Sleep may have effects on all systems of the body.
Many parts of the brain are involved in the processes of producing hormones and chemicals that regulate sleep and wakefulness.
In adults, a lack of sleep has been associated with a wide range of negative health consequences including weight harms, cardiovascular problems, a weakened immune system, and higher risk of obesity and type II diabetes.
Medical disorders which may contribute to sleep disturbances include Parkinson's disease, Alzheimer’s disease, chronic pain, poor bladder control, gastrointestinal conditions, neurological conditions, and respiratory conditions.
Other factors may contribute to poor sleep such as comorbid disorders, medications used to treat these disorders, lack of exercise, stress, pain, poor sleep habits, circadian rhythm disturbances, insomnia, or other chief sleep disorders.
Primary or chief sleep disorders include sleeplessness, restless leg syndrome, sleep apnea, periodic sleep disorder, disrupted sleep-wake cycle, behavior confusions, and insomnia.