23 June 2020 | Conseil du bien dormir
Good sleep depends on a variety of parameters: healthy fatigue, a healthy lifestyle, a peaceful mind, suitable bedding and a pleasant outdoor environment. We humans are homeothermic, meaning that our internal temperature must remain relatively stable. When we stray from this temperature, the body reacts through various thermoregulatory mechanisms to restore the essential balance: shivering to warm up and perspirating to cool down.
During the day, our body temperature varies slightly, according to our biological clock in our brains. Throughout the evening, the core temperature drops, telling our body that it is time to go to bed. The greater this drop in temperature, the easier it is to fall asleep. Conversely, in the morning, the body’s core temperature rises telling the body that it must wake up. When the evenings are hot, this cooling feeling is drowned out by the outside temperature, which in turn disturbs and delays falling asleep.
When sleeping, the thermoregulatory mechanisms are also at rest. Hot conditions reactivate these mechanisms resulting in lighter, fragmented sleep, with fewer episodes of deep and REM sleep. Ideally, bedroom temperature should be between 15 and 22°C. Likewise, when one slips under the duvet, heat exchanges occur between our bodies and the bed. A light breathable duvet is the best choice.
When it is hot, the natural reflex is to cool the environment. Conventional measures work, such as ventilating the room in the morning while it is still cool, then closing the window and shutters to create a draft. A fan or an air conditioner could also be used, silent where possible so as not to disturb sleep. This type of device should logically be placed towards the head of the bed, because the head and the upper body are the parts which require most cooling. Finally, there is an age-old trick: to place a bowl of water in the room.
Choose breathable materials such as cotton, which does not stick to the skin unlike polyester for example. For pajamas, choose a loose and light outfit that allows the flow of air between skin and the fabric.
In summer, remember to hydrate yourself regularly because it is a time when we sweat more and we are more likely to become dehydrated. Keep a bottle of water right next to your bed; if you wake up at night this avoids having to get out of bed to drink.
Also, eating lighter meals in the evening is good advice. This applies throughout the year, but even more so to summer evenings. Indeed, after a meal digestion activity increases the body temperature. A light meal helps to slow down body functions. Choose fruit, fish or even white meat. Avoid alcohol because it causes nocturnal awakening.
A final good piece of advice is to take a warm shower just before bedtime. This simple trick moistens the skin, cooling the body quickly and effectively. For the hardiest, finish this shower with very cold water, to stimulate blood flow and cell renewal.
Summer heat certainly affects our form and our activities during the day so let’s limit the disturbance of our nights for better rest!