We spend a little over 1/3 of our lives sleeping… but you have probably already heard this. However, if we speak in terms of years, perhaps the magnitude of the time we spend asleep is a little clearer: a person who lives up to 90 years of age will sleep 32 years of their life. That's a long time, isn't it?.
So, why is sleep so important? If we are going to invest so much time in it, we must know at least what makes it crucial.
Although it might sound surprising, sleep remains a great mystery even today in the 21st century with all the advances in science. This means that there is no consensus in the scientific community about why we sleep. However, several theories can shed some light on why we sleep. Some of them are the following:
> Reverse and regeneration of energy.
One of the most popular theories about sleep is that it helps us recover and conserve energy to function for as long as possible.
However, several studies have found that during sleep - although the body's energy expenditure decreases - we only achieve a reserve equivalent to 240 calories. This equates, for example, to a small bag of M&Ms or a chocolate bar like Snickers. Therefore, this theory is currently in question since 8 hours a day to get the energy that a portion of chocolate can provide us is not very convincing.
> Reparation.
This is one of the theories that have the most evidence in its favour since it has been shown that while we sleep, the body activates particular genes that are responsible for regenerating everything that wears out during the day.
The clearest example is our skin. When we sleep, we produce growth hormones and collagen. The first is responsible for repairing all the damaged skin during the day (due to exposure to sunlight and pollution). The second is in charge of keeping our skin elastic, preventing wrinkles from appearing. Likewise, when we sleep well, the blood circulation in the face is held to the maximum, preventing dark circles from appearing.
> Brain development and maintenance.
This theory has gained a lot of strength in recent years, thanks to advances in neuroscience.
First of all, it is known that sleep is essential for the proper development of the brain during the first years of life. On the one hand, while we sleep, growth hormone is produced. On the other hand, when we sleep, we consolidate all the information received during the day, which results in the development of new neural connections.
Second, various studies have shown that sleep is essential for adequately maintaining the brain. Unlike all the other body organs - which have cleaning mechanisms during the day - the brain only cleanses itself during sleep. Thus, if we do not sleep, our brain does not get cleaned.
In conclusion, although all the reasons why we sleep are not known for sure, we can be sure that sleep is essential for the proper development, functioning and ageing of human beings.
Sweet dreams!
References
Foster, R. (2013). Why do we sleep?. Recuperado de https://www.ted.com/talks/russell_foster_why_do_we_sleep
Ilif, J. (2014). One more reason to get a good night’s sleep. Recuperado de https://www.ted.com/talks/jeff_iliff_one_more_reason_to_get_a_good_night_s_sleep