The Truth About Sleep? We’ve Known How to Get a Better Night’s Sleep for Centuries!

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Last week I sat down to watch a BBC documentary that focused on a theme that I’ve been quietly obsessing about for the last few months: sleep. Or more accurately – how to get a better night’s sleep. The programme followed the genial Dr Michael Mosley as he attempted to discover the ‘truth about sleep’ in a bid to overcome his own sleep problems. As Mosley dejectedly explained to the viewer, he suffered from insomnia and was ready to become a human lab rat in order to cure himself of the condition. Mosley talked to a variety of scientists and sleep experts that confirmed how detrimental sleep loss can be for a person’s health and well-being. Not only can it lead to irritability and loss of productivity, new studies are also showing that sleep deprivation could be an underlying cause of the obesity crisis and the explosion of people suffering from type 2 diabetes.[1]

Equipped with this worrying information, Mosley set out on a quest to discover what he described as ‘pioneering’ methods for improving our sleep. These ‘surprising’ and ‘unusual’ cures included practicing mindfulness before bed, taking a hot bath before settling down to sleep, eating two kiwi fruits an hour before bed, and taking a supplement of dietary prebiotics. Mosley recruited a further three sleep-deprived Britons to help him test out these innovative treatments. But as Dr Mosley and his group of plucky volunteers set out to put these apparently cutting edge approaches to sleep to the test I couldn’t help but feel that all this sounded remarkably familiar. Relaxing the mind before bed; ensuring a cool body temperature before sleep; regulating what you eat in the hours leading up to bedtime. These are not new ways of thinking about how to get a better night’s sleep. For centuries similar advice has been meted out. From early modern health regimens, to household recipe books, there is a plethora of evidence that suggests that the ‘pioneering’ methods identified by Mosley have actually been in use for centuries, begging the question: is the truth about sleep that we’ve just forgotten how to do it properly?

  1. Mindfulness and Relaxing the Mind

Mindfulness may seem like a very modern technique for dealing with the stresses of modern life. The OED defines mindfulness as ‘a mental state achieved by focusing one’s awareness on the present moment, while calmly acknowledging and accepting one’s feelings, thoughts, and bodily sensations’.[2] Whilst early modern people obviously did not use this specific therapeutic technique to help them nod off effectively, they did practice similar methods of relaxation before sleep. The medical advice of the period encouraged men and women to put aside their worldly concerns and anxieties and calm their passions at bedtime. As the sixteenth-century English physician William Bullein advised his readers in his health regimen The Government of Health, when sleep approached ‘beware of carefulnes for worldly thynges: looke not into the glasse of desperacion, with agonie and hevines of minde, hope ever for the beste’.[3] Bedtime prayer could also offer people a means by which to relax their minds before bed. By begging forgiveness for sins, asking for God’s protection, and reiterating their faith, early modern Christians relieved themselves of the day’s anxieties and prepared their bodies and souls for restful slumber. These devotional practices had a calming effect and helped alleviate the stresses of work and family life; bedtime prayer thus represented a combined source of spiritual, physical, and psychological comfort.[4] In turn these soothing effects ensured a peaceful and restorative night’s sleep.

  1. Regulating the Body’s Temperature

The theory behind having a warm bath before bed stems from the fact that sleep is brought on when our body temperature starts to decline. By having a warm bath, immediately followed by spending a couple of hours in a cooler environment, the process of cooling is stimulated, which in turn encourages the onset of sleep.[5] In Mosley’s documentary, fancy thermal imaging cameras are used to show this process in action. Yet despite the elaborate technology, the argument that being cool helps you sleep better has been made for centuries. In the early modern period, sleep was understood as a process in which the body’s extremities were cooled as the body’s heat was drawn inwards to the stomach to help digestion. A cool sleeping environment therefore naturally facilitated this process and regulated the body’s inner heat, which in turn stopped the body from over-heating and waking prematurely. The physician Andrew Boorde advised his readers therefore to lie in bed ‘not to hot nore colde, but in temporaunce’.[6] Instead of taking a warm bath to encourage this process, early modern people were advised to use thinner quilts in summer, open their windows to ventilate their bedchambers, and avoid lighting fires at night.

  1. Eating Foods Rich in Prebiotics and Serotonin

Of all the techniques trialled in the documentary, it was Dr Mosley’s use of a prebiotic supplement that looked most space-aged to me. Pouring a sachet of suspiciously non-descript white powder into his cup of tea, Mosley seemed convinced that it wouldn’t work. But like the other experiments undertaken in the programme, the use of prebiotics to combat poor sleep also seems to have a long and rich historical pedigree. Whilst Mosley used a concentrated powdered form of dietary prebiotics they can also be found in an array of foods that many of us consume regularly, such as onions, garlic, leeks, artichokes, and asparagus. In the early modern period onions in particular were considered an ingredient that helped provoke sleep. William Bullein explained to his readers that onions were known to ‘make thin the blood, and bring sleepe’. [7] This belief was corroborated by many other physicians. Writing in the early sixteenth century, Thomas Elyot claimed that onions ‘beynge eaten in great abundance with meate’ ‘cause one to  sleape soundely’.[8] The reason that prebiotic foods could potentially help us sleep better is down to the fact that they are believed to buffer the physiological impacts of stress. Stress and anxiety can lead to a reduction of healthy gut bacteria that helps the body regulate temperature. When this healthy bacteria is reduced, then, the onset of sleep can become inhibited. By eating foods rich in prebiotics  – which serve as food for this healthy gut bacteria – you could potentially reduce the impact of stressful events on your sleep.[9] Similar processes are at work with foods that have high levels of serotonin, such as kiwis (as seen in the documentary), tomatoes, and various types of nuts and seeds.[10] Serotonin boosting almonds, in particular, were used as a common cure for sleep loss in the early modern period.[11]




In the early modern period getting a good night’s sleep was considered crucial to both bodily health and spiritual well-being. People went to great lengths to make sure they slept well, developing a range of seemingly effective techniques that ensured this. Whilst knowing about the scientific and neurological basis of these potential sleep cures is undoubtedly important, a reliance on science alone will not solve the sleep crisis currently gripping our own society. If we want to improve our own sleep, we need to follow in the footsteps of our ancestors and place much more value on sleep and recognise how integral it is to our health and happiness.



[1] Jean-Phillipe Chaput, ‘Is Sleep Deprivation a Contributor to Obesity?’, World Obesity Federation, last accessed 16th May, 2017,

[2] ‘Mindfulness’, Oxford English Dictionary Online, last accessed 16th May, 2017,

[3] William Bullein, A Comfortable Regiment (London, 1562), sig. E3v.

[4] Sasha Handley, Sleep in Early Modern England (New Haven and London: Yale University Press, 2016) 88-89.

[5] Abigail Abrams, ‘How Showering at Night Helps You Sleep’, Time Magazine, last accessed 16th May, 2017,

[6] Andrew Boorde, A Compendyous Regyment or a Dyetary of Healthe (London, 1547), sig. C1v.

[7] William Bullein, The Government of Health (London, 1595), fol. 44.

[8] Thomas Elyot, The Castel of Helth (London, 1539), fols. 26-27.

[9] Lisa Marshall, ‘Dietary Prebiotics Improve Stress’, University of Colorado, last accessed 17th May, 2017,

[10] Ryan Hurd, ‘How Does Serotonin Affect Sleep?’, Live Strong, last accessed 17th May, 2017,

[11] Elyot, Castel of Helth, fol. 25.

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