You will probably be familiar with some effects of sleep deprivation — underperforming, being error-prone and snappy — but may be less familiar with some of the more insidious effects of sleep loss, which include impairment of immune responses, an increased risk of cardiovascular and metabolic disorders and cancer, and a link with Alzheimer’s disease. Sleep, says Professor Matthew Walker, the author of this engrossing book, should be regarded as the ‘pre-eminent force in the health trinity, along with a balanced diet and exercise’.
Walker is no slouch, and is very persuasive. He is Professor of Neuroscience and Psychology and Director of the Sleep and Neuroimaging Laboratory at the University of California at Berkeley, and previously worked at Harvard. He is a good communicator — his writing is accessible and he uses metaphors and analogies effectively to get across new and complex ideas. There is sometimes a bit too much of the ‘you’ll never believe this …’ and occasionally his descriptions of brain activity verge on the anthropomorphic — but perhaps he is right about that too.
He sets the scene extremely well, with lucid explanations of the roles of melatonin and adenosine in establishing the circadian rhythm and the functions of REM and non-REM sleep. He is interesting on the different, fixed circadian rhythms of ‘morning larks’ and ‘night owls’, and the adjustments that education and business might advantageously consider making for them. I thought that the siesta culture throws a bit of a spanner in the works, and that he didn’t really deal adequately with this different but widespread sleep pattern.
The book is quite fact-packed, and Walker realises this, even saying that if it lulls the reader to sleep he would be quite happy, and advocating dipping in and out of the chapters in no particular order. You will be able to choose from accounts of the benefits of sleep for the brain, the physical impacts of sleep deprivation, how and why we dream, sleep disorders, and dealing with sleep disturbances.
The effect of temperature on sleep is interesting. Although a warm bath is generally regarded as a prelude to a good sleep, Walker is clear that a drop in core body temperature is associated with good sleep quality, and that an ambient bedroom temperature of around 65°F is ideal for most people.
Walker sets out his stall for a sleep revolution in the final chapter. His recommendations comprise attention to domestic temperature and lighting, personal and public education, organisational change such as providing incentives for healthy sleeping, and creating flexible shifts, and, at a societal level, introducing criminal penalties for damage and death caused by driving when drowsy and, perhaps most importantly, systematising the awareness of the health benefits of consistent and plentiful slumber.
- © British Journal of General Practice 2018