Chronic illness or pain can cause insomnia. Urinary incontinence or frequency, caused by drugs, prostate enlargement, or loss of bladder control, can interrupt sleep. Chronic lung diseases can cause frequent arousal due to decreased oxygen and the feeling of air hunger. Arthritis causes joint pain and stiffness, making it hard to sleep. Alzheimer's patients have decreased total sleep time and more frequent awakenings.
Sleep apnea is a disorder where breathing stops periodically throughout the night.
Most cases are due to partial airway blockage, and obesity is a contributing factor. Loud snoring and a characteristic arousal snort are signs of sleep apnea. Periodic movements in sleep is a condition where there is powerful flexing of the lower leg muscles many times throughout the night. Restless leg syndrome is a creepy, crawly, uncomfortable sensation in the leg muscles throughout the night. It can make falling asleep and staying asleep hard.