Two main models exists as to the mechanism of insomnia, cognitive and physiological. The cognitive model suggests rumination and hyperarousal contribute to preventing a person from falling asleep and might lead to an episode of insomnia. The physiological model is based upon three major findings in people with insomnia; firstly, increased urinary cortisol and catecholamines have been found suggesting increased activity of the HPA axis and arousal; second, increased global cerebral glucose utilization during wakefulness and NREM sleep in people with insomnia; and lastly, increased full body metabolism and heart rate in those with insomnia. All these findings taken together suggest a dysregulation of the arousal system, cognitive system, and HPA axis all contributing to insomnia. However, it is unknown if the hyperarousal is a result of, or cause of insomnia. Altered levels of the inhibitory neurotransmitter GABA have been found, but the results have been inconsistent, and the implications of altered levels of such a ubiquitous neurotransmitter are unknown. Studies on whether insomnia is driven by circadian control over sleep or a wake dependent process have shown inconsistent results, but some literature suggests a dysregulation of the circadian rhythm based on core temperature. Increased beta activity and decreased delta wave activity has been observed on electroencephalograms; however, the implication of this is unknown. Around half of post-menopausal women experience sleep disturbances, and generally sleep disturbance is about twice as common in women as men; this appears to be due in part, but not completely, to changes in hormone levels, especially in and post-menopause. Changes in sex hormones in both men and women as they age may account in part for increased prevalence of sleep disorders in older people.
symptom of Gigantism
symptom of Gastritis
symptom of Peptic ulcer disease
symptom of Short bowel syndrome
symptom of Gastroenteritis
symptom of Volvulus
symptom of Stomach cancer
symptom of Gastroesophageal reflux disease