Getting up once to relieve your bladder during sleep hours is usually not particularly troublesome. However, when it happens two or more times, it can negatively impact one’s quality of life because of sleep disruption, daytime fatigue, an increased risk of fatigue-related accidents and an increased risk of fall-related nighttime injuries. Fatigue has a negative effect on just about everything, even influencing us to mindlessly eat.
Nocturia is the medical term for the need to awaken from sleep to urinate. One’s natural response is to think urinary bladder problem and seek a consultation with a urologist, the type of doctor who specializes in the urinary system. Although nocturia manifests itself via the bladder and much of the time is a urological issue, it is often not a bladderproblem. Rather, the kidneys are frequently culprits in contributing to the condition.
The kidneys are remarkable organs that can multitask like no other. They not only filter blood to remove waste products, but are also responsible for other vital body functions: They are in charge of maintaining the proper fluid volume within our blood stream. They regulate the levels of our electrolytes including sodium, potassium, chloride, etc. They keep our blood pH (indicator of acidity) at a precise level to maintain optimal function. They are key players in the regulation of blood pressure. Furthermore—and unbeknownst to many—they are responsible for the production of several important hormones: calcitrol (calcium regulation), erythropoietin (red blood cell production), and renin (blood pressure regulation). The kidneys regulate our blood volume by concentrating or diluting our urine depending on our state of hydration. When we are over-hydrated, the kidneys dilute the urine to rid our bodies of excess fluid, resulting in virtually clear urine. When we are dehydrated, the kidneys concentrate urine to preserve our fluid volume, resulting in very concentrated urine that can look as dark as apple cider.
Nocturia correlates with aging and the associated decline in kidney function and decreased ability to concentrate urine. Although having an enlarged prostate may certainly contribute to nocturia, it is obviously much more complicated than this since women do not have prostates and nocturia is equally prevalent in men and women. As simple as getting up at night to urinate sounds, it is actually a complex condition often based upon multiple factors that require careful evaluation in order to sort out and treat appropriately. When a urology consultation is sought, our goal is to distinguish between urological and non-urological causes for nighttime urinating. It often comes down to one of three factors: nighttime urine production by the kidneys; capacity of the urinary bladder; and sleep status. In the elderly population, excessive nighttime urine production is a factor almost 90% of the time.
Nocturia can ultimately be classified into one or more of 5 categories: global polyuria (making too much urine, day and night); nocturnal polyuria (making too much urine at night); reduced bladder capacity; sleep disorders; and circadian clock disorders (problems with our bio-rhythms). Global polyuria can result from excessive fluid intake from overenthusiastic drinking or from dehydration from poorly controlled diabetes mellitus (sugar diabetes). The pituitary gland within our brain manufactures an important hormone responsible for water regulation. This hormone is ADH—anti-diuretic hormone—and it works by giving the message to the kidneys to concentrate urine. Diabetes insipidus is a disease of either kidney origin—in which the kidneys do not respond to ADH—or pituitary origin—in which there is deficient secretion of ADH. In either case, lots of urine will be made, resulting in frequent urination, both daytime and nighttime. Medications including diuretics, SSRIs (selective serotonin reuptake inhibitors), calcium blockers, tetracycline and lithium may induce global polyuria.
Nocturnal polyuria may be on the basis of excessive fluid intake, especially diuretic beverages including caffeine and alcohol, a nocturnal defect in the secretion of ADH, and unresponsiveness of the kidneys to the action of ADH. Congestive heart failure, sleep apnea and kidney insufficiency may also play a role. Certain conditions result in accumulation of fluids in tissues of the body such as the legs (peripheral edema); when lying down to sleep, the fluid is no longer under the same pressures as determined by gravity, and returns to the intravascular (within the blood vessels) compartment. It is then subject to being released from the kidneys as urine. Such conditions include heart, kidney and liver impairment, nephrotic syndrome, malnutrition and venous stasis. Circadian clock disorders cause reduced ADH secretion or activity, resulting in dilute urine that causes nocturia.
Nocturia may also be caused by primary sleep disorders including insomnia, restless leg syndrome, narcolepsy, and arousal disorders (sleepwalking, nightmares, etc.)
There are numerous urological causes of reduced bladder capacity. Any abnormal process that occurs within the bladder can irritate its delicate lining, causing a reduced capacity: bladder infections, bladder stones, bladder cancer, bacterial cystitits, radiation cystitis, and interstitial cystitis. An overactive bladder—a bladder that “squeezes without its owner’s permission”—can cause nocturia. Some people have small bladder capacities on the basis of scarring, radiation, or other forms of damage. Prostate enlargement commonly gives rise to nocturia, as can many neurological diseases that often have profound effects on bladder function. Incomplete bladder emptying can give rise to frequent urination since the bladder is already starting out on a bias of being partially filled. This problem can occur with prostate enlargement, scar tissue in the urethra, neurologic issues, and bladder prolapse.
The principal diagnostic tool for nocturia is the frequency-volume chart (FVC), a simple test that can effectively guide diagnosis and treatment. This is a 24-hour record of the time of urination and volume of urination, requiring a clock, pencil, paper and measuring cup. Typical bladder capacity is 10–12 ounces with 4–6 urinations per day. Reduced bladder capacity is a condition in which frequent urination occurs with low bladder capacities, for example, 3–4 ounces per void. Global polyuria is a condition in which bladder volumes are full and appropriate and the frequency occurs both daytime and nighttime. Nocturnal polyuria is nocturnal urinary frequency with full and appropriate volumes, with daytime voiding patterns being normal.
Lifestyle modifications to improve nocturia include the following: preemptive voiding before bedtime, intentional nocturnal and late afternoon dehydration, salt restriction, dietary restriction of caffeine and alcohol, adjustment of medication timing, use of compression stockings with afternoon and evening leg elevation, and use of sleep medications as necessary.
Urological issues may need to be managed with medications that relax or shrink the prostate when the issue is prostate obstruction, and bladder relaxants for overactive bladder. For nocturnal polyuria, synthetic ADH (an orally disintegrating sublingual tablet) in dosages of 50-100 micrograms for men and 25 micrograms for women can be highly effective.
Bottom Line: Nocturia should be investigated to determine its cause, which may often in fact be related to conditions other than urinary tract issues. Nighttime urination is not only bothersome, but may also pose real health risks. Chronically disturbed sleep can lead to a host of collateral wellness issues.
Andrew Siegel, MD
Author of Male Pelvic Fitness: Optimizing Sexual and Urinary Health; available in e-book (Kindle, iBooks, Nook) and coming soon in paperback.
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Tags: ADH, aging, Andrew Siegel MD, apnea, bladder, cystitis, diabetes, diabetes insipidus, edema, excessive drinking, failure to empty, fatigue, frequency-volume chart, kidneys, male pelvic fitness, narcolepsy, nighttime urinating, nocturia, overactive bladder, polyuria, prostate, prostate enlargement, reduced bladder capacity, restless leg syndrome, sleep disorders, urinary frequency, urology