By Brandon R. Peters, M.D.
Just like clockwork, it's time to get up and pee again. If it seems like the bane of getting a continuous night of sleep in middle age and beyond, it may not have to be. Learn a surprising reason why you may have to wake to urinate at night and how improvement can occur without seeing a urologist, but a sleep specialist instead.
It is considered abnormal if you wake more than once at night to urinate. Ideally, you wouldn't wake at all. These awakenings can disturb sleep and contribute to insomnia, especially when they occur frequently or towards morning. What causes frequent urination at night, a condition known as nocturia, and what can be done about it?
In both women and men, nightly awakenings to urinate appear to be associated with poor sleep, even when other factors such as pain and other medical conditions are taken into account. In fact, nocturia may be the single most common factor associated with poor sleep among the elderly (1).
Many people, including doctors, have the wrong idea about the cause of nocturia. Too often men of a certain age are told it is due to an enlarged prostate. Women might blame excessive fluid intake in the evening, a hyperactive bladder, loss of bladder control, or even menopause. Prescription medications are paraded out to mixed effect. Men may have painful procedures to reduce the prostate's constriction of the urethra. What if something else entirely is to blame?
With aging, there is another phenomenon that often becomes apparent in sleep: obstructive sleep apnea. In fact, the risk increases 10-fold in women at the time of menopause (2). This condition is characterized by repeated pauses in breathing that lead to awakenings, sleep fragmentation, drops in blood oxygen levels, and - nocturia (3). Sleep apnea is associated with other classic symptoms, including:
- Excessive daytime sleepiness
- Insomnia (Frequent nighttime awakenings)
- Witnessed pauses in breathing
- Gasping or choking in sleep
- Dry mouth at night
- Night sweats
- Teeth grinding (Bruxism)
- Morning headaches
- Concentration and memory problems
- Mood problems
If any of these other symptoms are present, it may be necessary to investigate sleep apnea as a potential cause of nocturia. As an aside, in an important pairing alcohol often causes people to wake to urinate more at night because it also contributes to both snoring and sleep apnea.
Many people say that they get up to urinate because they are awake, their bladder feels somewhat full, and they aren't sure that they'll get back to sleep unless they do. As discussed, sleep-disordered breathing may trigger these awakenings, yet why is the bladder full?
The body normally releases anti-diuretic hormone (ADH) in sleep to prevent needing to wake to urinate. It works to shut down the kidneys, preventing movement of fluids from the blood vessels to the bladder. The bladder is like a storage balloon, and there is no need to wake to empty it if the fluid isn't there to start. No matter how well or poorly the bladder may function, or whether an enlarged prostate obstructs or not, without urine filling the bladder from overactive kidneys, these other issues should not matter.
Research and clinical experience demonstrates that sleep apnea changes the release of ADH (4). More severe sleep apnea may lead to pulmonary hypertension and right-sided heart failure. The body responds to this strain by stopping the release of ADH, which causes more urine to be produced, filling the bladder and triggering awakenings to pee during sleep.
When sleep apnea is effectively treated, most often with the use of continuous positive airway pressure (CPAP), these effects are quickly reversed (5). CPAP delivers a constant flow of air through a face mask that keeps the airway open and prevents the associated changes. Both men and women wake less to pee at night. Sleep quality substantially improves as fragmented sleep is relieved.
CPAP doesn't treat the bladder. It doesn't shrink the prostate. It doesn't make you less thirsty or dry you out. It doesn't put you in a deep sleep so you can't wake to pee. It simply treats one of the most common and often overlooked causes of nighttime urination. In so doing, those trips to the bathroom abate and often are fully eliminated.
For those who are convinced that getting up to pee is because of how much fluid was consumed in the evening, your age, an enlarged prostate or a weak bladder, think again. If you have some of the other symptoms associated with sleep apnea, meet with your doctor and get the evaluation and treatment you need to once again sleep through the night.
1. Bilwise DL, Foley DJ, Vitiello MV, et al. Nocturia and disturbed sleep in the elderly. Sleep Med 2009;10:540-548.
2. Bixler EO et al. "Prevalence of sleep-disordered breathing in women: effects of gender." Am J Respir Crit Care Med 2001;163:608-613.
3. Endeshaw YW, Johnson TM, Kutner MH, et al. Sleep-disordered breathing and nocturia in older adults. J Am Geriatr Soc 2004;52:957-960.
4. Kemmer H, Mathes AM, Dilk O, et al. Obstructive sleep apnea syndrome is associated with overactive bladder and urgency incontinence in men. Sleep 2009;32:271-275.
5. Margel D, Shochat T, Getzler O, et al. Continuous positive airway pressure reduces nocturia in patients with obstructive sleep apnea. Urology 2006;67:974-977.
Brandon R. Peters, M.D., is the writer on sleep for About.com, a neurology-trained sleep medicine specialist at Pulmonary and Sleep Associates of Marin in Novato, Calif., and consulting assistant professor at the Stanford Center for Sleep Sciences and Medicine. This Center is the birthplace of sleep medicine and includes research, clinical, and educational programs that have advanced the field and improved patient care for decades. To learn more, visit us at: sleep.stanford.edu.