Exploring Sleep Sayings: The Fascinating Origins of Common Sleep Idioms

Dec 22, 2023 | Blog

As a special holiday present to our readers, we are exploring the realm of sleep idioms and sayings, which are more than mere phrases. These expressions are cultural artifacts, providing a window into the lives and beliefs of our ancestors.

Join us in this festive journey through language and history!

“Sleep Tight”

The phrase “Sleep tight, don’t let the bedbugs bite” is a quaint, yet slightly eerie, way to say goodnight. A popular theory traces its origin to the tightness of bed ropes in old bedding systems. Before box springs, beds typically had a wooden frame with ropes supporting a mattress. For a comfortable sleep, it was crucial to tighten these ropes, hence the expression “sleep tight” (Bologna, 2021).

The phrase’s second part, “don’t let the bedbugs bite,” adds a humorous twist. Bedbugs were a common issue in the past, and this phrase humorously acknowledged the nightly struggle against them. It reminds us of a time when bedbugs were an unfortunate but regular part of life (Bologna, 2021).

“Catch Some Z’s”

To “catch some Z’s” is a playful way of saying it’s time to sleep, and its origin is visually driven. This phrase likely came from the cartoonish representation of snoring. In comic strips and cartoons, the letter “Z” is often used to symbolize the sound of sleep, perhaps because it visually resembles the rhythmic pattern of snoring (What does to catch some Z’s mean?).

The use of “Z” in this context is a perfect example of how visual culture influences language. The simplicity and universality of this representation have made it a staple in depicting sleep in popular media, thereby cementing the phrase in our everyday language.

“Out Like a Light”

“Out like a light” is an idiom that perfectly captures the experience of falling asleep quickly and deeply. The comparison to a light being turned off suggests an immediate transition from wakefulness to sleep, highlighting the abruptness of the action (N, 2023).

This saying may also reflect the advent of electricity and how it transformed our experience of night and day. The ability to instantly plunge a room into darkness with the flick of a switch is a relatively modern luxury, and this idiom encapsulates the magic of this technological advancement in the context of sleep.

“Beauty Sleep”

The concept of “beauty sleep” is rooted in the idea that sleep is essential for maintaining one’s appearance. This phrase is often used humorously, but it also carries a kernel of truth acknowledged by science and history alike. The rejuvenating effects of sleep on the body, including skin health and overall physical appearance, have been noted in various cultures (N, 2023).

Historically, the notion of beauty sleep has been referenced in literature and folklore, suggesting a long-standing belief in the restorative powers of sleep. This idiom not only reflects the value placed on physical appearance but also acknowledges the vital role of sleep in health and well-being (Axelsson et al., 2010).

“Hit the Hay” or “Hit the Sack”

“Hit the hay” and “hit the sack” are colloquial expressions that hark back to a time when mattresses or sleeping sacks were often filled with hay. These phrases evoke images of a rural, agricultural past where sleeping arrangements were far more rustic than today’s standards (Idiom origins).

These idioms also reflect a straightforward, no-nonsense approach to bedtime. The physical act of “hitting” the hay or sack suggests a direct and immediate approach to sleep, embodying a time when going to bed was perhaps a simpler and more straightforward affair.

“To Sleep on It”

The phrase “to sleep on it” suggests a thoughtful approach to decision-making. It implies that a good night’s sleep can provide clarity and perspective, a belief that is supported by modern research on sleep and cognitive function (Worley, 2018). Worley S. L. (2018). The Extraordinary Importance of Sleep: The Detrimental Effects of Inadequate Sleep on Health and Public Safety Drive an Explosion of Sleep Research. P & T : a peer-reviewed journal for formulary management, 43(12), 758–763.)

This idiom underscores the importance of rest in mental processes. It acknowledges that sleep is not just a physical necessity but also a crucial component of our cognitive and emotional well-being. By deferring decisions until after rest, this saying encapsulates the wisdom of considering our mental state in our decision-making processes.

These idioms offer a charming glimpse into the past, revealing how our ancestors viewed and valued sleep. They enrich our language and provide a unique lens through which to view historical and cultural attitudes towards rest and relaxation.

Learn More

If restful nights elude you, it might be time to seek expert guidance. Somnology’s comprehensive sleep services and data monitoring platform are engineered to provide everyone involved in the sleep care journey – from patients and care providers to healthcare payors and employers – with the information they need to improve health outcomes. With our innovative offerings like the SLaaS® (Sleep Lab as a Service) platform, we are revolutionizing the sleep care experience. We bring the sophistication of a sleep lab right to your fingertips, placing you, the patient, at the heart of everything we do. We are here to guide you every step of the way on your journey to better sleep. To discover more about how we can help you, visit our website.


  1. Axelsson, J., Sundelin, T., Ingre, M., Van Someren, E. J. W., Olsson, A., & Lekander, M. (2010, December 14). Beauty sleep: Experimental study on the perceived health and attractiveness of sleep deprived people. BMJ (Clinical research ed.). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3001961/
  2. Bologna, C. (2021, September 3). Here’s why people say “don’t let the bedbugs bite.” HuffPost. https://www.huffpost.com/entry/heres-why-people-say-dont-let-the-bedbugs-bite_n_5a5eb9e6e4b00a7f171b947c
  3. Idiom origins – hit the Hay/sack – history of hit the Hay/Sack. Origins of Idioms Archive. (n.d.). https://idiomorigins.org/origin/hit-the-haysack
  4. N, A. (2023, July 27). 22 sleeping idioms & expressions (with examples). Improving Your English. https://improving-your-english.com/vocabulary/idioms/sleeping-idioms/
  5. What does to catch some Z’s mean? Writing Explained. (n.d.). https://writingexplained.org/idiom-dictionary/catch-some-zs
  6. Worley S. L. (2018). The Extraordinary Importance of Sleep: The Detrimental Effects of Inadequate Sleep on Health and Public Safety Drive an Explosion of Sleep Research. P & T : a peer-reviewed journal for formulary management, 43(12), 758–763.