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
