Interestingly, it has been shown that the sleep-wake cycle acts on the beta-amyloid burden which is a central component found in AD.[29][30] Indeed, during waking, the production of beta-amyloid protein will be more consistent than during sleep.[29][30][32] This is explained by two phenomena. The first is that the metabolic activity will be higher during waking and thus will secrete more beta-amyloid protein.[29][30] The second is that oxidative stress will also be higher and lead to increased AB production.[29][30]

This clock is a small part of the brain called the suprachiasmatic nucleus of the hypothalamus. It sits just above the nerves leaving the back of our eyes. Light and exercise "reset" the clock and can move it forward or backward. Abnormalities related to this clock are called circadian rhythm disorders ("circa" means "about," and "dies" means "day").

Narcolepsy is a brain disorder that causes excessive daytime sleepiness. There is sometimes a genetic component, but most patients have no family history of the problem. Though dramatic and uncontrolled "sleep attacks" have been the best-known feature of narcolepsy, in reality many patients do not have sleep attacks. Instead, they experience constant sleepiness during the day.
Although the exact mechanisms and the causal relationship between sleep disturbances and AD are not yet clear, these findings already provide a better understanding. In addition, they open up ideas for the implementation of treatments to curb the cognitive decline of patients suffering from this disease. In the same way, it also makes it possible to better target at risk population.
The most common sleep disorder is insomnia.[2] Others are sleep apnea, narcolepsy and hypersomnia (excessive sleepiness at inappropriate times), sleeping sickness (disruption of sleep cycle due to infection), sleepwalking, and night terrors. Management of sleep disturbances that are secondary to mental, medical, or substance abuse disorders should focus on the underlying conditions.
Sleep disturbances have been also observed in Alzheimer's disease (AD), affecting about 45% of its population.[22][24][26] Moreover, when it is based on caregiver reports this percentage is even higher, about 70%.[28] As well as in PD population, insomnia and hypersomnia are frequently recognized in AD patients, which have been associated with accumulation of Beta-amyloid, circadian rhythm sleep disorders (CRSD) and melatonin alteration.[22][24][28] Additionally, changes in sleep architecture are observed in AD too.[22][24][26] Even though with ageing the sleep architecture seems to change naturally, in AD patients it is aggravated. SWS is potentially decreased (sometimes totally absent), spindles and the time spent in REM sleep are also reduced, while its latency is increased.[28] The poorly sleep onset in AD has been also associated with dream-related hallucination, increased restlessness, wandering and agitation, that seem to be related with sundowning - a typical chronological phenomenon presented in the disease.[24][28]
What to do: Talk to experts about sleeplessness, and you'll be told to practice good "sleep hygiene." What this means is that you need to take your lack of sleep seriously and look at your sleep habits and physical surroundings to see what might be preventing you from sleeping well. Start with your evening habits: What do you do in the hours before bed? Eliminate late-night eating, drinking, and computer use and your chances of falling asleep quickly and sleeping soundly are much greater. Use the last hour before bed to do things that relax you, like taking a warm bath, meditating, or reading.
Interestingly, it has been shown that the sleep-wake cycle acts on the beta-amyloid burden which is a central component found in AD.[29][30] Indeed, during waking, the production of beta-amyloid protein will be more consistent than during sleep.[29][30][32] This is explained by two phenomena. The first is that the metabolic activity will be higher during waking and thus will secrete more beta-amyloid protein.[29][30] The second is that oxidative stress will also be higher and lead to increased AB production.[29][30]
The decrease in the quantity and quality of the NREM SWS as well as the disturbances of sleep will therefore increase the AB plaques.[29][30] This will first take place at the hippocampus level, from which memory is dependent.[29][30] This will result in cell death at this level and will contribute to diminished memory performances and cognitive decline found in AD disease.[29]

Sort of a milder cousin of sleep apnea, UARS occurs when some type of resistance slows or blocks air in the nasal passages. The most common causes are mild nasal congestion or a tongue position during sleep that blocks breathing. Because the resistance makes it harder work simply to breathe, your body is half-waking up over and over again during the night, so you don't feel refreshed in the morning.
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