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Sleep: Role of Melatonin in the Circadian Rhythm

Sleep is a complex process where many elements play a particular role. Among them, the role of melatonin, also called sleep hormone, is crucial.

Insomnia, multiple awakenings, difficulty falling asleep … Sleep disorders affect between 25 and 40% of people over 55 years. But the rate of melatonin, the hormone essential for a good quality of sleep, tends to decrease with age. Melatonin: what is it? What is circadian rhythm? What are the tips and methods to sleep well?

In this article, find out more about sleep hormone or melatonin – and circadian rhythm. Also, find at the end of the article some tips and methods to sleep well.Role of Melatonin

Role of Melatonin in Sleep

Melatonin, also known as the sleep hormone, is a hormone naturally produced by the epiphysis (or pineal gland, in the center of the brain) which plays a crucial role in the sleep-wake cycle.

Normally, it is released in case of darkness (especially at nightfall) to facilitate falling asleep. The secretion reaches a peak between 2 and 4 o’clock in the morning then decreases during the second half of the night, to prepare for the awakening.

Essential for the body, melatonin provides regular sleep cycles and also helps the body adapt to seasonal changes.

Melatonin is naturally present in the body and allows the regulation of the internal clock on the sleep-wake cycle.

Light / dark alternation (or day/night) is the major synchronizer of the system. Thus, when night falls: the secretion of melatonin increases which favors falling asleep.

But sometimes, your melatonin secretion is delayed and you have trouble falling asleep, so a melatonin-based dietary supplement can help you to not miss the tickle of falling asleep and “resynchronize” your system.

Melatonin in Detail

To understand melatonin, it is necessary to go through the brain, and more precisely by its base, where the hypothalamus is located. It is indeed in this part of the brain that the process of watching and sleeping is regulated. Nerve cells or neurons connect the retina, a region of the eye that is sensitive to light, the hypothalamus, and the pineal gland that secretes melatonin when it is dark. It is only in the dark that melatonin is released into the brain. This hormone reaches its maximum level at 2 o’clock in the morning. Its production can be slowed down, or even completely suppressed by the light.

Light and Melatonin Go Hand in HandSleep in Light

It is the alternation of daylight and the darkness of the night that will allow the sleep/wake cycle to be realized. In some blind people, for example, the sleep/wake cycle is disrupted. On the other hand, when someone is subjected to strong light in the morning or in the evening, there is a shift in his sleep. Strong light in the morning, for example, causes advanced sleep schedules: we fall asleep earlier and wake up earlier the next day. Conversely, strong light in the evening delays falling asleep at night and waking up in the morning.

Role of Melatonin in the Circadian Rhythm

Melatonin is a substance naturally produced by the pineal gland in the brain and regulated by the day/night cycle.

It is secreted preferentially during the night, usually, with a peak around 3 am, and then its secretion decreases gradually until waking.

Its role is to synchronize the circadian rhythm that is to say the sleep-wake cycle.

Did You Know?

Large sleepers have longer than average melatonin secretion time, which is why they feel they need more sleep1 to feel rested.

The blue light of screens (computers, smartphones…) delays the secretion of melatonin and therefore the desire to go to bed. To avoid therefore the evening to sleep well!

How does melatonin influence our circadian rhythm and therefore our sleep?

We must know that we do not all secrete melatonin in the same way. Indeed, in some people, the secretion may be a little weaker or almost absent.1 Here is an example of the secretion of melatonin in an individual. On average, its secretion begins around 19h in the evening and extends until 3:00 to -4:00 in the morning.

* When it is difficult to fall asleep, the secretion of melatonin is shifted sometimes until 3h-4h in the morning, delaying falling asleep. (Source: Claustrat B. Melatonin and sleep-wake disorder sleep medicine, 2009; 6: 12-24)

* Thus an external intake of melatonin can help you fall asleep faster and restore a normal sleep/wake rhythm. (source: Scientific Opinion on the substance of a health claim related to melatonin and reduction of sleep onset latency).

Circadian Rhythm and Sleep

We all have within our brain an internal clock that can regulate our biological rhythms, this is called the circadian rhythm.

It is defined by the alternation between the waking state, which corresponds to the period of the day during which one is awake and sleep, a period during which one sleeps.

The circadian rhythm controls a set of parameters such as body temperature, the secretion of cortisol, feeding behavior but especially the secretion of melatonin. Indeed, melatonin, a hormone naturally present in the body, produced by the pineal gland is regulated by the day/night cycle. It is secreted during the night with a peak usually around 3 am. Its role is to act as an endogenous synchronizer of circadian rhythms, rhythms of temperature, and sleep-wake in particular. She will, therefore, inform the organization on the position of the day/night alternation in order to put the latter in phase with the environment.

The sleep/wake rhythm is the one that marks our daily life, with an average duration of 24 hours.

Why Does the Body’s Body Temperature Drop During the Night?

When you wake up in the morning, you have trouble getting out of bed, you are cold. Our internal clock coordinates the activity of our body temperature by lowering it to a minimum during the night.

Did You Know?

The circadian rhythm also regulates the secretion of cortisol. The latter reaches its highest peak in the early morning and contributes to the overall activation of the body. That’s why we feel very fit.

Tips and Methods for Good Sleeping

To sleep well, it is first of all to respect a certain number of rules of hygiene of life and to adapt to its environment.

BedroomBedroom Idea

It must be calm, well ventilated, away from strong lights, at a cool temperature (18 ° C), clean, relaxing, and soft … To sleep well the bed must be comfortable: remember to change mattresses regularly.

The Food

It is an essential rule of life: you must eat varied and balanced to sleep well. It is important not to eat too heavy meals at night as they delay falling asleep and sleeping with the stomach still full can promote acid reflux. Alcohol is also a false friend of sleep because if it promotes sleep, it disrupts the sleep cycle and worsens snoring. Excessive consumption of coffee, tea, or caffeine soda is also discouraged, especially in the afternoon! Try to keep your dinners at regular times (2 hours minimum before bedtime) and plan a meal not too light (hunger can wake up) nor too rich (because it might prolong digestion until late at night).

Physical Activity

The sport has positive effects on sleep by reducing tension.

The most positive effects are felt if the physical activity session is between 4 and 8 am before bed. But even if you practice a sport in the evening, after work, for example, the benefits remain interesting: the sleep time is increased, the wakes less nocturnal, only the time needed to fall slightly increases. The recommended duration is one hour, the intensity should not be too important, and the practice should be regular.

The Bedtime Ritual

Arrange to go to bed at about the same time every night, to gently impose the right rhythm on your body. When you feel near the first signs of fatigue (yawning, heavy eyelids …), do not fight and do not miss the train of sleep. Direction – the room. You can then take a book or a magazine and read a few pages; it is for some people a little habit that helps to fall asleep. Find your little ritual! But in any case, avoid screens and activities too stimulating before going to bed.

To summarize the tips and methods for sleeping well: the 10 commandments of sleep:

To fall asleep and sleep well, it is necessary that certain conditions are met. In order to understand how to sleep better, we have prepared the 10 commandments of sleep to which you will not derogate.

1. The excitants at the end of the day, you will avoid: some drinks such as coffee or tea contain caffeine, a stimulant that can prevent you from sleeping well. Prefer herbal tea at the end of the day.

2. Your electronic devices, you will disconnect (phones, computers, televisions …): a lit screen, that is to say, a bright light sends to the brain awakening signal that inhibits the secretion of melatonin and delays sleep.

3. You will put yourself in sport: athletes have a better sleep. Indeed, the sport allows the secretion of endorphins which releases the tensions. Privilege activities but not before falling asleep.

4. Microphones naps, you will do: 10-20 minutes and not after 15h; they help promote concentration and do not prevent you from falling asleep at night.

5. Your body, you will listen: watery eyes, yawning are signs that your body sends you to bed, if you resist, you may miss the boat and fall asleep very late. Do not fight against sleep and do not stay indefinitely in bed in the morning.

6. Exclusive, your bed will be for sleep and hugs and not for hours watching TV or computer!

7. Dinner too rich or too watered, you will avoid so that your body does not begin the process of digestion during your sleep and prevents you from falling asleep. Diet plays a crucial role in sleep.

8. Before going to bed, you will relax: it is advisable to read before bed to institute a form of ritual. On the other hand, sustained intellectual activity, such as reading a complex book, taking notes, etc. stimulates brain activity and harms sleep.

9. A regular rhythm, you will adopt: try to sleep at the same time each day so that your body takes the pace. A short night is not compensated by a long night the next day, so it is necessary to keep a certain regularity so as not to be lacking sleep.

10. And if you wake up at night or you cannot sleep, you will get up: leave the bed, do an activity and when the desire to sleep reappears, go quickly join the arms of Morpheus.

Want to know more about the role of melatonin and its benefits? Then I suggest you read the next book.

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