Every person is totally unique, which means that no two people sleep exactly alike. Still, sleep scientists have conducted heroic amounts of research on this fascinating and essential bodily function, with the effect that we understand more about how people sleep than ever before.
If you are someone who struggles with sleep, you might be interested to learn why your sleep clock is so much different than everyone else’s. This guide to the body’s sleep cycles might give you much-needed insights into your own patterns and help you find solutions that fit your sleep needs.
How the Body Regulates Sleep
One of the most important questions for sleep scientists to answer is: How does the body know when to sleep? Every vertebrate animal sleeps, but the amount of sleep an animal needs per day is highly variable. For example, koalas require more than 20 hours of sleep per day, but the typical African elephant snoozes for under two hours every night. Research has found that the ideal amount of sleep for people is between six and 10 hours per day, which can be affected by factors like age, occupation, mental state and genetics.
Still, every person has two primary processes for regulating sleep: circadian rhythms and sleep drive. Circadian rhythms are tracked by a biological clock. There are rhythms for eating, for body temperature and, crucially, for sleep. If the circadian rhythm for sleep is disrupted, the body might not know to release crucial hormones that make you feel sleepy and prepare various systems for rest.
The other process is your sleep drive, which is like your body’s hunger for sleep. As the time since your last rest increases, your body’s desire for sleep increases, and when it passes a certain threshold, you will experience an immediate need to sleep. Though your body cannot force you to eat to end hunger, it can force you to sleep; when you are severely sleep deprived, you could pass out anywhere, including during an important meeting or behind the wheel of a car. You might even fall asleep for a few seconds with your eyes open, totally unaware that you are dozing.
Both circadian rhythms and sleep drive can become disrupted and dysfunctional, making it more difficult for you to achieve the rest your body needs when it is appropriate to do so. For example, if you work a night shift, your circadian rhythm may work against you, as a primary way your body maintains its biological clock is by tracking daylight; at nighttime, it gets sleepy. Similarly, if you are in the habit of taking naps in the afternoon, your sleep drive might not be strong enough by bedtime to let you drift off easily. In both cases, you might need to rely on extra strength sleep aids to help you fall and stay asleep.
Patterns of Sleep Cycles
Another key component of feeling rested after a night’s sleep is achieving the right pattern of sleep cycles while you are asleep. Throughout the night, your body shifts between different two types of sleep: non-REM and REM. Non-REM sleep is composed of four stages, as your body moves from awake and falling asleep to deep sleep, and from there, it slowly begins to wake up again by moving through REM sleep, which has brain activity similar to waking. After REM, your body moves back into the non-REM cycle, and the pattern continues, though you should spend less time in deep sleep with every repetition.
At present, sleep researchers still are not certain why the body follows this pattern during healthy slumber, but given that it is seen again and again in good sleepers, it must be critical to the processes the body is completing while the body is at rest. Thus, if your body is not passing through these stages in the same order or for the necessary duration, you might not feel as rested in the morning, and your body might continue to be in need of more sleep throughout the day.
There are almost unlimited reasons why a person might experience disruptions to their sleep, from indigestion to trauma. Fortunately, there are dozens of solutions available to help you regain control over your sleep and achieve the feeling of reinvigoration you deserve after a good night’s sleep.
