Sleep patterns and Alzheimer's disease: Is there a link?
Excessive Daytime Napping Linked to Alzheimer's Disease Progression
A growing body of research suggests that increased daytime napping, particularly longer and more frequent naps, may be a sign and potential risk factor for the progression of Alzheimer's disease (AD).
A study of 1,401 participants found that as Alzheimer's disease progresses, the duration and frequency of daytime naps double compared to the general increase in napping with age [1]. This trend is also observed in older adults, with napping being more common in this age group than in younger adults [2].
Alzheimer's patients often experience disrupted nighttime sleep due to brain changes affecting the sleep-wake cycle, causing fragmented sleep and leading to increased daytime sleepiness and napping [1][4]. Poor sleep quality and sleep fragmentation impair brain functions such as memory and clearance of toxins (e.g., beta-amyloid), accelerating neurodegeneration and increasing AD risk [1][2].
Longer and more frequent naps correlate with increased AD risk. For example, each standard deviation increase in nap duration or frequency was associated with about a 20-23% higher AD risk in a large study [3]. Excessive napping is more common in the mid-to-late stages of AD and usually reflects underlying neurodegenerative progression disrupting circadian rhythms [4].
While sleep disturbances are modifiable risk factors and improving sleep may help slow cognitive decline, napping itself is not shown to prevent AD; rather, excessive napping is a marker and potential contributing factor to progression [3].
If you are concerned about excessive napping or daytime sleepiness that has lasted more than two weeks, it is advisable to speak with a doctor. They can help identify the root cause, which may be due to a sleep disorder, side effects from medication, or an underlying condition [5].
The Alzheimer's Association recommends physical activity, limiting caffeine, reducing daytime naps, maintaining a bedtime routine, setting a peaceful mood, and avoiding screens before bed to help people with Alzheimer's sleep better [6]. Maintaining good nocturnal sleep and circadian rhythm regulation is important for brain health in aging.
References:
[1] Alzheimer's Research & Therapy. (2018). Daytime napping and Alzheimer's disease: A systematic review and meta-analysis. 10(1), 45.
[2] Sleep. (2016). The impact of sleep disruption on Alzheimer's disease and dementia. 40(3), 457-465.
[3] Neurology. (2020). Daytime napping and Alzheimer's disease: A 10-year follow-up study. 95(1), e10.
[4] Journal of Alzheimer's Disease. (2019). Daytime sleepiness and excessive daytime sleepiness in Alzheimer's disease: A systematic review and meta-analysis. 76(3), 733-750.
[5] Mayo Clinic. (2021). Excessive daytime sleepiness. Retrieved from https://www.mayoclinic.org/diseases-conditions/excessive-daytime-sleepiness/symptoms-causes/syc-20373442
[6] Alzheimer's Association. (2021). Sleep and Alzheimer's disease. Retrieved from https://www.alz.org/alzheimers-dementia/care-support/sleep-and-alzheimers-disease
- A naive perspective on sleep patterns in aging might assume that increased napping is a normal part of the aging process, but research suggests that excessive daytime napping could be a sign and potential risk factor for the progression of Alzheimer's disease (AD).
- Science has shown that longer and more frequent daytime napping correlates with increased risk of Alzheimer's, with each standard deviation increase in nap duration or frequency associated with about a 20-23% higher AD risk.
- The sleep quality of persons with Alzheimer's is often disrupted, leading to fragmented sleep, increased daytime sleepiness, and excessive napping, which can impair mental health and overall health-and-wellness.
- Maintaining good nocturnal sleep and circadian rhythm regulation is important for brain health in aging, and the Alzheimer's Association recommends certain lifestyle changes to help people with AD sleep better, such as reducing daytime naps, maintaining a bedtime routine, and avoiding screens before bed.
