There is a TED talk by neuroscientist Russell Foster on sleep which I found most enlightening. (See the TED talk here.) I also read some articles from the Sleep Medicine Division of the Harvard Medical School. Here is a summary of what I learned.

Russell Foster described sleep as the single most important behavioural experience that we have as humans. And yet we don’t really ever think about sleep. In fact, we are profoundly ignorant about sleep.

The scientists tell us that on average, humans require 8 hours sleep per day as the optimum. It is an average so some will be less and some will be more and each of us will get messages from our body guiding us as to what is right. The scientists also tell us that in the 1950’s the average was about 8 hours but today it is 6.5 hours. Huge sectors of society are sleep deprived and in my experience, it has almost become a badge of honour. See this short TED talk from Arianna Huffington as to why she believes this is wrong, based on an “ah ha” moment for her.

A critical thing for professional and others involved in logical and complex tasks is the impact that a lack of sleep will have.  To quote the Harvard Medical School division of Sleep Medicine (see full article here)

Concentration, working memory, mathematical capacity, and logical reasoning are all aspects of cognitive function compromised by sleep deprivation. However, not all of these functions rely on the same regions of the brain, nor are they impacted by sleep deprivation to the same degree. For example, the region of the brain known as the prefrontal cortex (PFC) is responsible for many higher-level cognitive functions and is particularly vulnerable to a lack of sleep. As a result, people who are sleep deprived will begin to show deficits in many tasks that require logical reasoning or complex thought.

It seems to me that accountants, lawyers and other professionals do a lot of work which fits within this category. And a lot of accountants and lawyers wear the lack of sleep as a badge of honour. Science tells us it is time to change!

Russell Foster talks in terms of poor judgment being due to a lack of sleep and quotes research showing over 100,000 car accidents caused in the USA as a result. Somewhat frighteningly, he also quotes the investigations into the Chernobyl nuclear reactor and Challenge space shuttle disasters identifying their root cause as poor judgment as a result of extended shift work.

He also shares a few other science based observations:

  • A tired brain craves things to wake it up – stimulants such as caffeine, cigarettes, drugs, alcohol.
  • If you consistently sleep 5 hours or less a night you have a 50% greater chance of being obese.
  • Sustained stress associated with sleep loss reduces immunity to disease. Common issues are type 2 diabetes and raised blood pressure and related cardiovascular concerns.

Russell Foster’s tips for good sleep

  • Make your bedroom a haven for sleep – make it dark and slightly cool
  • Half an hour before start to reduce light exposure – don’t clean your teeth in bright lights
  • Turn off phones, computers, TVs and other toys that excite the brain
  • No caffeine after lunch
  • Seek out morning light – it helps reset the cycle
  • Listen to your body


In summary:

Sleep increases (in a positive way):

  • Concentration
  • Attention
  • Decision making
  • Creativity
  • Social skills

Sleep increases (in a negative way)

  • Mood change
  • Stress
  • Anger
  • Impulsiveness
  • The use of alcohol, tobacco and other stimulants.
  • The likelihood of some mental illnesses

My own experience has been consistent with this. A while ago I made some changes to how I work and sleep and have found many of the benefits noted in the summary. I’ve also been testing my Samsung watch’s capability for sleep monitoring and it is starting to give me data that appears to be useful information about my patterns of sleep.

When faced with important decisions it might just be that “sleeping on it” could be pure genius because you will make a decision when you are at your cognitive best.