Sleep

Evidence-based information about sleep and sleep hygiene

Why Sleep Matters

Sleep deprivation significantly impairs cognitive function[1] – affecting memory, decision-making, and reaction time.

Adults need 7-9 hours per night. Children need even more sleep for healthy development[2]. Chronic sleep deprivation is linked to obesity, diabetes, cardiovascular disease, and mental health issues.

Blue Light and Screens

**The Evidence:** Blue light from electronic devices affects circadian rhythms and melatonin production[3][4].

Screen time before bed is associated with worse sleep quality[5][6].

Practical advice:

Sleep Hygiene Tips

A warm bath or shower before bed can help you fall asleep faster[7][8].

Temperature

A cooler environment promotes better sleep[9] – your body needs to drop its core temperature to initiate sleep.

Consistency

A regular sleep schedule is important for sleep quality[10] – going to bed and waking at the same time, even on weekends.

Caffeine

Caffeine negatively affects sleep quality[11] – its half-life means significant amounts remain in your system.

Common Myths

**Myth:** "You can catch up on sleep on weekends"

Reality: Weekend sleep-ins don't fully reverse the effects of weekday sleep debt[12] – they can also disrupt your circadian rhythm (social jet lag).

**Myth:** "Alcohol helps you sleep"

Reality: Alcohol disrupts sleep quality even if it helps you fall asleep[13][14] – it suppresses REM sleep and causes fragmented sleep in the second half of the night.

**Myth:** "Everyone needs 8 hours"

Reality: Sleep needs vary by individual due to genetic factors[15] – most adults need 7-9 hours, but some function well on less or need more.

References

  1. Various (2021). Sleep deprivation impairs cognitive performance. Scientific Reports. [DOI]
  2. Various (2015). Sleep Duration Schedule and Quality among Urban Chinese Children. PLOS ONE. [DOI]
  3. Various (2024). Impacts of Blue Light Exposure From Electronic Devices on Circadian Rhythm. Chronobiology in Medicine. [DOI]
  4. Grzelak A (2024). Managing Blue Light Exposure: Impacts on Sleep Quality and Circadian Health. Quality in Sport. [DOI]
  5. Various (2023). Effect of screen time use and digital technology on sleep pattern. Int J Community Med Public Health.
  6. Various (2022). Are smartphones and tablets influencing the quality of sleep?. Epidemiology Biostatistics Public Health.
  7. Various (2022). A review of Japanese-style bathing: its demerits and merits. Journal of Physiological Anthropology. [DOI]
  8. LJMU Research (2018). A shower before bedtime may improve sleep onset latency of youth soccer players. LJMU Repository.
  9. Okamoto-Mizuno K, Tsuzuki K, et al. (2018). High rebound mattress toppers facilitate core body temperature drop and sleep. PLOS ONE. [DOI]
  10. Various (2020). The impact of structured sleep schedules prior to an in-laboratory study. PLOS ONE. [DOI]
  11. Zunhammer M, et al. (2014). Sleep Quality during Exam Stress: The Role of Alcohol, Caffeine and Nicotine. PLOS ONE. [DOI]
  12. Olds T, et al. (2012). Total Sleep Time Severely Drops during Adolescence. PLOS ONE. [DOI]
  13. Zunhammer M, et al. (2014). Sleep Quality during Exam Stress: The Role of Alcohol, Caffeine and Nicotine. PLOS ONE. [DOI]
  14. Various (2024). Associations of substance use and positive coping behaviors with sleep. Frontiers in Sleep. [DOI]
  15. Jones SE, et al. (2016). Genome-Wide Association Analyses Identify Sleep Duration Genetic Variants. PLOS Genetics. [DOI]