The question of how long you can go without sleep remains a fascinating puzzle in the realm of human physiology. While the exact duration eludes us, what is evident is that even short periods of sleep deprivation can have severe consequences. In this article, we delve into the importance of sleep, recommended durations, and the profound impacts of sleep deprivation on both body and mind.
The world record for staying awake
According to Guinness World Records, Robert McDonald from California has held the record for the longest time awake since 1986. He went an eye-watering 18 days 21 hours and 40 minutes without sleeping!
Guinness World Records no longer monitor this record due to the scientific consensus about the importance of sleep. Previous record holders and McDonald himself reported some side-effects during their events: hallucinations, delusions, extremely short attention spans, difficulty keeping food down, weight loss and changes in analytical abilities, perception, motivation, memory, and motor control. Little is known about the long-term ramifications these record holders experienced, but the entry in the Guinness Book of Records 1974 for Roger Guy English (record holder from 1974-77, 12 days ) says: “He has suffered hallucinations since this very dangerous test.”
Needless to say, pushing the limits of your ability to stay awake is probably not a good idea!
Recommended sleep duration
Sleep requirements change throughout different life stages. A general consensus of the American Academy of Sleep Medicine and Sleep Research Society is that you should aim for no less than 7 hours of sleep a night for optimal health. Based on your age and lifestyle, the National Sleep Foundation have produced these ranges:
| Age Group | Recommended Sleep Duration |
|---|---|
| Newborns (0-3 months) | 14-17 hours per day, including naps |
| Infants (4-11 months) | 12-15 hours per day |
| Toddlers (1-2 years) | 11-14 hours per night |
| Preschoolers (3-5 years) | 10-13 hours per night |
| School-age children (6-13 years) | 9-11 hours per night |
| Teenagers (14-17 years) | 8-10 hours per night |
| Adults (18-64 years) | 7-9 hours per night |
| Seniors (65+ years) | 7-8 hours per night |
However, the importance of sleep goes beyond mere duration; it’s also about the quality of sleep and its vital role in maintaining overall health.
Sleep requirements may also differ between men and women due to biological and hormonal variations and some studies suggest that, on average, women tend to need slightly more sleep than men. This difference may only equate to around 11 minutes a day. However, despite there perhaps not being a marked difference in overall time requirements per day, over a lifetime women sleep more that men and biological sex can impact melatonin production, time spent in different sleep phases and risks of different sleep disorders.
Fluctuations throughout a woman’s menstrual cycle due to hormonal changes can impact sleep quality and patterns and women tend to report more fluctuations in sleep quality throughout the month than men. Some women may experience more difficulty sleeping during the luteal phase (the time between ovulation and the start of menstruation) due to increased progesterone levels, leading to potential disturbances like insomnia or fragmented sleep. Menopause may also have a big impact on sleep quality, duration and the risk of sleep disorders like sleep apnoea. Understanding and adapting to these changing sleep needs can help women maintain optimal health and wellbeing.
The impact of sleep deprivation
The repercussions of sleep deprivation extend far beyond feeling groggy the next day. A 2017 review found sleep disruption to be linked to a myriad of health issues, including depression, anxiety, impaired cognitive function, and increased risk of chronic diseases such as type 2 diabetes, cardiovascular disease, and even colorectal cancer.
An increasing number of studies, including a 2019 review, has found an association between sleep deprivation and the development of Alzheimer’s disease. During sleep, the brain undergoes crucial processes of waste removal and repair. For instance, the glymphatic system, discovered relatively recently, is a network of channels that clears away toxins and metabolic by-products from the brain. When sleep is disrupted, this clearance process is compromised, potentially leading to the accumulation of harmful substances in the brain.
Other ways that insufficient sleep can affect the body include…
Cognitive impairment and emotional instability
A research article with three meta-analyses in one explored the connection between sleep deprivation, cognitive function, impaired memory, attention, and decision-making abilities. It found that sleep deprivation can also lead to increased irritability, mood swings, and difficulty regulating emotions. These effects stem from disruptions in brain regions responsible for cognitive processing and emotional regulation, such as the prefrontal cortex and amygdala.
Metabolic disruption and weight gain
Acute and chronic sleep deprivation can disrupt hormonal balance, particularly affecting hormones involved in appetite regulation, such as leptin, ghrelin and adiponectin. As a result, sleep-deprived individuals often experience increased hunger and cravings for high-calorie foods, leading to weight gain and metabolic dysfunction. Sleep deficiency can also impair glucose metabolism and insulin sensitivity, increasing the risk of developing type 2 diabetes and obesity.
Immune system suppression and increased susceptibility to illness
Sleep plays a key role in supporting immune function, with sleep deprivation impairing various aspects of the immune response. Specifically, inadequate sleep has been linked to reduced antibody production, changes in immune cell function and an increase in the production of pro-inflammatory chemicals throughout the body as well as the brain. This shift of immune activity can compromise the body’s ability to fight off infections, leaving sleep-deprived individuals more susceptible to illnesses ranging from the common cold to more severe infections.
Low-grade inflammation, associated with insufficient sleep, has been implicated in the development of cancer and neurodegenerative diseases.
Increased risk of cardiovascular disease
Emerging research indicates a strong association between chronic sleep deprivation and an elevated risk of cardiovascular disease (CVD). Prolonged sleep deficiency is linked to adverse changes in blood pressure, heart rate, and inflammation levels, all of which are key contributors to the development of CVD. Moreover, sleep disturbances disrupt the body’s natural circadian rhythm, which is intricately linked to regulating cardiovascular function. Over time, this disruption can lead changes to the cells that line the blood vessels (the endothelium), increasing the likelihood of clots forming and reducing vasodilation– the ability for blood vessels to relax, allowing blood to flow more freely. Therefore, prioritising sleep duration and quality is essential for maintaining cardiovascular health and reducing the risk of CVD.
During the transition to daylight saving time in spring and back to standard time in autumn, research indicates a definite increase in the rate of certain adverse health events. For instance, a prospective study published in Open Heart found a 24% increase in the incidence of heart attacks on the Monday following the transition to daylight saving time in the spring, whereas, when the clocks are set back in autumn, there was a 21% decrease.
Other notable areas of concern are an increase in the number of traffic accidents and fatalities, along with a short-term increase in workplace injuries, and reduced self-reported alertness following the spring shift to daylight saving time.
This phenomenon underscores the intricate relationship between sleep, circadian rhythms, and various aspects of health. Crazy what just an hour more or less of sleep can do!
Impaired physical performance and increased risk of accidents
Sleep deprivation can significantly impair physical performance, coordination, and reaction times, akin to the effects of alcohol intoxication. Athletes and individuals engaged in physical activity or labour may experience reduced endurance, strength, and motor skills due to inadequate sleep. Sleep deficiency can compromise the brain’s ability to process sensory information and execute precise movements. Whether on the field, in the workplace, or behind the wheel, sleep-deprived individuals are at greater risk of accidents and errors, posing a threat to both themselves and others.
Negative impact on mental health
Sleep is closely intertwined with mental health, with deprivation exacerbating symptoms of anxiety, depression, and stress. Chronic sleep deficiency can disrupt the delicate balance of neurotransmitters in the brain, including serotonin and dopamine, which play key roles in regulating mood and emotional wellbeing. Inadequate sleep can also impair the brain’s ability to process and cope with emotional stimuli, leading to heightened emotions and reduced resilience to stressors. Over time, persistent sleep deprivation can contribute to the development or worsening of mental health disorders, significantly impacting one’s quality of life and overall psychological wellbeing.
One meta-analysis of 65 randomised controlled trials (the most robust form of scientific evidence) found that the better the sleep quality, the more mental health improves, indicating a direct link between sleep and mental wellbeing. Adequate sleep hygiene and seeking timely intervention for sleep-related concerns are therefore key steps in safeguarding mental health and promoting emotional resilience.
For evidence-based guidance on how to get a better night’s sleep, check our our articles: How to improve your circadian rhythm and 15 tips for better sleep.
Disruption of the gut microbiome
Recent studies have highlighted the surprisingly intricate connection between sleep and gut health, and the importance of adequate rest in maintaining a balanced gut microbiome. The gut microbiome refers to the diverse community of microorganisms, including bacteria, fungi, and viruses, that inhabit the gastrointestinal tract, particularly the large intestines.
Sleep deprivation has been associated with dysbiosis—a condition characterised by an imbalance in the composition and diversity of microbes in the gut. This dysregulation can trigger inflammation, compromise the immune function, and disrupt metabolic processes. Dysbiosis has also been linked to different gastrointestinal disorders such as irritable bowel syndrome (IBS), inflammatory bowel disease (IBD) and colorectal cancer. Furthermore, alterations in gut microbiota composition have been linked to systemic health issues, including obesity, diabetes, non-alcoholic fatty liver disease and autoimmune conditions.
This suggests that sufficient sleep is essential not only for overall health but also for nurturing a thriving gut ecosystem, supporting digestive function, and reducing the risk of gut-related (and systemic) ailments.
Deep sleep and its restorative powers
Deep sleep, also known as slow-wave sleep, plays a pivotal role in bodily repair and regeneration. During this phase, the body undergoes essential processes such as tissue repair, muscle growth, and immune system modulation. Emerging research suggests that deep sleep may even have neuroprotective effects, potentially mitigating the risk of neurological disorders such as Alzheimer’s disease.
For more info, check out our article on Unlocking the power of deep sleep: how much do you need?
If you experience severe sleep issues, wake up still feeling tired, find yourself unintentionally falling asleep during the day or suspect you have insomnia, it’s advisable to seek guidance from a healthcare provider or your GP. They can look at your sleep patterns, identify possible causes, and make personalised recommendations and treatment options.
While the exact limit of human endurance without sleep remains uncertain, the detrimental effects of sleep deprivation are abundantly clear. Prioritising sufficient, high-quality sleep benefits so many aspects of overall health and wellbeing.
To access our Sleep Insights and more, download the Evergreen Life app and kick start your wellness journey by answering your available questionnaires.
Join the community: Unlock more insights
Reviewed by:
Anna Keeble MA BA Head of Content and Wellbeing Expert
Dr Claire Marie Thomas MRCGP DFSRH DTMH DipNLP MBChB BMedSci Medical Expert
- Atwal, S. (2023). What’s the limit to how long a human can stay awake? And why we don’t monitor the record. [online] Guinness World Records. Available here.
- Barnes, C.M. and Wagner, D.T. (2009). Changing to daylight saving time cuts into sleep and increases workplace injuries. Journal of Applied Psychology, 94(5), pp.1305–1317. Available here.
- Briançon-Marjollet, A., Weiszenstein, M., Henri, M., Thomas, A., Godin-Ribuot, D. and Polak, J. (2015). The impact of sleep disorders on glucose metabolism: endocrine and molecular mechanisms. Diabetology & Metabolic Syndrome, 7(1). Available here.
- Burgard, S.A. and Ailshire, J.A. (2013). Gender and Time for Sleep among U.S. Adults. American Sociological Review, [online] 78(1), pp.51–69. Available here.
- Buttó, L.F. and Haller, D. (2016). Dysbiosis in intestinal inflammation: Cause or consequence. International Journal of Medical Microbiology, [online] 306(5), pp.302–309. Available here.
- Daviaux, Y., Mignardot, J.-B., Cornu, C. and Deschamps, T. (2014). Effects of total sleep deprivation on the perception of action capabilities. Experimental Brain Research, 232(7), pp.2243–2253. Available here.
- Garbarino, S., Lanteri, P., Bragazzi, N.L., Magnavita, N. and Scoditti, E. (2021). Role of sleep deprivation in immune-related disease risk and outcomes. Communications Biology, [online] 4(1). Available here.
- Ibarra-Coronado, E.G., Pantaleón-Martínez, A.M., Velazquéz-Moctezuma, J., Prospéro-García, O., Méndez-Díaz, M., Pérez-Tapia, M., Pavón, L. and Morales-Montor, J. (2015). The Bidirectional Relationship between Sleep and Immunity against Infections. [online] Journal of Immunology Research. Available here.
- Kohansieh, M. and Makaryus, A.N. (2015). Sleep Deficiency and Deprivation Leading to Cardiovascular Disease. International Journal of Hypertension, [online] 2015, pp.1–5. Available here.
- Krause, A.J., Simon, E.B., Mander, B.A., Greer, S.M., Saletin, J.M., Goldstein-Piekarski, A.N. and Walker, M.P. (2017). The sleep-deprived human brain. Nature Reviews Neuroscience, [online] 18(7), pp.404–418. Available here.
- Liu, H. and Chen, A. (2019). Roles of sleep deprivation in cardiovascular dysfunctions. Life Sciences, [online] 219, pp.231–237. Available here.
- Lok, R., Qian, J. and Chellappa, S.L. (2024). Sex differences in sleep, circadian rhythms, and metabolism: Implications for precision medicine. Sleep medicine reviews, 75, pp.101926–101926. Available here.
- Longordo, F., Kopp, C. and Lüthi, A. (2009). Consequences of sleep deprivation on neurotransmitter receptor expression and function. European Journal of Neuroscience, 29(9), pp.1810–1819. Available here.
- Lu, J., Ma, K.L. and Ruan, X.Z. (2019). Dysbiosis of Gut Microbiota Contributes to the Development of Diabetes Mellitus. Infectious Microbes and Diseases, 1(2), pp.43–48. Available here.
- Mehal, W.Z. (2013). The Gordian Knot of dysbiosis, obesity and NAFLD. Nature Reviews Gastroenterology & Hepatology, [online] 10(11), pp.637–644. Available here.
- Mirer, A.G., Young, T., Palta, M., Benca, R.M., Rasmuson, A. and Peppard, P.E. (2017). Sleep-disordered breathing and the menopausal transition among participants in the Sleep in Midlife Women Study. Menopause, 24(2), pp.157–162. Available here.
- Mousa, W.K., Chehadeh, F. and Husband, S. (2022). Microbial dysbiosis in the gut drives systemic autoimmune diseases. Frontiers in Immunology, 13. Available here.
- Nowakowski, S., Meers, J. and Heimbach, E. (2013). Sleep and Women’s Health. Sleep Medicine Research, 4(1), pp.1–22. Available here.
- Portaluppi, F., Tiseo, R., Smolensky, M.H., Hermida, R.C., Ayala, D.E. and Fabbian, F. (2012). Circadian rhythms and cardiovascular health. Sleep Medicine Reviews, 16(2), pp.151–166. Available here.
- Posner, D. and Gehrman, P.R. (2011). Sleep Hygiene. [online] ScienceDirect. Available here.
- Prats-Uribe, A., Tobías, A. and Prieto-Alhambra, D. (2018). Excess Risk of Fatal Road Traffic Accidents on the Day of Daylight Saving Time Change. Epidemiology, 29(5), pp.e44–e45. Available here.
- Principi, N., Cozzali, R., Farinelli, E., Brusaferro, A. and Esposito, S. (2018). Gut dysbiosis and irritable bowel syndrome: The potential role of probiotics. Journal of Infection, 76(2), pp.111–120. Available here.
- Sandhu, A., Seth, M. and Gurm, H.S. (2014). Daylight savings time and myocardial infarction. Open Heart, 1(1), p.e000019. Available here.
- Scott, A.J., Webb, T.L., Martyn-St James, M., Rowse, G. and Weich, S. (2021). Improving Sleep Quality Leads to Better Mental health: a meta-analysis of Randomised Controlled Trials. Sleep Medicine Reviews, [online] 60(60), p.101556. Available here.
- Sun, J., Fang, D., Wang, Z. and Liu, Y. (2023). Sleep Deprivation and Gut Microbiota Dysbiosis: Current Understandings and Implications. International Journal of Molecular Sciences, [online] 24(11), pp.9603–9603. Available here.
- Tempesta, D., Socci, V., De Gennaro, L. and Ferrara, M. (2018). Sleep and emotional processing. Sleep Medicine Reviews, 40, pp.183–195. Available here.
- van Egmond, L.T., Meth, E.M.S., Engström, J., Ilemosoglou, M., Keller, J.A., Vogel, H. and Benedict, C. (2022). Effects of acute sleep loss on leptin, ghrelin, and adiponectin in adults with healthy weight and obesity: A laboratory study. Obesity, 31(3). Available here.
- Watson, N.F., Badr, M.S., Belenky, G., Bliwise, D.L., Buxton, O.M., Buysse, D., Dinges, D.F., Gangwisch, J., Grandner, M.A., Kushida, C., Malhotra, R.K., Martin, J.L., Patel, S.R., Quan, S. and Tasali, E. (2015). Recommended Amount of Sleep for a Healthy Adult: A Joint Consensus Statement of the American Academy of Sleep Medicine and Sleep Research Society. Journal of Clinical Sleep Medicine, [online] 11(6). Available here.
- Williamson, A.M. and Feyer, A.M. (2000). Moderate sleep deprivation produces impairments in cognitive and motor performance equivalent to legally prescribed levels of alcohol intoxication. Occupational and environmental medicine, [online] 57(10), pp.649–55. Available here.
- Wu, H., Dunnett, S., Ho, Y.-S. and Chang, R.C.-C. (2019). The role of sleep deprivation and circadian rhythm disruption as risk factors of Alzheimer’s disease. Frontiers in Neuroendocrinology, 54, p.100764. Available here.
