In winter we sleep more and more soundly, or at least we should.
To say it is one study published in the journal Frontiers in Neurosciencewhich found that humans experience longer REM sleep in colder than summer months, even in artificially lit urban areas, and shallower sleep in autumn.
How the research was carried out
The researchers of the Charité Medical University of Berlin who have carried out the research have come to the conclusion that deeper sleep in winter depends on the fact that the human body’s biological clock is regulated by the sun and that the change in the length of the day and exposure to light over the course of the year can affect the length and quality of rest.
The research team recruited 292 people with sleep-related difficultiesto undergo studies called polysomnographies.
Participants were led into a laboratory where they were asked to sleep naturally. While they were doing it was monitored the quality, type and duration of their rest.
The study excluded people on insomnia medications and people who experienced technical problems during polysomnography or a REM sleep latency greater than 120 minutes.
Despite the subjects being in an urban environment with low natural light exposure and high light pollution, the scientists discovered subtle but striking changes over the course of the seasons.
In particular, total sleep time lasted about an hour longer in the winter than in the summer, and the participants experienced 30 minutes more of REM sleep, again during the winter than in the warmer months.
REM sleep is directly linked to the circadian clock, which is affected by changing light.
The team, while acknowledging that the findings need to be validated in a population with no sleep difficulties, said the seasonality changes could be even greater in subjects with undisturbed sleep.
How light affects sleep
Sunrise, day, sunset and evening have different light intensity levels and colors that the body interprets as stimuli to perform or not perform different activities. A bluer light in the morning gives a boost of energy and helps you get out of bed. On the other hand, bright daylight with cooler tones signals to the body that it is time to be alert and productive. Finally, at the end of the day, the amber colors of a sunset prepare you for sleep.
We must also not forget that during the winter the entire solar cycle is condensed and there are more hours of night or darkness. As a result, not only does darkness make you want to sleep more, but shorter hours of daylight limit attention.
The influence of light also changes based on where you live.
If your city is closer to the equator the winters may be slightly brighter than others, so your sleep schedule may not change much compared to the warmer months.
Also there amount of light pollution it can affect the circadian rhythm, as well as the climate.
Il heat in excess and the decrease in humidity in the air contribute to poor quality sleep, since the human body requires a certain degree of cold to sleep better.
Why sleep is important
Circadian rhythms help guide sleep patterns, but they also determine one’s daytime alertness and productivity. If you don’t get enough or not enough sleep, your daily life and general well-being suffer. Mental health, metabolic health, and cardiovascular health are all linked to sleep.
Poor sleep also affects nutritional choices which, in turn, can worsen sleep, setting off an unhealthy vicious cycle.
When sleep is scarce we are more inclined to eat worse and to prefer poor quality foods with few nutrients but these in turn, if consumed frequently, also have an impact on the quality of rest and the desire to sleep more often.
How to sleep better
- Try to go to bed and wake up at the same time every day, even on weekends.
- Create an environment conducive to sleep by making sure your bedroom is cool, dark and quiet.
- Use comfortable bedding and an adequate mattress to best support the body.
- Limit the use of devices before bedtime because the blue light emitted by electronic devices can suppress production of the sleep hormone melatonin, making it more difficult to fall asleep.
- Avoid caffeine and alcohol in the hours close to bedtime.
- Practice relaxation techniques before bed or engage in a pleasant, relaxing activity like a hot bath or reading a book that can help you relax and prepare for sleep.