Men who exercise less are more likely to wake up to urinate

Men who are physically active are at lower risk of nocturia (waking up at night to urinate), according to a study led by a Loyola University Chicago Stritch School of Medicine researcher.

The study, by Kate Wolin, ScD, and colleagues, is published online ahead of the print edition in Medicine & Science in Sports & Exercise, the official journal of the American College of Sports Medicine.

Nocturia is the most common and bothersome lower urinary tract symptom in men. It can be due to an enlarged prostate known as benign prostatic hyperplasia (BPH) in which the enlarged prostate squeezes down on the urethra. Other causes include overproduction of urine, low bladder capacity and sleep disturbances. Nocturia increases with age and is estimated to occur in more than 50 percent of men 45 and older.

Wolin and colleagues analyzed data from a large, ongoing clinical trial called the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial (PLCO). Men ages 55 to 74 were eligible for the trial. The study included questions on BPH-related outcomes, including enlarged prostate, elevated PSA levels and nocturia. PLCO also asked men about physical activity and other lifestyle factors.

Wolin’s analysis included 28,404 men in the PLCO trial who had BPH outcomes before enrolling in the study (prevalent group) and 4,710 men who had newly developed BPH (incident group).

Among men in the incident group, those who were physically active one or more hours per week were 13 percent less likely to report nocturia and 34 percent less likely to report severe nocturia than men who reported no physical activity. (Nocturia was defined as waking two or more times during the night to urinate; severe nocturia was defined as waking three or more times to urinate.)

What Causes Nighttime Urination?

Aging is one of the biggest contributing factors to nighttime urination. As we age, the body produces less of the anti-diuretic hormone that helps us retain fluid resulting in increased urine production—especially at night. Muscles in the bladder can also become weak over time, making it more difficult to hold urine in the bladder.

Aging is not the only contributing factor to nighttime urination. Other common causes include:

chronic urinary tract infections
drinking excess fluids (especially caffeinated and alcoholic ones) before bed
bacterial infection in the bladder
medications that encourage urination (diuretics)

Women may experience frequent urination as a result of pregnancy and childbirth, which can weaken the bladder and pelvic floor muscles.

In some cases, nighttime urination is a symptom of an underlying medical condition. Disease and conditions associated with frequent urination include: