to more daylight during the day, even when it is overcast outside—for example, by taking a walk at midday when it is brightest outdoors.