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.
Due to rapidly increasing knowledge about sleep in the 20th century, including the discovery of REM sleep in the 1950s and circadian rhythm disorders in the 70s and 80s, the medical importance of sleep was recognized. The medical community began paying more attention than previously to primary sleep disorders, such as sleep apnea, as well as the role and quality of sleep in other conditions. By the 1970s in the US, clinics and laboratories devoted to the study of sleep and sleep disorders had been founded, and a need for standards arose.
Obstructive sleep apnea (OSA) affects around 4% of men and 2% of women in the United States. In general, this disorder is more prevalent among men. However, this difference tends to diminish with age. Women experience the highest risk for OSA during pregnancy. Also, they tend to report experiencing depression and insomnia in conjunction with obstructive sleep apnea. In a meta-analysis of the various Asian countries, India and China present the highest prevalence of the disorder. Specifically, about 13.7% of the Indian population and 7% of Hong-Kong's population is estimated to have OSA. The two groups experience daytime OSA symptoms such as difficulties concentrating, mood swings, or high blood pressure, at similar rates (prevalence of 3.5% and 3.57%, respectively).
Primary sleep disorders are most common in men and women over the age of 65. About half of the people claim to have some sleep problem at one point. It is most common in the elderly because of multiple factors. Factors include increased medication use, age-related changes in circadian rhythms, environmental and lifestyle changes  and pre diagnosed physiological problems and stress. The risk of developing sleep disorders in the elderly is especially increased for sleep disordered breathing, periodic limb movements, lestless legs syndrome, REM sleep behavior disorders, insomnia and circadian rhythm disturbances.
Interestingly, the glymphatic cleanrance occurs during the NREM sleep, and more specifically the NREM SWS sleep. As seen previously, it is a sleep stage that decreases in normal aging. So there is less glymphatic clearance and an increase in AB burden that will form the AB plaques. Therefor, in AD sleep disturbances will amplify this phenomenon.
A systematic review found that traumatic childhood experiences (such as family conflict or sexual trauma) significantly increases the risk for a number of sleep disorders in adulthood, including sleep apnea, narcolepsy, and insomnia. It is currently unclear whether or not moderate alcohol consumption increases the risk of obstructive sleep apnea.
What to do: See your dentist for an exam. Bite problems are often a cause of bruxism, and it's a good idea to check for damage to your teeth. It's likely she'll suggest lifestyle changes, such as cutting out alcohol before bed. If you chew gum, stop -- the habitual chewing action can make it more likely you'll grind your teeth at night. Wearing a dental guard or splint at night is usually the next step for bruxism. Your dentist will fit you with a device that prevents your jaw from clenching. Other treatments include Botox injections to the jaw muscle, and a biofeedback device called Grindcare.