How Hormones Affect Sleep Quality?

Let’s know how hormones affect sleep quality? In our busy world of waking life, we literally burn up our tissues faster than we renew them.

Living tissues are being worn out and renewed all the time, and across an average of twenty-four hours, we keep the two processes in balance.

The wearing out and the renewal continue both by day and by night, but the wearing out is more predominant by day and the renewal by night.

It is not only so many hours of sleep we need, we need to sleep of good, refreshing quality. Most people feel refreshed by their sleep.

But others are less fortunate and feel that somehow they are not fully restored by their night’s sleep; they feel less vigorous by day and feel that their cars have remained with them throughout the night.

We can record the electrical brain wave of volunteers with this problem, and in fact, most of them differ little in their hours spent asleep and the number of times they wake up from most other people of their own age.

In the last few years, however, we have begun to make measurements of just how restorative sleep maybe, and it looks as though many of the people who feel that they sleep poorly, although they may sleep as long as other people, really do have less of the kind of sleep that restores; at least as far as we can judge from their hormones.

Some poor sleepers, for example, have unusually high night-time levels of the hormones that hinder the renewal of the brain and body tissues. 

How hormones affect sleep

The scientist always wants to make objective measurements. Tiny pieces of skin can be cut off and the rate at which skin cells are multiplying and renewing themselves at any one time can then be measured.

Sure enough, human skin cells renew themselves faster during the time of sleep. The same seems to be true of human blood cells. And we know from studies with animals that every tissue of the body from the brain to the sole of the foot renews its structure faster during sleep.

What we can do in human beings, is to try and understand the body’s controls of the restorative function of sleep. Very important are the hormones, or chemical messengers, of which very small amounts circulate in our blood.

Some of these hormones came from the pituitary gland at the base of the brain and their release into the blood is controlled by the workings of the brain. Other important hormones are released from the adrenal glands, which are situated just above the kidneys.

The hormones of wakefulness

Adrenaline (epinephrine)

This is one very important hormone released from the adrenal glands in large amounts while we are awake, but hardly at all while we sleep.

Small quantities of adrenaline are present in the blood all the time that we are awake, but in moments when there are extra demands upon us, and most of all when we are under stress or frightened, the adrenaline rises to high levels.

It enables our muscles to exert greater power, using up enormous quantities of their energy reserves in a very short space of time.

How hormones affect sleep quality

The hormones of wakefulness – adrenaline (epinephrine) and corticosteroids- give us pep to cope with emergencies while we are awake, but hinder the renewal of the body’s tissues. They are released into the bloodstream from the adrenal glands, near the kidneys. The adrenaline is triggered by nerve messages from the brain; the corticosteroids, by a control hormone from the pituitary gland.

Dealing with emergencies takes priority over everything else. In emergencies, the body is heedless of wearing out the tissues at a faster rate and holds in abeyance the processes of restoration, including the digestion of food and the eventual use of food materials for rebuilding the body.

It is not just the muscles that are working with greater force during emergencies, giving priority to needs other than the manufacture of the proteins the building blocks that make up the structure of the tissue the same things are happening in the brain too, as far as we can judge.

Adrenaline positively inhabits the formation of new protein tissues and this fact by itself makes wakefulness a time of reduced manufacture of what is needed to keep that tissues renewed compared with the time of sleep.

Adrenaline has a close relative, a hormone called noradrenaline (norepinephrine), and the amount of this in the brain is greater by day and helps us to be more effective in dealing with problems, but it too reduces protein renewal. 


The adrenal glands release other hormones into the bloodstream that are called corticosteroids. These corticosteroids seem to complement the adrenaline by providing a sort of steadying back-up influence.

Although adrenaline is being released all the time and especially while we are awake, it comes in sudden high-intensity spurts according to the moment-to-moment challenges that we face. In contrast, corticosteroids provide a general background to improve our waking capacities.

They are almost absent during the early night, but towards the latter part of the night’s sleep, they begin to be found in larger quantities in the blood, until they reach very high levels soon after our usual time for waking up.

They seem like a morning tonic, a sort of pick-me-up that is not needed so much during the afternoon and evening.

The corticosteroids too, like adrenaline, positively inhibit the manufacture of the new protein that is necessary for tissue renewal.

We can see then that the main hormones on wakefulness, while they are very important in enabling us to meet the demands of the day, also ensure that achievement while we are awake has priority over providing a balm to our minds or renewal of our bodies. 

The restoring hormones of sleep

When we go to sleep, the renewal of the body’s tissue, provided by the manufacture of fresh protein, can proceed faster; and not merely because of the relative absence of the waking hormones, adrenaline, and corticosteroids, but because is positively encouraged by the presence of new hormones released into the bloodstream while we are asleep.

There are several of these body-building, or anabolic, hormones. Testosterone, a male hormone, is perhaps best known as a bodybuilding hormone that has been used illegally in attempts to interfere with nature and enable international athletes to perform with greater prowess; and testosterone is among the hormones that rise in concentration in the blood during sleep.

Among the other is a hormone that is known as growth hormone. The growth hormone really does what it says, it makes tissue grow faster. 

Growth hormone

The manufacture of new protein material for growing latter is the same process as the manufacture of new protein during the day. The growth hormone is released by the pituitary gland when it is told by the brain that sleep is present.

The mechanism is a very old one in evolutionary terms, for it has been discovered to exist in fishes. As a consequence, although there is quite a lot of growth hormone in the blood while we are awake, the amounts are much higher during sleep.

If you were to go without sleep for a couple of days, when at last you fell asleep, the growth hormone would really rush out into your bloodstream to help the renewal of the tissues.


The hormones released by the pituitary gland into the bloodstream when we sleep encourage the renewal of body tissue that has been worn out during the day.

Helped by the low levels of the daytime hormones-adrenaline (epinephrine) and the corticosteroids while we sleep, the bodybuilding hormones, like growth hormone, really can do their best for us at the time of sleep.

It has actually been found that in children who have a deficiency of growth hormone, the growth process can better be helped by giving an injection of growth hormone just before they sleep that by giving the same amount of growth hormone as an injection at breakfast time.

Although we have said a lot about the hormones, they are only part of the chemical system controlling the body’s renewal.

Very simple forms of life that do not have hormones circulating in the bloodstream, but which take in food during the daylight hours and rest during darkness, also have a predominance of protein manufacture and tissue renewal during their times of rest, and this is because when the living cells of either simple creatures or complex ones like of the body are not geared of making a protein or for restoration, and it is only when the energy levels within the cells can rise through rest, that renewal can again take place. 

Unrefreshing sleep: the hormones working at the cross- purpose

We have already explained about our biological clocks and have emphasized that the keeping of regular hours for going to bed and getting up helps sleep to feel good and people to feel happier and more energetic by the day.

This is because regular hours help to keep the hormones of sleep and wakefulness operating in harmony that is each working with each other and at the time of the twenty-four hours when each can best perform its particular function.

It is common to have a night’s sleep, after which you feel tired and unrepressed; the cause may be partly traced to the keeping of regular hours.

This can disturb the biological clock and make the two sets of hormones work counterproductively at cross purposes. The occasional late night does not cause any long term problem with the balance working of these hormones, but many people nowadays have jobs that require them to lead an unnatural life for getting up and going to work.

A close look at their sleeping patterns tells us about the way hormones can make sleep unrefreshing. 


Aircrew has to fly around the world and keep changing their pattern of life their times for eating and for going to bed and getting up, according to local clock times.

Nurses and policemen have always had to sacrifice conventional hours of eating and sleeping and for being with their families; and nowadays, when it may be wasteful not to keep expensive industrial machinery in use steadily around the clock a higher proportion of the population is called upon to undertake shift-work.

working night shift

Working night shifts disturb the balanced working of the hormones of sleep and wake fullness. As a result, many shift workers feel less refreshed by their sleep.

In theory, if you worked a regular night-shift you could change your whole pattern of life and readjust your biological clock so that you got your highest temperature at night and your lowest by day, and then you would be just as bright and efficient at night as you are by day while you lead a regular life of daytime work.

In practice, this does not happen because people have days off and on those days they like to mingle with their families and friends go to social events, and do all the other things that their family and friends are doing during the day.

As a consequence shift workers never really make a full adjustment of any kind of regular twenty-four-hour pattern. Different individuals rest differently to shift work, but for some, it is certainly a cause of feeling below par both physically and emotionally.

If you look at the diagram you can understand better how shift work makes it more difficult for the body to give us good restful and restorative sleep.

In the first place it may be difficult to get to sleep at an unnatural time perhaps with strong daylight and noisy children and what sleep comes is more likely to be disturbed by noisier conditions.

A look at the hormone arrangements within the body shows that the daytime hormones the corticosteroids and the adrenaline that favors the breakdown of tissues and not their renewal rise and fall every twenty-four-hour according to a circadian rhythm.

If you suddenly go on to the night shift, then the adrenaline and the corticosteroids will not rise quite as high during the day while you are doing your best to sleep but raise they inevitably will.

Weeks of a regular routine would be needed to switch them round completely to being low by day when the night shift worker would be hoping to sleep, and in practice, as we have said this does not happen because of the demands of family and social life.

The bodybuilding hormones of sleep, however, are not governed by a circadian rhythm but by sleep itself. Just by going to bed and lying down does not mean that more growth hormone will be released into your bloodstream.

You have got to sleep and sleep deeply. When therefore you go on to night shift working and go to bed at 9 am provided you fall into a deep sleep the growth hormone will certainly be released into your blood but now it’s good effects will be counteracted all the time you are asleep by the high levels of adrenaline and corticosteroids in the blood which would not have been there having your deep sleep and your growth hormone come to you in the middle of the night.

Normally we have a very sensitive relationship such that the hormones that favor lively achievement and inhibit the renewal of body tissues are kept out of the way while we sleep.


The night shift changes the rhythm of the sleep hormones. Consequently, their restorative effect during sleep the next day is reduced by the high levels of adrenaline and corticosteroids, whose rise is governed by a twenty-four-hour cycle, not by being awake or asleep.

Evolution did not include shift work rotas. Earlier we said that individuals differ and some people do find it more difficult to adjust to shifting work.

Middle-aged and older people fall less easily into a sound sleep at any time than young people and they are also less adaptable in facing sudden clock changes if they fly around the world and again they find it less easy to get satisfactory sleep if they go on to shift work.

Board generalizations like these do not apply to everyone; you may be able to point to someone among your friends who is middle-aged and finds no problem at all in being a shift worker but he may be just the lucky exception.

All life is compromised and we have to accept the disadvantages as well as the benefits of our modern society. We are not advocating that people stop doing shift work but we do urge that there should be a better understanding of the difficulties that some people face when they are asked to cope with shift work.

They may become not only less vigorous but also less efficient, less happy, and less emotionally stable. They should not be condemned out of hand; it may just be that they have stricter biological clock and hormones systems.

Once you have entered the routine of shift work there is little you can do to counter the unwanted effects of your hormones working at cross purpose; there are no medicines that will help. One thing that will make their effects worse and which should be avoided is the heavy consumption of alcohol.

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