Go to bed! The effects of a lack of sleep

Matthew Walker writes in his fantastic new book ‘Why We Sleep’ that two-thirds of adults in developed nations fail to obtain eight hours of sleep a night. This short article is to give a flavour of the effects of a lack of sleep, and what medical treatments are being developed as a result.

Lack of sleep has an adverse affect on literally every biological system in the human body.

A study quoted by Walker (2017) shows that men who sleep 5 hours a night have much smaller testicles than those who sleep 8 hours or more. Those men who routinely sleep 5-6 hours a night has a level of testosterone of someone 10 years older. This gives an insight in to the impact of sleep on hormonal regulation.

The amygdala is a brain structure responsible for strong emotional reaction. In sleep deprived people, you see around a 60% increase in responsiveness, leading to a lack of regulatory control of emotional response and increased extreme response. You only need to speak to an Oxford or Cambridge University student after pulling an ‘all-nighter’ to find this out for yourself.

The hippocampus – the ‘memory inbox’ of the brain – is particularly affected by lack of sleep. Without sleep, the memory circuits of the brain become ‘waterlogged’ preventing you to absorb new information. For this reason, sleep is incredibly important in education. Schools in the town of Edina, Minnesota, decided to try an experiment to test this. They shifted their school start times from 7.25am to 8.30am, and measured the difference for SAT scores. The result was a positive increase of over 200 points – enough to open up a different tier of university.

As we age, our cognitive ability declines. Another physiological signature of ageing is that sleep also gets worse, especially the deep quality of sleep. It has been discovered that these two aspects of ageing – cognitive decline and worsening sleep – are actually interrelated rather than simply correlated. Most recently discovered, a lack of sleep is a contributive factor to Dementia and Alzheimer’s disease (see the bibliography below for some of this evidence).

These discoveries are startling and frightening, but they are also exciting because they allow researchers to develop ways to do something about it.

What is now in the pipeline of being approved for public use is a technology called ‘direct current brain stimulation’, in which electro-pads are applied to the head and a small amount of voltage is inserted to the brain. Current tests of this technology are very promising, showing a measurable impact to physiology. If you apply this to healthy adults, for example, deep sleep brain waves can be amplified, and you can nearly double the amount of memory benefit.

Sleep is a non-negotiable biological necessity. The decimation of sleep is having a catastrophic impact on our health. Sleep is also a fascinating realm of study, in which new discoveries are occurring all the time. These discoveries are, in turn, leading to the development of new treatments, such as ‘direct current brain stimulation’.

Applicants for Psychology, Human Sciences, Medicine, or Natural Sciences are encouraged to explore this topic further and pick up a copy of Matthew Walker’s book, ‘Why We Sleep’ (2017).