Annotated Bibliography

In Context

122 www.thelancet.com/neurology Vol 17 February 2018

It was a dark, autumnal, Monday evening, and for many of the audience at the Royal Institution of Great Britain (London, UK), the benefits of any extra sleep over the weekend probably felt all but over after the first day back at work. Rather than opting for an early night, however, we gathered to listen to a public lecture by Matthew Walker (Professor of Neuroscience and Psychology, University of California, Berkeley, CA, USA), entitled Why we sleep. As Director of the Center for Human Sleep Science, Walker’s research aim is to uncover the effects of sleep in health and disease, but he is also active in science communication: giving talks and contributing to television and radio, and having published a book in October, 2017, with the same title as the lecture.

The lecture title was somewhat misleading, because, in his own words, Walker spoke not about the benefits of sleep, but “the alarmingly bad things that happen” when you do not get enough. James Gallagher (health and science reporter, BBC News) also remarked in his introduction to the lecture, “I hope everyone in here does actually sleep, otherwise you’ve got really big problems.” Walker opened with a light-hearted statement about the relation between short sleep duration and small testicle size in men. However, the tone of the lecture became progressively unsettling for anyone who does not sleep enough—probably most of the 200 people in attendance.

To illustrate the effect of sleep on the brain, Walker used the analogy of the brain as a computer. Not only has research suggested that sleep is needed after learning to “save” new memories, but we also need sleep before learning to prepare the brain for new information. In studies of 8 h sleep per night versus deprivation, brain activity on MRI showed a 40% deficit in new memory formation in individuals who had no sleep.

As well as these short-term effects, Walker mentioned the effects of sleep on ageing and dementia. Rather than parallel phenomena, cognitive decline and reduction in sleep seem to be substantially inter-related. Thus, intervening to increase duration and quality of sleep might help prevent such sleep-related problems. To this end, Walker and his colleagues are developing commercially led interventions that improve sleep quality. Using direct current stimulation in a research setting, a small voltage is applied to the brain during sleep, which can amplify brain waves during deep sleep, apparently doubling the memory benefit of sleep. Improvement of memory and learning in diseases such as Alzheimer’s disease is Walker’s moonshot goal. However, he cautioned that devices that deliver brain stimulation are not approved for clinical use, but hopes that they might become available in 3–5 years.

Walker also gave examples of the benefits of allowing young people to sleep more. Delaying school start times in various areas in the USA has been associated with better academic results, reduced behavioural problems and truancy, and even increased life expectancy (probably due to a reduction in traffic accidents). He is, therefore, strongly for a proposed delay in UK school start times to 1000 h, arguing that “when sleep is abundant, minds flourish.” Walker proceeded to describe various detrimental effects of poor sleep on health, including psychiatric, metabolic, and cardiovascular disease; immunity; and cancer. The lecture ended with a self-professed “soapbox rant”, in which he concluded that sleep is not an optional lifestyle luxury, but a non-negotiable, biological necessity. He warned of a “silent, sleep-loss epidemic” in industrialised countries, which could prove a major public health challenge in the future.

With exponential advances in technology creating a 24-h culture, it is difficult not to agree with Walker’s counsel. As he points out, no other animals deprive themselves of sleep like us. As such, we have yet to compensate for loss of sleep through evolutionary changes, so what can we change? Our behaviour. Walker listed five factors that affect sleep: temperature, technology, light exposure, anxiety, and alcohol and caffeine. Like exercise, paying attention to these factors is something we can all attempt to do to slow seemingly inevitable ill health and cognitive decline associated with sleep loss. But as anyone who has trouble sleeping or any clinician working with people with sleep disorders will tell you, getting more sleep is easier than it sounds.

The audience’s wonder at the benefits of sleep was audible, but questions remain about how these findings can be translated into treatment. Clinical studies that test scientific theories about improving sleep are needed, but in the meantime, advocacy is another approach. And that is what Walker is doing: advocating good quality sleep for better health by communicating his research and views to the public.

As Walker acknowledged, his lecture was rather bad news. But, perhaps we can feel empowered by his message: many aspects of health are affected by how well we sleep—a factor that we can potentially change. At the end of his lecture, the speaker finally wished the audience “good night, good luck, and…sleep well”. Not only to feel bright and alert tomorrow, but perhaps also to contribute to a healthier life thereafter.

Cheryl Lai

Lecture Prescribing sleep for better health

Ch er

yl L

ai

Published Online November 17, 2017

http://dx.doi.org/10.1016/ S1474-4422(17)30398-8

For more on the lecture see http://www.rigb.org/whats-on/ events-2017/september/public-

why-we-sleep

For more on Matthew Walker see https://www.sleepdiplomat.

com