The importance of sleep for your health

Sleep, much more than lying down with your eyes closed, is a complex state that is essential for maintaining the body's health and well-being. There are several studies that point to short nights of sleep as the cause of some chronic diseases, such as diabetes or cancer.

But after all, how many hours should you sleep per night?

 

This question, as well as many others that imply a generalization of the population, does not have an absolute answer: it depends on each person. There are projections of the average time, per day, that should be spent sleeping, and, in general, an adult should sleep 8 hours a night. The need to sleep decreases with age: while a baby should sleep 12 to 15 hours a day, a person over 65 will not need, and often won't even be able to, to sleep for 8 hours a day.

What are the consequences of not sleeping regularly?

 

One of the functions of sleep is the repair of blood vessels and its lack promotes an increased risk of cardiovascular diseases, such as high blood pressure, and kidney disease. Obesity and type II diabetes can also arise as a consequence of chronic lack of sleep.

Another consequence that comes from insufficient sleep results from damage to the brain, which turns out to be a loss of learning and memory capacity and reduced control of emotions, which can, in more extreme cases, lead to depressive states. Growth hormone is also produced during sleep and allows children to grow normally, and its shortage leads to developmental problems. Sleep also plays a role in supporting the immune system, making it easier to fight infections.

In addition to the individual risks mentioned, there are also risks for others: for example, it is estimated that lack of sleep impairs the ability to drive as much as being drunk. When we sleep little, the possibility of micro-sleep increases. In microsleep, you involuntarily fall asleep for a very brief period (less than 3 seconds) without being able to control yourself. In a recent study, a link was established between tragic accidents such as nuclear reactor meltdowns or ship sinkings with lack of sleep.

How does sleep happen?

 

In our brain we have “a biological clock” that tells us when we should be awake and when we should be sleeping. This natural clock is aligned with our planet's light and dark cycle and controls all of our body's circadian rhythms (which repeat every 24 hours).

The production of melatonin, a hormone essential for sleep, is stimulated by the absence of light: this is maximum at the beginning of the night in order to promote the onset of sleep. When we are exposed to light, melatonin production decreases. This feat allows you to control sleep through light.

It is not just the existence of this mechanism that leads to falling asleep. We also sleep through the action of a mechanism called “sleep pressure”, which translates the need that our brain has to sleep.

When we wake up in the morning, this pressure is practically zero, but as the day progresses, sleep pressure progressively increases, reaching its maximum value at night, when we need to sleep. As soon as we fall asleep, sleep pressure goes back to very low values ​​again.

If we take a nap longer than 30 minutes in the middle of the day, the sleep pressure will drastically decrease at that time and then there will be no time to return to the higher values ​​that lead us to fall asleep at night.

sleep architecture

Sleep is not a uniform process throughout the entire night. It develops through several phases that are organized in cycles. The sleep cycle repeats 4 to 6 times a night. This is divided into non-REM sleep and REM sleep. REM means rapid eye movements (rapid eye movements).

Non-REM sleep, which lasts the longest and comes first, consists of several stages:

- Phases of superficial sleep (transition from wakefulness to sleep);

- Deep sleep phase, which is very important for its restful and restorative action.

REM sleep alternates with non-REM sleep. During REM sleep our eyes move, but the rest of the body is paralyzed while we dream intensely, our breathing accelerates and brain activity is very similar to what we have when we are awake.