Sleep, learning and creativity

Workers and organisations both benefit when people sleep well. 

Research shows sleeping 8 hours a night can improve performance by 20–40% depending on the aspect of performance being studied. Performance testing includes mathematical tests, grammatical reasoning, decision making, vigilance tests, psycho-motor testing, speed and accuracy tests, and many more. 

Sleep also improves emotional control. We have all experienced—in ourselves or others—the emotional impact of sleep deprivation. It makes people irritable and snappy, withdrawn and uncommunicative, or moody. 

Sleep can improve our performance and emotional control.

Sleep and learning

“You can’t cheat sleep on either side of the learning equation.” 

That is the message from Professor Matthew Walker (Professor of Neuroscience and Psychology at the University of California, Berkeley, and Founder and Director of the Center for Human Sleep Science).

You need good sleep before learning so your brain is ready to absorb new information and lay down new memories. You also need good sleep after learning to consolidate these new memories. Sleep helps move new information from short-term storage to long-term storage. Sleep improves our memory; 8 hours sleep per night improves the ability to remember what we have learnt the day before by 25% compared with 6 hours sleep. 

REM and non-REM sleep make us good learners

Both rapid eye movement (REM) sleep and non-REM sleep appear to help with learning:

• REM sleep is linked with procedural memory (e.g. remembering a sequence of steps). It also links the information you recently learned with your existing knowledge. 
• Non-REM sleep is linked with declarative memory (e.g. remembering basic facts and statistics). 
• You need 7–9 hours sleep per night to get the full benefit of both these types of sleep on learning. 

Sleep and creativity

Creativity involves connecting loosely associated ideas, and good sleep strengthens this ability. Sleep seems to allow us to link pieces of information that our daytime rational brains see as separate. Saying “I’ll sleep on it” when we have a problem came about because of the brain’s enhanced ability to link information when we sleep. 

Non-REM sleep allows our brains to restructure and reorganise information. And then during REM sleep, we connect things that did not seem connected. It allows us to consider information and solutions from different perspectives and without preconceptions and prejudices. 

According to Professor Walker:

• Deep sleep is about knowledge—gathering information and holding on to it.
• REM sleep is about wisdom—knowing what it all means when you fit it together.

Sleep and productivity

When we want to get more work done, the temptation is to work longer hours because it seems to make intuitive sense. However, with humans, it is not that simple. Working longer hours usually occurs by sacrificing time to sleep. And combining sleep deprivation and long hours lowers productivity.

Human productivity is not a linear relationship of hours of work and productivity. Studies show that after 50 hours of work per week, the amount of ‘effective work’ starts to decline. For example, someone working 70 hours a week may get only 50 hours of ‘effective work’ done. In addition, if someone is sleep deprived before they start working extra hours, the decline in effective work starts at 45 hours of work. 

This decline in effective work is not a good return on invested time for either the worker or the organisation. The good news is that if a person is well rested, and hours of work are kept below 50 hours per week, then productivity remains effective for most of the hours worked. 

If we want to remain productive, it's important to get sufficient sleep and allowing time for leisure activities, social activities and exercise.

Sleep and mood

Sleep deprivation can make a person grumpy and irritable, or unusually quiet and withdrawn. In other words, sleep affects our mood. So why does it happen? 

It seems that without sleep, we revert to a more primitive way of using our brains. When people are sleep deprived, the amygdala—the primitive part of our brain that controls our ‘fight or flight’ response—reacts without the normal constraint that comes from the more sophisticated parts of the brain, such as our pre-frontal cortex—the part of our brain involved in intelligent thought and interpersonal social relationships. 

Further, when we are sleep deprived, we can experience increased mood swings—from very happy to very sad, from very angry to very anxious. And our ability to quickly assess and interpret social situations and act accordingly, is significantly reduced. So the sleep deprived person can act in an emotionally uncontrolled manner and cannot recognise signs that this is upsetting people around them. This means sleep deprived people can be challenging to work with. 

In the workplace, tasks that rely on good teamwork can be at risk when people are sleep deprived. 

Sleep and physical skills

Evidence shows sleep improves physical motor skills that require fine motor coordination, hand–eye coordination, rapid motor response, strength and endurance. In fact, studies show the brain ‘practises’ skills during sleep and consolidates the memory of how to do something. People taught a skill and then allowed to sleep can improve performance by up to 20% with no further practice. 

The most critical time for this skill consolidation occurs in stage 2 sleep, during the last 2 hours of our normal 8-hour sleep period. This is particularly important for athletes, many of whom have to get up early to train. Taking away the last 2 hours of sleep may inhibit their to hone the skills they are working hard to acquire.