Brain Matters: Why sleep is important

Throughout my working life with PwC, Hill & Associates and Boston Consulting Group, sleep was never a priority. The saying, there are not enough hours in a day was something I could identify with. Of course, I was always reminded that sleep was important. But I seldom practiced what I was told about sleep.

Over the past year, following my decision to retire, I have been learning again -at my own pace and really enjoying it. I am learning not to pass exams or for career reasons. I am learning to expand my knowledge. And when one is learning for fun, it really is fun! I enrolled with Yale University and took their online program on The Science Of Wellbeing. I also enrolled with the Brain Academy to learn about how the brain affects our behaviour. Recently I enrolled with Sloan MIT to expand further my knowledge of neuroscience.

I would like to share with you some of my learnings.

Learning #1 is the importance of sleep.

When we sleep, a few things happen.

Firstly, our hippocampus (that is our memory) updates everything we learnt during the day.?Think of the brain as a supercomputer which needs to go through a daily “batch update” routine. Yes, whatever we are told during the day; whatever we read; whatever we see is firstly stored in our short term memory. But at night, when we sleep, the brain does it daily update to transfer these items into our long term memory. If we don’t get enough sleep, chances are some of this important data does not get transferred to our long term memory and we will forget these matters very quickly. I remember when I was at school and studying for our final exams, a friend told me that if I slept with a textbook under my pillow, the knowledge from the book would be transferred to my brain. Off course this was not true but then again what he was saying was not that far off the truth. Everything I learnt during the day actually got cemented in my memory whilst I slept. This kind friend of mine was trying to ensure I got a decent night’s sleep and did not burn the midnight oil. Bless him!

Secondly, during the course of the day, our brain cells are creating waste material, a kind of toxin which if not cleared can make us feel ill. Trying going without sleep or ?just having a little sleep for a couple of days and you will feel nausea. This is because of the build up of this waste material in our brain. When we sleep, our brain activates a self cleaning mechanism. A liquid called cerebrospinal fluid (CSF for short) is released and it goes through the brain like our own internal vacuum cleaner and removes all the toxins that have built up during the day.?So you can guess -insufficient sleep and the toxins are left in the brain. If you are constantly short of sleep, the toxins build up and you eventually will feel unwell. I know. It has happened to me -too many times for my liking. But until now, I never knew the medical reason for this.

Thirdly, we lose about 3 million brain cells a day! If we don’t do something to create new brain cells to replace the ones we lose, by the time we are fifty years of age, our brain will be operating at a suboptimal level. Fortunately neuroscientists have discovered that we can create new brain cells -it is called neurogenesis. There are a number of ways for neurogenesis to occur. Sleep is one. If you do not get sufficient sleep, you will be on your way to ensuring that the 3 million brain cells you lose daily are not being replaced. That explains why babies sleep a lot when they are first born. Whilst they sleep, millions of brain cells are being developed. At our peak, we have almost 90 billion brain cells.

So how much sleep do we need? Well, try this when you can. When you next sleep, don’t set the alarm clock to wake you. Once the brain has done its nightly maintenance and update, it will send you a signal to wake up. Yes, that is how the brain operates. And that will tell you how much sleep you need. Yes we all have instances when we need to work long hours. But it is not sustainable -unless you don’t mind having a memory that is older than your biological age.

The brain is a supercomputer. It processes something like 30GB of data daily. When our computer is faulty, we can call the helpdesk and ask them to fix it. Perhaps it needs more memory; perhaps the microchip needs to be replaced. We don’t have that luxury with our brain. Once it is faulty, it cannot be repaired. So take care of it.

Next week I will share some fascinating data about the brain. Join me for Brain Matters.

Hope this has been helpful.