Going to bed at night, feeling drowsy and waking up in the morning, all revitalised – what could feel better? When we haven’t had enough sleep for a while, it is all we can think of. But why do we sleep? Why do we need sleep so badly? What are the effects of sleep, other than that of recharging? Let’s have a look at the different theories:
Sleep creates memories
The importance of sleep cannot be underestimated. For one thing, sleep helps us establish memories. During a normal day, our brains are flooded with incredible amounts of information. All these facts, sensations, and experiences need to be processed and stored, and this doesn’t happen immediately – it happens while we sleep. When we sleep, the little bits and pieces of information “travel” from short-term memory to long-term memory.
Sleep helps us learn
The establishing of memories is of course essential to learning new things and skills.
When new information is introduced to the brain, it has to be “consolidated” to become a stable memory. Furthermore, you have to be capable to recall that memory after it has been stored. When you are able to do so, you have learned something new - for instance, a new word in foreign language. You might also have learned how to do something - for example, playing the guitar.
We grow while we sleep
Our bodies require long periods to revitalise and to grow muscle. During these periods, wounds are healing and tissue is rebuilding. This all happens during sleep, as our bodies “restore" what is lost while we are awake. Sleep is actually a very active period with a lot of restoration and strengthening going on. During childhood and youth we spend more time asleep to have sufficient time to grow and learn.
We sleep to save energy
When we sleep we reduce energy consumption for a while: Our body temperature drops and our caloric demand decrease. In the dawn of history, it was important not to waste any energy. So during the night when search for food was more difficult than by day, we shut down and took a long nap.
What happens during the stages of sleep?
During a sleep cycle, we go through different phases from light to deep sleep and rapid eye movement (REM) sleep, where much of our dreaming occurs. The different stages seem to play different parts in memory building and learning. It seems that REM sleep plays an essential role in the acquisition of learned material and is involved in memory storage. Motor learning seems to depend on the amount of lighter stages of sleep, and certain types of visual learning seem to depend on the amount and timing of both deep sleep and REM sleep.
Read more about sleep cycles and REM sleep.
Don’t underestimate the importance of sleep
Sleep is also said to have a positive effect on your immune function, weight loss and appetite regulation, emotional life and more, so there are plenty of reasons to adhere to your bedtime. If you have trouble sleeping for a longer period, it is important that you consult a professional to find a solution. A doctor can make a diagnosis and treat any medical conditions.
Sources
https://sleepfoundation.org/excessivesleepiness/content/why-do-we-need-sleep
http://healthysleep.med.harvard.edu/healthy/matters/benefits-of-sleep/why-do-we-sleep
