The sleep onset latency (SOL), which is referred to as the amount of time taken by a person to go from fully awake to being asleep, depends on several things and the most common of all is how tired are you. If you are feeling extremely exhausted you might fall asleep fast but if it was a relaxing day for you then it might take some time to doze off. This is another reason why you fall asleep fast on weekdays and find it difficult to get some shut-eye on the weekend. But this is not the case always, sometimes you might be extremely exhausted and still keep on twisting and turning on the bed this happens due to insomnia and other issues.
People who fall asleep quickly don’t exactly remember what happened minutes before they fall asleep and they might not even be able to recall it at all. This is known as mesograde amnesia. As per some researchers, mesograde amnesia is a result of sleep spindles or bursts of activity in your brain’s hippocampus during the transitioning from wakefulness to sleep.
What else does it mean
Falling asleep instantly does not always mean there is something wrong with you. It is even a sign of sleep deprivation.
In general, it takes 15-20 minutes for a person to go into a deep sleep after going to bed. If it takes more than this time you are probably suffering from insomnia.
If you are sleeping for 6 hours and fall asleep at a lightning-fast speed at night that means your body is craving for more sleep. Not only at night, if your habit of quick sleeping extends to the daytime then it can be a sign of sleep apnoea and narcolepsy. This can also be due to depression.
The bottom line
It is not always necessary that if you fall asleep quickly then have some health issues. But if you are worried or are sleep deprived, then get some more sleep and see if you notice any change. In case you have other issues like daytime sleepiness, snoring then consult your doctor.