It’s not just the number of hours you sleep that matters, but also when you fall asleep.
Bedtime plays a determining role in the quality of sleep. Going to bed too late leads to sleep deprivation, and as Dr Laurence Plumey, nutritionist, reminds us, “All sleep lost cannot be made up for”. Chronic sleep deprivation is associated with increased risk of cardiovascular disease, diabetes, mood disorders and cognitive deficits. Clearly, neglecting your sleep weakens the entire body. What if two precise hours of the night concentrated most of the physical and mental recovery? According to the specialist, missing this biological window can have a lasting impact on your health.
Over the course of a night, the body goes through several phases: falling asleep, which represents 5 to 10% of sleep time, light slow-wave sleep, which makes up almost half of it, then deep slow-wave sleep (10 to 20%), during which the brain gradually becomes insensitive to external stimulation, and finally paradoxical sleep (around 20%), which is maximal at the end of the night. It is deep slow-wave sleep that is most restorative for the body: its absence makes the following days much more difficult to live through.
The body’s repair during sleep is based on a precise biological mechanism: the secretion of melatonin, the famous sleep hormone. As Dr. Plumey explains, “Melatonin starts to rise in your brain from 11 p.m.”. You should ideally be asleep beforehand to recover as much as possible. The window for restorative sleep is then between 11 p.m. and 1 a.m. It is precisely during these two hours that melatonin reaches its peak, plunging the body into a “very restorative deep sleep”. Far from being at rest, the brain then works intensely: “it stores in memory, it communicates with other organs, it detoxifies its neurons, it produces antioxidants, it regulates hormones”continues the expert in a video.
Going to bed after 1 a.m. means missing the time when the brain recharges its batteries most effectively. And the consequences accumulate: by falling asleep at 1 a.m. and waking up at 7 a.m., for example, you only get a total of six hours of sleep, whereas “Our brain needs on average 7 to 8 hours of sleep to do everything it needs to do”. This deficit promotes an increased attraction to sugary foods, a reduction in physical activity and, ultimately, insidious weight gain.
To optimize your sleep, the National Institute of Sleep and Vigilance (INSV) recommends maintaining regular getting up and going to bed times, including weekends, and going to bed at the first signs of sleep: yawning, heavy eyelids, itchy eyes. In the evening, it is better to focus on a calm activity, disconnect from screens one to two hours before sleeping and avoid exciting things after 2 p.m. One last piece of advice from Dr Plumey which sums it all up: “Sleep, sleep, sleep!”
