A frequent need to get up and go to the bathroom to urinate at night is called nocturia. It differs from enuresis, or bedwetting, in which the person does not arouse from sleep, but the bladder empties anyway. Nocturia is a common cause of sleep loss, especially among older adults.
Most people without nocturia can sleep for 6 to 8 hours without having to urinate. Some researchers believe that one event per night is within normal limits; two or more events per night may be associated with daytime tiredness. Patients with severe nocturia may get up five or six times during the night to go to the bathroom.
Nocturia is often a symptom of other medical conditions including urological infection, a tumor of the bladder or prostate, a condition called bladder prolapse, or disorders affecting sphincter control. It is also common in people with heart failure, liver failure, poorly controlled diabetes mellitus, or diabetes insipidus. Diabetes, pregnancy and diuretic medications are also associated with nocturia.
Until recently, nocturia was thought to be caused by a full bladder, but it is also a symptom of sleep apnea.
Nocturia becomes more common as we age. As we get older, our bodies produce less of an anti-diuretic hormone that enables us to retain fluid. With decreased concentrations of this hormone, we produce more urine at night. Another reason for nocturia among the elderly is that the bladder tends to lose holding capacity as we age. Finally, older people are more likely to suffer from medical problems that may have an effect on the bladder.
In fact, nearly two-thirds (65%) of those responding to NSF's 2003 Sleep in America poll of adults between the ages of 55 and 84 reported this disturbance at least a few nights per week.