We cannot repeat it enough: noise is a real nuisance when it comes to sleep. “In the environment, it is even the main cause of impaired sleep” underlines Dr Joëlle Adrien, neurobiologist at Inserm and author of Better sleep and beat insomnia.
First of all, noise can, at bedtime, prevent falling asleep, especially in people who are sensitive to it. But its effects on our sleep are much more pernicious. Because even if we have the impression of being used to it, the consequences on our sleep are always present.
“During the night, the brain continues to perceive signals from the environment, to process and analyze different information. It is therefore doing work that it should not be doing, which disrupts sleep and its restorative properties“ explains the neurobiologist.
Repercussions in the 3 phases of sleep
This brain activity causes a cascade of physiological reactions (secretion of adrenaline, norepinephrine and cortisol, acceleration of the heart rate, increase in blood pressure) which will affect sleep, with different repercussions. according to the phases of sleep.
• During light sleep : the slightest noise can cause either a micro-alarm clock, or a frank awakening. With the risk, if it happens in the early morning, of not being able to fall asleep again.
• In the deep sleep stage (which corresponds to the first part of the night), it takes a lot of noise to wake us up. “It is indeed the moment when the noises are least perceived” confirms the specialist.
A strong noise nuisance can cause a return to light sleep, less restorative.
• In the paradoxical sleep stage (distributed especially in the second part of the night), the sensitivity to the sound environment is more variable.
“Noise, if it does not directly cause you to wake up, modifies the phases of sleep, which change, always going towards a lighter stage” summarizes the specialist. Fragmented and lighter, sleep is ultimately less recovering.
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