Today is December 21, 2016, a day that marks our entry into winter and the day of the solstice. It is therefore the shortest day of the year and therefore also the longest night. But does this little extra at night help us sleep better?
According to experts, we tend to sleep a little longer in winter than in summer in general. But those extra minutes of night during the winter solstice alone wouldn’t be enough to make a noticeable difference in our sleep patterns compared to the nights before and after the solstice.
» I would say yes, day length changes [tout au long de l’année] influence sleep says Brant Hasler, sleep expert and professor of psychiatry at the University of Pittsburgh, USA. » Probably not enough to notice a day-to-day difference between the day of the winter solstice and the days before and after it, but definitely in comparison to the summer solstice “, he adds.
More specifically, the number of hours of day and night people experience depends of course on where they live. In mid-latitudes, we average around 9 hours of daylight around the winter solstice and 15 hours of daylight around the summer solstice.
Previous studies have shown that reducing the number of daylight hours in winter has an impact on sleep. In a 2007 study, for example, researchers analyzed sleep data from about 55,000 people living in Europe and found that they slept about 20 minutes longer on average in winter than in summer. » Many people report being more tired in winter and wanting to sleep more Brant Hasler told Live Science. He then clarified that the changes in habits are mainly due to the reduction in the number of daylight hours which affects people’s circadian clock.
According to the National Sleep Foundation, our circadian clock is controlled by an area of the brain that responds day and night. For example, daylight pushes that part of the brain called the suprachiasmatic nucleus send signals that result in the production of hormones and other physiological changes that keep us awake. In addition, daylight prevents the release of melatonin, a sleep-related hormone.