It turns out that too much shut-eye, as well as too little, could be linked to health problems.
People older than 65 who sleep more than eight or nine hours a night may have twice the risk of developing Alzheimer's disease compared with those who get six to and eight hours, according to a new study reported by Britain's Telegraph.
Daily naps which push the sleep total higher than 8 hours may also have a negative effect.
Researchers believe that oversleeping could be an early sign of Alzheimer's or other types of dementia.
Estimates put the number of American cases of Alzheimer's between 3.1 million and more than 5 million, according to the Associated Press. Projections to the year 2050 estimate as many as 16 million could have the disease.
The study cited by the Telegraph was undertaken by the University Hospital in Madrid, Spain, and involved 3,286 volunteers age 65 or older. The men and women were then monitored for more than three years. They answered health and lifestyle questions, included the average amount of sleep, including naps, they had during a 24-hour period.
Of the original participants, 140 developed Alzheimer's or another type of dementia.
The biggest increase in risk was found among those people who slept more than eight or nine hours a day.
Quoted by the Telegraph in a report explaining their findings, the researchers said they "found a significant association between long sleep duration and dementia."
"Long sleep may be an early symptom of dementia, or could lead to an increased risk of it," the researchers continued. "But the mechanisms underlying this association are not readily available."
The head of research at the Alzheimer's Society, Dr. Susanne Sorenson, said that more research is needed to investigate the results of the study.
"There is no apparent physiological link, and it is unlikely that sleeping more than normal is a direct risk factor for dementia; it may simply be an early sign of a yet undiagnosed condition," she told The Telegraph.
She said that the study "demonstrates that sleeping longer than normal and feeling sleepy during the day is linked to getting dementia."
Quote: Can Sleepless Nights Lead to Alzheimer's Disease?
Those frequent sleepless nights nursing students and faculty frequently experience may be doing more than making us tired the following day. Researchers from Stanford and Washington University have recently determined that sleep deprivation and disturbed sleep cycles contribute to the development of amyloid-β (Aβ) in the extracellular fluid of the brain. This protein becomes the amyloid plaque we know as a hallmark for Alzheimer's disease.
Aβ is produced by neurons and deposited in the interstitial fluid of the brain (ISF), and converts to a damaging form as the concentration increases. Kang et al1 monitored changes in Aβ levels by inserting microdialysis probes in experimental mice. ISF Aβ levels were negatively correlated with the amount of time the mice slept and increased when the mice were awake. ISF Aβ levels were significantly higher during times of forced wakefulness. Following sleep deprivation the mice slept longer when allowed to do so and ISF Aβ levels decreased. Mice subjected to 20 hours of sleep deprivation for 21 days showed much higher levels of Aβ plaque deposition than their age-matched litter mate controls.
Sleep disturbances are known to be associated with various neurodegenerative diseases1 and now shown to be associated with the changes that contribute to Alzheimer's disease. Perhaps further understanding of the physiology of sleep and ways to optimize sleep could inhibit accumulation of Aβ plaque. This could thus slow the development and progression of Alzheimer's disease.
Meanwhile, remember that a good night's sleep is better for your health than you ever before imagined.
I'm 74+ and would be soooo happy to get 7 or 8 hrs of sleep at night. I have
no major health problems except Diabetes. On nights I get less than 6 1/2 hrs,
I usually take an afternoon nap around 2pm. A full night's sleep isn't easy to
get when one wakes up to tinkle every 4 to 5 hrs. If I'm lucky I sleep to 7am
or a bit later.
"The head of research at the Alzheimer's Society, Dr. Susanne Sorenson, said that more research is needed to investigate the results of the study.
"There is no apparent physiological link, and it is unlikely that sleeping more than normal is a direct risk factor for dementia; it may simply be an early sign of a yet undiagnosed condition," she told The Telegraph."
It's not something I'm going to loose sleep over! I believe that alzheimers is basically heavy metal poisoning,which, I would not doubt would tend to make one sleep more. Again, which comes first....?
I imagine that having AD might cause one to sleep more or less also, depending on their system and personality. Back in the day, when they said older people got dementia sometimes, and would be forgetful, etc., it didn't seem to be so bad. AD is a much worse, and I agree that metal toxicity like aluminum is something to be wary of.