Fatigue during the first trimester of pregnancy is likely caused by changing levels of hormones, such as progesterone. Toward the end of pregnancy, some women find it difficult to sleep because of the uncomfortable size of their abdomen. Some women are too excited, anxious, or worried about becoming mothers to sleep well. Other women who are pregnant complain that vivid dreams prevent them from getting restful sleep. Sleep apnea, especially if it's severe and causes your blood oxygen level to drop during sleep, is a risk to the fetus.
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").

Waking up in the middle of the night to use the bathroom is such a common problem it has a name: nocturia . As we get older, our bodies' ability to hold fluids for long periods decreases, thanks to a decline in antidiuretic hormones. According to the National Sleep Foundation, 65 percent of older adults have sleep deprivation resulting from waking up frequently to use the bathroom.
As suggested by its name, PLMD is an involuntary movement disorder. (An older name, nocturnal myoclonus , is rarely used anymore.) People with this problem experience sudden, involuntary leg movements during the night, such as kicking or jerking. The difference between this and restless leg syndrome is that, unless the kicking wakes you up, you don't know you're doing it. You don't experience the tingling and discomfort that leads you to consciously move your legs, as with restless leg syndrome. At least 80 percent of people with restless leg syndrome have PLMD, but the reverse isn't true.
According to one meta-analysis, the two most prevalent sleep disorders among children are confusional arousals and sleep walking.[57] An estimated 17.3% of kids between 3 and 13 years old experience confusional arousals.[57] About 17% of children sleep walk, with the disorder being more common among boys than girls.[57] The peak ages of sleep walking are from 8 to 12 years old.[57] A different systematic review offers a high range of prevalence rates of sleep bruxism for children. Between 15.29 and 38.6% of preschoolers grind their teeth at least one night a week. All but one of the included studies reports decreasing bruxist prevalence as age increased as well as a higher prevalence among boys than girls.[58]
Although more research should be done to increase the reliability of this method of treatment, research suggests that music therapy can improve sleep quality in acute and chronic sleep disorders. In one particular study, participants (18 years or older) who had experienced acute or chronic sleep disorders were put in a randomly controlled trial and their sleep efficiency (overall time asleep) was observed. In order to assess sleep quality, researchers used subjective measures (i.e. questionnaires) and objective measures (i.e. polysomnography). The results of the study suggest that music therapy did improve sleep quality in subjects with acute or chronic sleep disorders, however only when tested subjectively. Although these results are not fully conclusive and more research should be conducted, it still provides evidence that music therapy can be an effective treatment for sleep disorders.[47]
In addressing sleep disorders and possible solutions, there is often a lot of buzz surrounding melatonin. Research suggests that melatonin is useful in helping people to fall asleep faster (decreased sleep latency), to stay asleep longer, and to experience improved sleep quality. In order to test this, a study was conducted that compared subjects that had taken Melatonin to subjects that had taken a placebo pill in subjects with primary sleep disorders. Researchers assessed sleep onset latency, total minutes slept, and overall sleep quality in the Melatonin and placebo groups to note the differences. In the end, researchers found that melatonin decreased sleep onset latency, increased total sleep time, and improved quality of sleep significantly more than the placebo group.[49][50]
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.
Insomnias This type of sleep disorder involves the inability to fall asleep or stay asleep. MORE>>Hypersomnias Hypersomnias are a group of sleep disorders that causes a person to be excessively sleepy. People with a hypersomnia may fall asleep at times that are inconvenient or even dangerous, such as at work or while driving. MORE>>Sleep Related Breathing Disorders Sleep disorders that involve difficulty breathing during sleep are classified as sleep related breathing disorders. Obstructive sleep apnea is the most common disorder of this type, however there are a number of variations of sleep apnea. MORE>>Circadian Rhythm Sleep-Wake Disorders Conditions in which the sleep times are out of alignment. A patient with one of these disorders does not follow the normal sleep times at night. MORE>>Parasomnias Parasomnias are a group of sleep disorders that involve unwanted events or experiences that occur while you are falling asleep, sleeping or waking up. MORE>>Sleep Movement Disorders This classification of sleep disorders includes conditions that cause movement during or prior to sleep. These disorders can make it difficult to fall asleep or stay asleep, or to get restful sleep. MORE>>
^ Hirshkowitz, Max (2004). "Chapter 10, Neuropsychiatric Aspects of Sleep and Sleep Disorders (pp 315-340)" (Google Books preview includes entire chapter 10). In Stuart C. Yudofsky; Robert E. Hales (eds.). Essentials of neuropsychiatry and clinical neurosciences (4 ed.). Arlington, Virginia, USA: American Psychiatric Publishing. ISBN 978-1-58562-005-0. ...insomnia is a symptom. It is neither a disease nor a specific condition. (from p. 322)
Sleep dentistry (bruxism, snoring and sleep apnea), while not recognized as one of the nine dental specialties, qualifies for board-certification by the American Board of Dental Sleep Medicine (ABDSM). The resulting Diplomate status is recognized by the American Academy of Sleep Medicine (AASM), and these dentists are organized in the Academy of Dental Sleep Medicine (USA).[53] The qualified dentists collaborate with sleep physicians at accredited sleep centers and can provide oral appliance therapy and upper airway surgery to treat or manage sleep-related breathing disorders.[54]
Obstructive sleep apnea (OSA) affects around 4% of men and 2% of women in the United States.[63] 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.[64] Also, they tend to report experiencing depression and insomnia in conjunction with obstructive sleep apnea.[65] 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,[66] at similar rates (prevalence of 3.5% and 3.57%, respectively).[63]
According to one meta-analysis, the two most prevalent sleep disorders among children are confusional arousals and sleep walking.[57] An estimated 17.3% of kids between 3 and 13 years old experience confusional arousals.[57] About 17% of children sleep walk, with the disorder being more common among boys than girls.[57] The peak ages of sleep walking are from 8 to 12 years old.[57] A different systematic review offers a high range of prevalence rates of sleep bruxism for children. Between 15.29 and 38.6% of preschoolers grind their teeth at least one night a week. All but one of the included studies reports decreasing bruxist prevalence as age increased as well as a higher prevalence among boys than girls.[58]
One factors that could explain this change in sleep architecture is a change in circadian rhythm, which regulates sleep.[29] A disruption of the circadian rhythm would therefore generate sleep disturbances.[29] Some studies show that people with AD have a delayed circadian rhythm, whereas in normal aging we will find an advanced circadian rhythm.[29][31]
^ Jump up to: a b c Cao, Xiao-Lan; Wang, Shi-Bin; Zhong, Bao-Liang; Zhang, Ling; Ungvari, Gabor S.; Ng, Chee H.; Li, Lu; Chiu, Helen F. K.; Lok, Grace K. I. (2017-02-24). "The prevalence of insomnia in the general population in China: A meta-analysis". PLoS ONE. 12 (2): e0170772. doi:10.1371/journal.pone.0170772. ISSN 1932-6203. PMC 5325204. PMID 28234940.
Delayed sleep phase disorder (DSPD), inability to awaken and fall asleep at socially acceptable times but no problem with sleep maintenance, a disorder of circadian rhythms. Other such disorders are advanced sleep phase disorder (ASPD), non-24-hour sleep–wake disorder (non-24) in the sighted or in the blind, and irregular sleep wake rhythm, all much less common than DSPD, as well as the situational shift work sleep disorder.[4]
Interestingly, the glymphatic cleanrance occurs during the NREM sleep, and more specifically the NREM SWS sleep.[29][30][32] As seen previously, it is a sleep stage that decreases in normal aging.[30] So there is less glymphatic clearance and an increase in AB burden that will form the AB plaques.[32][29][30] Therefor, in AD sleep disturbances will amplify this phenomenon.
On the other hand, it is during sleep that beta-amyloid residues are degraded to prevent plaque formation.[29][30][32] It is the glymphatic system that is responsible for this and this phenomenon is called glymphatic clearance.[29][30][32] Thus, during wakefulness, the AB burden is greater because the metabolic activity and oxidative stress are higher and there is no degradation of the protein by the glymphatic clearance whereas during sleep, the burden will be smaller as there will be less metabolic activity and oxidative stress in addition to the glymphatic clearance that occurs at this time.[30][29]
^ Keckeis, Marietta; Lattova, Zuzana; Maurovich-Horvat, Eszter; Beitinger, Pierre A.; Birkmann, Steffen; Lauer, Christoph J.; Wetter, Thomas C.; Wilde-Frenz, Johanna; Pollmächer, Thomas (2010). Finkelstein, David (ed.). "Impaired Glucose Tolerance in Sleep Disorders". PLoS ONE. 5 (3): e9444. doi:10.1371/journal.pone.0009444. PMC 2830474. PMID 20209158.

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: If you suspect you have a circadian rhythm disorder, take steps to get your body onto a regular sleep schedule. Choose a bedtime and wake-up time that work for you, and follow the same routine each day, even on weekends. This can be tough for those who have to get up early during the week but like to stay up later on weekends, but do your best to craft a compromise between your work week and weekend habits. The important thing is to avoid the trap of sleeping from 10 p.m. to 6 a.m. during the week, then suddenly shifting to late nights and late mornings on the weekends. This will inevitably leave you with insomnia on Sunday night, which in turn sets you up to start the week exhausted on Monday morning.
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