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:
chronic renal (kidney) failure
congestive heart failure
benign prostatic hypertrophy (enlarged prostate)
sleep disorders, such as obstructive sleep apnea, insomnia or restless leg syndrome
“Combined with other management strategies, physical activity may provide a strategy for the management of BPH-related outcomes, particularly nocturia,” Wolin and colleagues wrote.
There are several possible mechanisms by which physical activity can protect against nocturia, including reducing body size, improving sleep, decreasing sympathetic nervous system activity and lowering levels of systemic inflammation.
Future studies should explore physical activity as a potential symptom-management strategy, “with particular attention to the dose of physical activity necessary and the mechanisms that might underlie the association,” Wolin and colleagues wrote.
Wolin is an epidemiologist whose research focuses on the role of lifestyle in reducing the risk of cancer and other chronic diseases, and on improving outcomes. She is an associate professor in the departments of Surgery and Public Health Sciences of Loyola University Chicago Stritch School of Medicine.
Co-authors of the study are Robert Grubb III, Ratna Pakpahan, Gerald Andriole and Siobhan Sutcliffe of Washington University in St. Louis; and Lawrence Ragard and Jerome Mabie, who work in private industry.
Frequent Urination at Night
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. 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.
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 . According to Michael J. Thorpy, MD, and Jan Yager, PhD, authors of The Encyclopedia of Sleep and Sleep Disorders , relief of the sleep apnea syndrome will alleviate the nocturia.
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.
The study is titled “Physical Activity and Benign Prostatic Hyperplasia-Related Outcomes and Nocturia.” It was supported by a grant from the National Institute of Diabetes and Digestive and Kidney Diseases.
Loyola University Health System (LUHS) is a member of Trinity Health. Based in the western suburbs of Chicago, LUHS is a quaternary care system with a 61-acre main medical center campus, the 36-acre Gottlieb Memorial Hospital campus and more than 30 primary and specialty care facilities in Cook, Will and DuPage counties. The medical center campus is conveniently located in Maywood, 13 miles west of the Chicago Loop and 8 miles east of Oak Brook, Ill. The heart of the medical center campus is a 559-licensed-bed hospital that houses a Level 1 Trauma Center, a Burn Center and the Ronald McDonald® Children’s Hospital of Loyola University Medical Center. Also on campus are the Cardinal Bernardin Cancer Center, Loyola Outpatient Center, Center for Heart & Vascular Medicine and Loyola Oral Health Center as well as the LUC Stritch School of Medicine, the LUC Marcella Niehoff School of Nursing and the Loyola Center for Fitness. Loyola’s Gottlieb campus in Melrose Park includes the 255-licensed-bed community hospital, the Professional Office Building housing 150 private practice clinics, the Adult Day Care, the Gottlieb Center for Fitness, Loyola Center for Metabolic Surgery and Bariatric Care and the Loyola Cancer Care & Research at the Marjorie G. Weinberg Cancer Center at Melrose Park.
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