Sleep and dementia seem to have a complicated relationship. They appear to be related, but it can be very difficult to determine whether the disease is causing the symptom or vice versa. It can be a mixture of both.
Some research suggests that while sleeping at least seven or eight hours a night may be associated with a lower risk of developing dementia, people over 65 who sleep longer – eight and a half hours or more – could face a higher risk. The other extreme (insomnia) is linked to a 40% higher risk of suffering from mild cognitive impairment, sometimes considered a precursor to diseases such as Alzheimer’s disease.
A brain primed for dementia might also have difficulty effectively eliminating waste during sleep, a paper suggests.
And now, research published in The Journal of Gerontology: Medical Sciences suggests that our napping habits may also be associated with a 48% higher risk of dementia.
Daytime napping appears to be associated with dementia
This study included 995 adults aged over 65 and participating in the American Medicare program.
The study began in 2010 and participants’ health was tracked over a decade.
The researchers also looked at their napping habits. And they grouped people’s sleep habits by:
- Frequency (how often participants doze off during the day),
- Intention (whether the people who took the nap intended to do so or if it happened accidentally), and
- Duration (how long the naps lasted).
After comparing these results, researchers found that frequent napers, who caught midday zzz’s almost every day, were 48 percent more likely to develop dementia than non-snoopers.
People who napped unintentionally, without really meaning to, had a 39% higher risk, and a nap of 30 minutes or less was associated with a 40% increased likelihood.
These results held even when the researchers excluded people who had been diagnosed with dementia within five years of starting the study — that is, people who might have different sleep patterns due to undiagnosed early-onset dementia. This could mean that the change in sleep could appear before clearer signs of dementia.
The paper concluded that “frequent, involuntary napping was associated with a higher risk of developing possible/probable incident dementia over 10 years.”
The relationship may still be a two-way street
Dr. Adam Spira, lead author of the paper and professor in the Department of Mental Health at the Bloomberg School, said: “More frequent naps may be a marker of changes in the brain, rather than a cause of brain changes leading to dementia.”
Additionally, this article only showed an association and not a cause. This does not prove that any nap definitely causes dementia.
This is not, however, about the link between daytime napping and diseases like Alzheimer’s. Professor Dr Rayaz Malik previously said: “Frequent napping during the day is also a notable behavior associated with certain illnesses, including dementia, and loss of interest in friends and family is a sign that may indicate dementia.”
And Dr Susan Mitchell, head of policy at Alzheimer’s Research UK, also said: “Unusual sleep patterns are common in people with dementia, but research suggests that changes in sleep may be apparent long before symptoms such as memory loss start to appear.”
Gn Health
