This post examines theories on why it is we need sleep and looks at the connection between sleep and learning.
Why we Sleep
Have you ever wondered why it is that humans need to spend so many hours in sleep? A recent article published by Harvard Medical School points out that while there are a number of theories surrounding our need for sleep, there is not one singular reason. Early theories centred on the ideas that sleeping through the night protected us from predators and that it helped preserve our energy. More recent theories however focus on the restorative properties of sleep and the role sleep plays in early brain development and in generating changes within the brain necessary for learning to take place.
The Restorative Properties of Sleep
Evidence shows that our bodies are rejuvenated through sleep. In fact important restorative functions such as muscle growth and tissue repair occur mostly during this time. The importance of sleep to maintain a healthy physical state is supported by studies on animals, which show that
… animals deprived entirely of sleep lose all immune functions and die in just a matter of weeks.
More important for learning is the finding that a build up of a chemical called adenosine naturally occurs in the brain during our time awake. The production of this chemical is one of reasons we feel drowsy and it can only be cleared from our system during sleep. Without enough sleep then we lose that alert feeling so important when we need to focus. Interestingly, the build up of adenosine is temporarily countered by the blocking action of caffeine leading to that feeling of extra energy we experience after a coffee or an energy drink.
Our brains undergo rapid development during our younger years as a great deal of learning takes place. That sleep is necessary for this development to take place can be evidenced by the fact that infants typically spend 13 to 14 hours a day in sleep. What has also become clear is that our brain continues to change throughout our lives and that sleep plays an important part in this process. One part of this continual development is the consolidation of memories into different parts of the brain.
Science has known for some time that when new memories are formed, they are not stable and may be lost fairly quickly. It has also been known that repetition is important in creating strong neural connections to build stable memories. A recent study reported in Science Daily has shown that sleep is also important in consolidating memories.
In the study, participants were asked to memorise finger movements (similar to piano scales). They were then given a 12-hour break. It was found that those participants who slept during their break were better able to remember the movements and were also able to perform the movements quicker and with less anxiety. Brain scans of these subjects during sleep showed that brain regions shifted during this time.
When you’re asleep, it seems as though you are shifting memory to more efficient storage regions within the brain. Consequently, when you awaken, memory tasks can be performed both more quickly and accurately and with less stress and anxiety.
From this study it is evident that there is a strong connection between sleep and learning and that a stable sleep pattern is essential for efficient learning to take place. It also suggests that catching up on sleep over the weekend will not compensate for sleep lost during the week.
Why do we sleep, Harvard Medical School
Study shows how sleep improves memory, Science Daily
Key points & significance
The findings above send out a challenge to all of us who are serious about learning. Regular, restorative sleep will enable us to stay alert in learning situations and is essential for deep learning to take place.
So what is stopping us from getting the sleep we need, and how can we break non-productive sleep habits?
A post on how habits are formed and how they can be changed will appear shortly.
Where to from here?
The post raises a number of interesting questions and gives us some directions for our own personal research. These could include:
How many hours of sleep do I actually need?
What are the different stages of sleep and in what stage(s) does learning occur?
Why do we dream?
Do animals dream?
This is just the beginning. If you find some interesting information on these, or any other sleep-related topics then why not post a comment and share with us.