Insufficient Sleep

The number one sleep problem worldwide is insufficient sleep–simply not getting enough sleep. How many people are not getting enough sleep varies across countries (see Table below), and the leading issue related to insufficient sleep is excessive daytime sleepiness (EDS). Across studies that took place in Asia, Australia, Korea, Japan, New Zealand, Poland, and Saudi Arabia, the prevalence of EDS both varies widely and ranges from 2.5-26%.¹

According to the National Institutes of Health,² one in three adults in the United States is not getting enough sleep, and the problem seems to be getting worse over time. For more than 35 years, the National Sleep Foundation has conducted an annual nationwide poll to ask adults living in their homes questions about their sleep. The table below shows the change over time in hours of sleep, including a historical reference from 1942. 

*Data are presented as %, except hours slept, which is mean number.

The 2024 poll found even more people experiencing short sleep duration, with almost two-thirds of US adults reporting not getting enough sleep, 57% of whom said that they would feel better if they could sleep longer. The problem is particularly severe among women, 64% of whom say that they don’t get the sleep that they need (compared with 52% of men).³

A recent study not only looked at the rate of short sleep duration (SSD, < 6 hours per 24 hours) in China, but also tied that information to years of life lost (YLL) and economic impact. They found that younger people and men were more likely to have SSD, with SSD rates increasing between 2010 and 2018. Taken together at a population level, the number of YLL to SSD increased from 66.75 million to 115.05 million YLLs over this timeframe. The associated economic cost reached $628.15 billion in 2018, 4.62% of the gross domestic product of China!⁴

A particularly concerning finding is the rate of insufficient sleep and poor sleep quality among medical students, which can affect patient care. A recent analysis of 109 studies that reported rates of sleep duration and problems among almost 60,000 medical students surveyed from around the world reported that 57% of medical students had poor sleep quality, with 33% experiencing excessive daytime sleepiness (EDS). The average amount of sleep was 6.5 hours, with more than 30% reporting getting less than the recommended 7-9 hours per night.⁵

Sleep Disorders

Let’s take a look at what researchers have found regarding the prevalence–how often people in a large population have a condition or symptom–of some common sleep disorders.  

Sleep problems affect millions upon millions of individuals throughout the world. When researchers looked at the results of 252 studies published from 1988-2023,⁶ representing data from 36 countries and almost 1 million older adults, they found that sleep problems, including insomnia, obstructive sleep apnea (OSA), excessive daytime sleepiness (EDS), sleep-related movement disorders, and circadian rhythm sleep-wake disorders (CRSWD) were extremely common, affecting 30-70% of adults. Having either insomnia or OSA was highly associated with having a number of issues, including frailty, dementia, poor quality of life, reduced cognitive performance, and mental health issues.

From Canever JB, Zurman G, Vogel F, et al. Worldwide prevalence of sleep problems in community-dwelling older adults: a systematic review and meta-analysis. Sleep Med. 2024;119:118-134.⁶

In the United States alone, more than 50-70 million people have been diagnosed with a sleep disorder, such as OSA, insomnia, restless legs syndrome (RLS), one of the central disorders of hypersomnolence (CDoH), or a CRSWD.²

Insomnia

According to a study by Morin and Jarrin,⁷ about 10% of adults experience insomnia, which is defined as difficulty falling asleep or difficulty staying asleep (or a combination thereof), and daytime effects (eg, fatigue; problems with concentration, attention, and memory; and irritability or a sense of unease). Another 20% of adults have occasional symptoms of insomnia. About 40% of people who have insomnia symptoms continue to have symptoms over a 5-year period–this is known as persistent insomnia.

Restless Legs Syndrome

Once thought to be a rare disorder, restless legs syndrome (RLS) is now known to affect about 10% of adults worldwide at least occasionally, with approximately 3% having symptoms severe enough to consider treatment.⁸ RLS is particularly common in pregnant women, people with end-stage kidney disease, and family members of people with RLS. More women than men have RLS.⁸ The age of onset of RLS has a bimodal distribution, meaning that there are 2 peaks in onset – one at approximately age 20 and another in the mid-40s.⁹

Obstructive Sleep Apnea

Based on an apnea-hypopnea index (AHI) of at least 5 events per hour, almost 1 billion adults worldwide aged 30–69 are estimated to have obstructive sleep apnea (OSA); 45% of these adults (ie, 425 million) have moderate to severe OSA (AHI ≥ 15).¹⁰

Circadian Rhythm Sleep-Wake Disorders

Surveys indicate that up to 3% of adults have a CRSWD, such as delayed or advanced sleep-wake phase disorder, shift work disorder, or jet lag; however,  researchers believe that up to 10% of adults and 16% of teenagers actually have an unrecognized CRSWD.¹¹ Although the sleep-wake disturbances caused by the most common CRSWD, jet lag, typically resolve over a short period of time, people with delayed or advanced sleep-wake phase disorder or shift work disorder may experience symptoms for years. 

Central Disorders of Hypersomnolence

The CDoH include narcolepsy 1 and 2 (with and without cataplexy, respectively) and idiopathic hypersomnia. In the United States, the prevalence of narcolepsy type 1 is estimated to be 12.6/100,000 people, and that of narcolepsy type 2 (narcolepsy without cataplexy) is 2.6/100,000.¹² Narcolepsy appears to be most prevalent in Japan (16/100,000) and least prevalent in Israel and Saudi Arabia (< 10/100,000).¹³ These numbers likely don’t represent the true prevalence, because narcolepsy is vastly unrecognized and undiagnosed.

Idiopathic hypersomnia (IH) is a rare disorder. The latest numbers indicate that, in the United States, 80,603, 89,539, and 92,139 people were diagnosed with IH in 2019, 2020, and 2021, respectively.¹⁴ This compares with a total of 4980 patients receiving a diagnosis of IH between 2014 and 2019,¹⁵ indicating that IH is being increasingly recognized and diagnosed.

References

1. Chattu VK, Manzar MD, Kumary S, Burman D, Spence DW, Pandi-Perumal SR. The global problem of insufficient sleep and its serious public health implications. Healthcare (Basel). 2018;7(1).
2. National Heart, Lung and Blood Institute. Sleep health. National Institutes of Health. https://www.nhlbi.nih.gov/health-topics/education-and-awareness/sleep-health. Accessed May 15, 2025.
3. Fioroni S, Foy D. Americans sleeping less, more stressed. Gallup. https://news.gallup.com/poll/642704/americans-sleeping-less-stressed.aspx. Published April 15, 2024. Accessed April 30, 2025.
4. Yan X, Han F, Wang H, Li Z, Kawachi I, Li X. Years of life lost due to insufficient sleep and associated economic burden in China from 2010-18. J Glob Health. 2024;14:04076.
5. Binjabr MA, Alalawi IS, Alzahrani RA, et al. The worldwide prevalence of sleep problems among medical students by problem, country, and COVID-19 status: a systematic review, meta-analysis, and meta-regression of 109 studies involving 59427 participants. Curr Sleep Med Rep. 2023:1-19.
6. Canever JB, Zurman G, Vogel F, et al. Worldwide prevalence of sleep problems in community-dwelling older adults: systematic review and meta-analysis. Sleep Med. 2024;119:118-134.
7. Morin CM, Jarrin DC. Epidemiology of insomnia: prevalence, course, risk factors, and public health burden. Sleep Med Clin. 2022;17(2):173-191.
8. Ohayon MM, O’Hara R, Vitiello MV. Epidemiology of restless legs syndrome: a synthesis of the literature. Sleep Med Rev. 2012;16(4):283-295.
9. Whittom S, Dauvilliers Y, Pennestri MH, et al. Age-at-onset in restless legs syndrome: a clinical and polysomnographic study. Sleep Med. 2007;9(1):54-59.
10. Benjafield AV, Ayas NT, Eastwood PR, et al. Estimation of the global prevalence and burden of obstructive sleep apnoea: a literature-based analysis. Lancet Respir Med. 2019;7(8):687-698.
11. Kim MJ, Lee JH, Duffy JF. Circadian rhythm sleep disorders. J Clin Outcomes Manag. 2013;20(11):513-529.
12. Ohayon MM, Duhoux S, Grieco J, Cote ML. Prevalence and incidence of narcolepsy symptoms in the US general population. Sleep Med. 2023;6:100095.
13. Wang Y, Chen Y, Tong Y, Li C, Li J, Wang X. Heterogeneity in estimates of incidence and prevalence of narcolepsy: a systematic review and meta-regression analysis. Neuroepidemiology. 2022;56(5):319-332.
14. Saad R, Black J, Bogan R, et al. Diagnosed prevalence of idiopathic hypersomnia among adults in the United States. Sleep. 2023;46:A369.
15. Saad R, Prince P, Taylor B, Ben-Joseph RH. Characteristics of adults newly diagnosed with idiopathic hypersomnia in the United States. Sleep Epidemiol. 2023;3.