The older we get, the fewer sleep cycles we need to feel rested…
“I missed the sleep train.“This popular expression, which you may be familiar with, is used to refer to missing the ideal moment to fall asleep. It is a perfect representation of sleep cycles diagrammed in the form of a train.
A night is made up of a succession of several “trains” or “sleep cycles”. Each cycle itself is made up of 4 phases: falling asleep, slow sleep (light/deep), REM sleep and then the waking phase. In the first half of the night, the share of deep sleep is higher (we sleep more deeply at the beginning of the night) while in the second half of the night, the share of light and paradoxical sleep is more abundant.
How many cycles of sleep do you need each night to feel refreshed when you wake up? A sleep cycle lasts between 1 and 2 hours depending on the individual.A good night’s sleep is at least 3 to 5 cycles of 90 minutes on average.” report the Inserm doctors. We should therefore sleep between 4.5 and 7.5 hours of sleep per night to be well when we wake up. This may not seem like much, but these are averages.
Besides, we are not all equal in terms of sleep. Some of us need a lot of sleep, others less.The amount and quality of sleep needed varies greatly from person to person. Environment, hygiene and lifestyle play a role in the ability to sleep and recover well during a night’s sleep. But whatever the amount of sleep needed by each person, that of deep sleep (the one who repairs the most) would be relatively constant, while the durations of light sleep and REM sleep (less restorative) would vary” they justify.
In other words, a person can sleep 3 sleep cycles and feel good as long as their cycles are mostly composed of deep sleep. Another can sleep 5 or 6 cycles and feel tired if they are mostly composed of REM sleep, in which the body does not recover enough. Also, sleep cycles vary with age. We tend to need fewer sleep cycles as we get older, explained Dr. Marc Rey, neurologist and President of the National Institute of Sleep and Vigilance (INSV), during a previous interview. Thus, 3 or 4 sleep cycles can be enough after the age of 60, while a 25-year-old person needs 5 or 6 cycles to recover well.
To avoid “missing the sleep train”, the ideal is to listen to your body which is starting a sleep cycle and to go to bed at the first signs of fatigue (itchy eyes, heavy eyelids, yawning). If we don’t do this, it’s like being at the train station, we’ll have to wait a little while before getting on the next train. If we transpose the analogy to sleep: we risk having to wait a whole cycle (so about 90 minutes) before feeling the urge to sleep again. It is also recommended to follow a sleep routine (even on weekends) by trying to go to bed at the same time every day.
