Long naps linked to Alzheimer’s

Recent studies suggest a potential bidirectional relationship between daytime napping and Alzheimer’s disease, raising questions about whether excessive napping is merely a symptom or a contributing factor to cognitive decline. 

A 14-year study involving 1,401 older adults found that while napping generally increases with age, people with Alzheimer’s disease experienced a significantly greater increase in both the frequency and duration of daytime naps. They have more than double the yearly nap rate of their cognitively healthy peers. 

This increase in napping was also associated with worsened cognitive performance one year later, suggesting that excessive napping may not only reflect disease progression but also exacerbate it. 

Importantly, napping itself does not directly cause Alzheimer’s. However, research indicates that longer naps – particularly those of more than two hours – may elevate the risk of cognitive impairment, a known precursor to Alzheimer’s. 

A 2019 study of 2,751 older men revealed that those who napped for two hours or more daily had a 66% higher chance of developing cognitive issues over the following 12 years compared to those who napped for less than 30 minutes. 

Conversely, short naps may offer protective benefits. A 2021 study involving 389 older adults found that naps under 30 minutes were associated with a reduced risk of cognitive decline over five years. 

These findings suggest that nap duration plays a critical role in brain health, with brief naps potentially enhancing alertness and memory consolidation. 

The underlying mechanisms remain unclear, but researchers speculate that Alzheimer’s may disrupt wakefulness-promoting neurons in the brain, leading to increased daytime sleepiness. This disruption could create a feedback loop where excessive napping further impairs cognitive function. 

While napping is common among older adults, especially those experiencing sleep disturbances, excessive daytime sleepiness lasting more than two to three weeks should prompt medical evaluation. 

It may signal underlying conditions such as sleep disorders, medication side effects, or early signs of dementia. 

Experts recommend limiting naps to under 30 minutes and maintaining consistent sleep routines to support cognitive health. 

As research continues, understanding the nuances of sleep behaviour may offer valuable insights into Alzheimer’s prevention and management. 

Related reading: Medical News Today, Harvard Gazette