The Health Risks of Oversleeping

By Marzia KhanReviewed by Danielle Ellis, B.Sc.

Health risks associated with oversleeping
Cognitive impairment
Oversleeping and cognitive decline
Mental health and depression
Cardiovascular risks
Metabolic disorders and obesity
Inflammation linked to oversleeping
The U-shaped sleep phenomenon
Practical recommendations for healthy sleep
References
Further reading

Oversleeping, also known as hypersomnia, generally includes those sleeping nine or more hours per night for more than a couple of weeks and still waking up feeling fatigued.¹

A sleep specialist, Michelle Drerup, PsyD, DBSM, states, “A common experience with oversleeping is that the more you sleep, the worse you feel.”¹

Signs of oversleeping may include (i) sleeping through your alarm, (ii) waking up with the alarm before turning it off and going back to sleep, (iii) waking up but not being able to get out of bed, (iv) waking up most days with a headache; (v) always feeling sleepy no matter how much you sleep, and (vi) never feeling refreshed.¹

Routine oversleeping may be a symptom of an underlying disorder, and if these symptoms persist for more than six to eight weeks, it may be a sign to seek help from a healthcare provider.¹

Health risks associated with oversleeping

With sleep having a critical role in several somatic, cognitive, and psychological processes, it is essential for overall health and survival.²

Health risks of sleeping too much include associations with obesity, diabetes, hypertension, and cardiovascular diseases, with a 20-30% higher mortality risk being reported. The evidence for a higher mortality rate for oversleeping may even be more substantial than its association with less sleep.²

Cognitive impairment

While less sleep is known to have associations with impaired cognition, relating predominantly to memory and an increased risk of Alzheimer's disease, there is also a link between oversleeping and cognitive function, particularly in decision-making.³

Oversleeping and cognitive decline

A cross-sectional study published by JAMA Neurology reported participants that who had a long sleep duration of nine hours or longer had significantly worse performance on the Digit Symbol Substitution Test (DSST) than those with normal sleep duration.⁴

Long sleep duration was also associated with worse self-reported cognitive function on the participant-as-assessed Cognitive Function Index (CFI).⁴

The risk of developing a cognitive disorder is also significantly raised when sleep duration is longer than 10 hours, with increased duration significantly elevating the risk of cognitive disorders in non-demented elderly.⁵

Mental health and depression

The authors of the cross-sectional neurology study also found participants in the longer sleep duration group reported more depressive symptoms compared to the normal sleep duration group.⁴

Additionally, 15% of those with depression have also experienced oversleeping, with major depressive disorder leading to persistent sadness, loss of interest in activities that were previously enjoyed, as well as disrupted thinking, memory, eating, and sleeping.¹

Those with this depressive disorder may feel like sleep is a form of escapism and may aid in avoiding facing the hardships of life. However, while depression can cause oversleeping, oversleeping can also increase depression.¹

A survey of a National Representative Sample of 24,671 adults found that oversleeping longer than 10 hours a day had a higher likelihood of having psychiatric diseases.²

Oversleeping participants were also reported to have slightly more psychological distress, as well as having experienced violent traumatic events before the age of 18 years.²

Cardiovascular risks

Increased cardiovascular disease has also been associated with oversleeping.⁴

An article published by the American Heart Association in Circulation, noted that oversleeping increases the risk of cardiovascular events and death in individuals with coronary artery disease.⁶

Dr Arshed Quyymi, director of the Emory Clinical Cardiovascular Research Institute, reported, “[There is] almost a 40 to 50% increased risk of dying if you are sleeping too little or too much.”⁶

Metabolic disorders and obesity

Increased BMI levels have also been associated with oversleeping, with higher BMI in midlife being correlated with late-life dementia.⁴

The National Representative Sample survey reported participants with longer sleep being more significantly overweight (BMI>25) as well as obese (BMI>30) compared with those with normal sleep durations.²

Additionally, the U.S. National Health Survey, which analyzed 56,507 participants, reported an association between long sleep of more than eight hours total sleeping time and health risks such as obesity, diabetes, hypertension, and cardiovascular issues.²

However, interestingly, there is a lack of consistent evidence that obesity is associated with oversleeping.²

Inflammation linked to oversleeping

An increase in habitual sleep duration is also correlated with an increase in pro-inflammatory cytokine levels, such as C-reactive protein (CRP) and interleukin-6 (IL-6) levels.⁷

IL-6 consists of a primary stimulus for CRP production by the liver, which may indicate that the association of sleep duration and CRP may be a secondary occurrence to the impact of sleep on IL-6.⁷

Increases in both CRP and IL-6 levels have been correlated with predicting an increased risk of having adverse health effects, including having a heart attack and diabetes.⁷

A study found that for every additional hour in sleep duration in long sleep durations, CRP levels increased by 8%, while IL-6 levels increased by 7%, with adjustments made for different variables.⁷

The U-shaped sleep phenomenon

The JAMA Neurology study reinforced previous research on the inverted U-shaped associations between self-reported sleep duration and cognition in aging, with both extreme sleep durations being correlated with worse cognitive performance.⁴

A meta-analysis on this topic also reported consistency in the research on the U-shaped association; however, associations with specific cognitive areas were found to be inconsistent.⁴

Some controversy has been found on whether extreme sleep durations impact some cognitive areas more than other areas and if short and long sleep durations correlate with distinctive patterns of dysfunctional cognition.⁴

In a different study, a U-shaped relationship was also shown for the association between dementia and sleep duration.⁵

Practical recommendations for healthy sleep

Maintaining balanced sleep habits is significant for overall health.¹

If you are experiencing signs of oversleeping, it may be useful to consult a healthcare provider or sleep specialist, as routine oversleeping is a symptom of an underlying disorder. Deciphering this underlying cause may be a significant step in receiving effective treatment.¹

Other actionable recommendations that can be used to manage symptoms at home can include establishing a consistent waking up time and placing your alarm clock on the other side of the room to encourage you to stay on your feet after turning your alarm off.¹

Additionally, finding a reason to get up, such as an appointment or a breakfast plan with a friend, may increase motivation to wake up earlier. Brushing your teeth and washing your face as soon as you wake up can work to decrease sleepiness.¹

Making going back to bed more of a challenge is also a good strategy, such as making your bed as soon as you wake up, engaging in physical activity, or going for a morning walk. Drinking coffee, health permitting may also be helpful for those who are struggling to start their day.¹

These strategies, along with appropriate medical treatment for a potential underlying disorder, maybe a significant approach in reducing oversleeping as well as the health risks of sleeping too much.¹

References

1. Do You Oversleep? https://health.clevelandclinic.org/oversleeping. Cleveland Clinic. Published July 8, 2024. Accessed January 6, 2025.
2. Léger D, Beck F, Richard J-B, Sauvet F, Faraut B. The Risks of Sleeping “Too Much”. Survey of a National Representative Sample of 24671 Adults (INPES Health Barometer). PLoS ONE. 2014;9(9). https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0106950 doi:10.1371/journal.pone.0106950.
3. Godman H. How Much Sleep Keeps Cognitive Decline at Bay? Harvard Health. https://www.health.harvard.edu/mind-and-mood/how-much-sleep-keeps-cognitive-decline-at-bay#:~:text=Sleeping%20six%20hours%20or%20less%20is%20associated%20with,linked%20to%20cognitive%20problems%2C%20especially%20in%20decision%20making. Published December 1, 2021. Accessed January 6, 2025.
4. Winer JR, Deters KD, Kennedy G, et al. Association of Short and Long Sleep Duration with Amyloid-Β Burden and Cognition in Aging. JAMA Neurology. 2021;78(10):1187. doi:10.1001/jamaneurol.2021.2876. https://jamanetwork.com/journals/jamaneurology/fullarticle/2783664
5. Xu W, Tan C-C, Zou J-J, Cao X-P, Tan L. Sleep Problems and Risk of All-Cause Cognitive Decline or Dementia: An Updated Systematic Review and Meta-Analysis. Journal of Neurology, Neurosurgery & Psychiatry. 2019;91(3):236-244. doi:10.1136/jnnp-2019-321896. https://jnnp.bmj.com/content/91/3/236
6. Kuehn BM. Sleep Duration Linked to Cardiovascular Disease. Circulation. 2019;139(21):2483-2484. doi:10.1161/circulationaha.119.041278. https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.119.041278
7. Patel SR, Zhu X, Storfer-Isser A, et al. Sleep Duration and Biomarkers of Inflammation. Sleep. 2009;32(2):200-204. doi:10.1093/sleep/32.2.200. https://pmc.ncbi.nlm.nih.gov/articles/PMC2635584/

Further Reading

• All Sleep Content
• What is Sleep?
• Types of Sleep Disorders
• How Can Mindfulness Meditation Improve Sleep?
• Promoting Sounder Sleep in Older Adults