Nocturia (nighttime urination) is so prevalent in sleep apnea patients that it has become a screening tool as significant as snoring. A research study showed that over 84% of patients with sleep apnea reported frequent nighttime urination while 82% acknowledged snoring.
Doctors know that nocturia is a sign of sleep apnea. However, people with nocturia are more likely to report the problem to their gynecologist or urologist, not a sleep clinician. Doctors most often attribute nocturia to aging in women or to prostate problems in men.
The question then arises…How many bathroom trips do you make during the night? It’s considered normal to wake up once or twice during the night to urinate, but many patients with untreated sleep apnea report as many as 6 or more nightly trips. Often, people assume that having a small bladder causes treks to the bathroom.
Nocturia is defined as awakening from sleep to voluntarily urinate. It differs from enuresis or bed-wetting, typically seen in children, where the child does not arouse from sleep, but the bladder empties anyway. Until recently, nocturia was thought to be caused by a full bladder, but it is also a symptom of obstructive sleep apnea. Some researchers believe that one event per night is within normal limits; two or more events per night may be associated with sleep deprivation.
How does apnea cause nocturia? During episodes of sleep apnea, the soft structures in the throat relax and close off the airway, setting into motion a chain of physiological events. Oxygen decreases, carbon dioxide increases, the blood become more acidic, the heart rate drops and blood vessels in the lung constrict. The body is alerted that something is wrong. The person must awaken enough to reopen their airway. By this time, the heart is racing and experiences a false signal of fluid overload. The heart then releases a hormone-like protein that tells the body to get rid of fluid resulting in nocturia.
The good news is that many people who have nocturia due to their untreated sleep apnea find that it resolves once their sleep apnea is addressed. We are aware that sleep apnea can and does cause a higher risk of heart problems and stroke. Nocturia is yet another motivation to become therapy compliant to achieve quality and restorative sleep.
Bed-wetting can also be caused by sleep apnea. Since breathing while asleep can be difficult for those with sleep apnea, the brain has to work harder to take in oxygen than it does to control other bodily functions, like bladder control.
In children, snoring and sleep apnea can be due to enlarged tonsils and adenoids that may be blocking the airway. If so, removing enlarged tonsils and adenoids to improve breathing often improves or eliminates bed-wetting.
Making sure we are evaluating quality of sleep while seeking answers to many such conditions is the key to ensuring good health for our children and our families.