There have been a lot of studies into sleep recently, including research into why we dream and how our sleep patterns work. Studies have shown, for example, that we tend to sleep in cycles that last around an hour and a half – meaning that we are more likely to have a good night’s sleep if we plan it to last a duration that divides into 90 minute segments. So three hours of sleep (180 minutes or 2 X 90 minutes), is likely to be better than four hours. This allows us to go through the different phases of sleep and wake up when we are not in the deepest part of our sleep, which can leave us feeling grouchy and irritable. Of course, how much sleep we need varies from person to person and also changes as we get older, or depending on what we have been doing during the day. However, there is also another, more physical function of sleep that has a direct effect on your brain, and shows that a good night’s sleep won’t just rest your body, but could also help maintain your mental health!
We spend around 1/3 of our lives asleep, during which time the body is repairing and resting and we go in and out of different phases of sleep, having dreams and generally subconsciously working through things from the day. But there is also another important function at work, one which scientists are only really beginning to fully understand, and that is how your brain is ‘cleaned’ while you sleep.
Your brain makes up only 2% of your whole body, but it uses ¼ of the energy you consume. Like with anything else, energy creates waste. So, while a fire will create ash, the burning of energy in the brain leaves deposits of waste there. This waste needs to be cleaned out, and your body contains a special fluid for the job. Called ‘Cerebrospinal Fluid,’ this stuff goes right into your brain, using your blood vessels to travel along and quite literally flushes the waste away. The waste then goes into your blood where it can be processed and ejected from the body.
Your brain is the only organ in the body that uses the blood vessels as a flushing mechanism into which to put this special cleaning fluid. However, this only really happens when we sleep. While your body is resting, your brain is still at work, except it has switched tasks. Like an office that has closed for the night, the brain has its own cleaners come in to make sure things are tidy for the next day.
You know this feeling because how you will feel refreshed after a good night’s sleep, as opposed to when you stay up too long and start feeling groggy. However, this is not just about feeling better, but could also have a real impact on your mental health. Scientists have shown that a build-up this ‘brain waste’ can contribute to conditions like Alzheimer’s disease.
It would seems that sleep is not just important for resting your body, but can also have a real impact on your brain too. So, let yourself get a good night’s sleep when you can, and let your brain have a good clean!