While some people struggle with falling asleep, others can easily doze off, sleep quickly, or sleep anytime and anywhere. Though it may seem strange, falling asleep too quickly can be a warning sign of a sleep disorder.
1. How does sleepiness occur?
Typically, the feeling of sleepiness arises when a substance called Adenosine accumulates in the brain. When the body is awake, energy depletion and metabolism occur, gradually increasing the amount of Adenosine. The longer the brain remains alert, the easier it is to feel sleepy.
Falling asleep too quickly usually occurs in two situations:
- During the day, fatigue from work makes it easier to fall asleep to recover energy lost in the morning.
- Using sleeping pills or substances that help induce sleep. This is referred to as non-natural sleep.
During sleep, the body gradually reduces the amount of this substance through detoxification by the lymphatic system. Therefore, when waking up in the morning, the level of Adenosine, as well as the feeling of sleepiness, will be at its lowest, keeping us in the most alert state of the day.
For example, if you keep your body awake continuously for 30 hours, your body will run out of energy and you will feel very sleepy, fall asleep quickly, and sleep longer than usual. This is due to the increased levels of Adenosine affecting your nervous system. Similarly, if you stay up late, beyond your normal bedtime, you will quickly feel sleepy due to the increased levels of Adenosine. So, what will happen if the levels of Adenosine are always excessively high?
2. Causes of Quick Sleep
A common reason people quickly fall asleep is due to lack of sleep. If the body does not get enough sleep, rest to recharge energy and eliminate Adenosine, you will quickly feel sleepy.
On average, a person spends more than 8 hours a day sleeping. However, some people may need more or less sleep. If you always feel sleepy, fall asleep too quickly, need many short naps, or often doze off or sleep excessively, it may indicate that your body is severely sleep-deprived.
Poor sleep quality, shallow sleep, and insufficient sleep will also cause you to crave sleep frequently. One of the causes of intermittent sleeping issues is sleep apnea, loud snoring, and breathing disorders that cause you to frequently wake up during the night.
Additionally, teeth grinding or nocturia also leads to a decrease in sleep quality. Periodic leg movements at night may also be a sign of restless legs syndrome, disrupting sleep.
The condition of restless and interrupted sleep is also related to narcolepsy, which is a rare neurological disorder. In this disorder, the brain cannot regulate sleep and wakefulness normally, and the patient will suddenly fall into sleep (sleeping too quickly) without prior warning. If tests do not provide a conclusion or find the cause, it is generally diagnosed as idiopathic hypersomnia.
3. Methods for assessing sleep
The quickest way to determine the level of sleepiness is to perform the Epworth Sleepiness Scale. If the score exceeds 10, there will be a tendency to increase sleepiness.
Another method is to record the sleep onset latency (Multiple Sleep Latency Test (MSLT)) to assess sleepiness and the likelihood of having narcolepsy.
The MSLT test will include 5 short sleep periods, each lasting 20 minutes, spaced every 2 hours over a day.
The MSLT result is considered abnormal if you take less than 8 minutes to fall asleep or enter the rapid eye movement (REM) phase during at least 2 short sleep periods, indicating a high likelihood of having narcolepsy.
Difficulty sleeping or falling asleep too quickly adversely affects long-term health. For quality sleep, you should adjust your lifestyle so that it takes between 5 to 15 minutes to fall asleep, which is the ideal time frame. If you fall asleep too quickly, have short sleep periods, and frequently feel tired or exhausted, you need to consult a sleep specialist for better advice.
