Have you ever slept many hours, yet you still feel very tired during the day? Or on the contrary, you sleep very little and wake up with lots of energy? Confusing, right?. This is completely normal, as it is fully dependent on sleep cycles. As the body prepares for sleep and awakening, many factors come into play. The body has different internal clocks, which we call circadian clocks, basically a system for synchronizing your body’s activities with the cycle of the day.
You may think that sleeping is a period of complete rest, but it is not. During the hours of nighttime sleep, many processes prepare our body to be ready for the new day. Muscles are regenerated and hormonal processes take place during this time, so sleep and rest are more than necessary for our body to function properly.
What are circadian cycles?
They are mental, physical and behavioral changes that follow a 24-hour course, natural processes that affect almost everything that has life.
These are synchronized with environmental rhythms, so we tend to rest when it is dark and to be more active when it is light, but they can become misaligned due to various circumstances such as jet lag, artificial light, and even caffeine consumption can alter this process by giving the body false signals of wakefulness.
The central circadian clock is located in the brain and indicates when it is time to go to sleep. The importance of respecting these cycles is because the production of hormones is closely associated with them, such as the growth hormone which has its peaks of secretion during the night, as well as cortisol, and thyroid stimulants that are regulated by circadian cycles.
The cortisol hormone regulates allergies, so it is better to sleep at night to be less likely to suffer from allergies. The thyroid regulates metabolism, so if you sleep during the day instead of at night, you will tend to gain weight more easily and will not use your energy optimally.
Sleep cycles and the need to sleep
Sleep is a biological need that the body has and increases when one has been awake for a long time. A compound called adenosine is related to this need, so while we are awake, the level of adenosine in our brain keeps increasing and the increasing levels will mark a change in sleep.
Sleep cycles are repeated every 90 minutes, however, they can be longer or shorter depending on the person and different conditions.
It is recommended to carry out five of these cycles per day so that the total sleep would be about seven and a half hours. But this does not mean that you should always sleep this amount of time. It is very important the moment in which you wake up if you do not want to feel confused and tired, you will feel much better if you wake up in the REM phase.
Light Sleep – Stage 1 + 2 Sleep
Is the transition between sleep and wakefulness. This is why we can sometimes be aware of what is going on around us in this sleep, an example would be when we fall asleep on the bus lightly and wake up when we arrive at our stop.
Have you ever had that feeling of falling asleep and waking up suddenly? It happens during this phase, as the muscles relax, breathing slows down.
Deep Sleep – Stage 3 + 4 Sleep
It is the most important stage in the sleep cycle and is key to a good night’s sleep; basically, it is the deep sleep stage and will determine the quality of sleep.
After an hour and a quarter after falling asleep, you enter the restful sleep phase. Keep this in mind if you have to sleep during a long trip, as it can help you to reach your destination in good condition. It is very difficult to wake up and you are disoriented or groggy if awoken, blood pressure drops and respiratory rate drops.
During this stage, the body promotes muscle growth and repair.
REM Sleep – Stage R Sleep
This stage re-energizes your mind. It is the last stage of the sleep cycle and lasts approximately 15 to 30 minutes. The eyes move rapidly through the eyelids and there is a great deal of brain activity, as we have when we are awake, but our muscles are blocked.
Therefore, during this stage, we are prone to sleep paralysis and vivid dreams, where we are awake, but our muscles are blocked.
Why does my sleep cycle get out of sync?
Some people have problems with their sleep cycle and their brain does not keep them awake or, on the contrary, makes them sleep at inappropriate times. The reasons can be Insomnia and Narcolepsy, which a more serious affection that has to be treated by a specialist.
While insomnia causes people who suffer from it to have trouble falling asleep or sleeping. Narcolepsy causes periods of extreme sleepiness during the day and can cause muscle weakness. In both of these cases, you should see a doctor.
However, there are also times when the central circadian clock is not well adjusted to your sleep schedule and can be caused by jet lag or is experienced by people who work at night and have to sleep during the day.
Regulating our sleep cycle
Now that you know the importance of sleep and how it is shaped, to have a better rest you must implement certain measures.
Respect sleep schedules, avoid naps and try to go to bed and get up at the same time every day. If you can not sleep, leave the bedroom and do some relaxing activity, such as reading or listening to music that causes you that feeling of relaxation.
Pay attention to what you eat and drink, it is not very advisable to go to bed hungry or feeling very full, and avoid heavy or abundant meals before going to bed. Be careful with nicotine, caffeine, and alcohol.