"Targeted counseling regarding sleep hygiene improvements may positively affect several urologic disorders while also facilitating a host of overall health benefits," write Hudson Pierce and Bilal Chughtai, MD.
On average, humans spend one-third of their lives asleep. Sleep is a restorative physiologic state and is a vital factor in physical and mental health maintenance, memory consolidation, and immune defense enhancement (Ann N Y Acad Sci 2010; 1193:48–59). Although sleep quality is difficult to precisely evaluate, it is a widely used construct measured subjectively by validated questionnaires and objectively by polysomnography or actigraphy. Sleep duration is commonly used as a proxy for assessment of sleep health. Adults typically require 7 to 9 hours of sleep per night, but over 35% of adults report sleeping less than 7 hours per night, and nearly 30% sleep less than 6 hours (Sleep 2015; 38:829-32).
Poor sleep has been associated with a number of serious adverse health effects, including obesity, type 2 diabetes, cardiovascular disease, and mortality (Sleep 2010; 33:585–92). Recent evidence has further linked impaired sleep with urologic disease, notably erectile dysfunction (ED) and lower testosterone levels (table) (J Urol 2018; 199[4S]:e560, abs. PD27-08; World J Urol 2019; 37:1449-53). Nocturia has repeatedly been associated with poor sleep quality, and evidence suggests this relationship is bidirectional.
Targeted counseling regarding sleep hygiene improvements may positively affect several urologic disorders while also facilitating a host of overall health benefits. Here we discuss the significant impact of sleep on men with urologic disease.
Sleep and erectile function
The link between ED and sleep disorders is well established. Numerous studies have reported an increased incidence of ED in men with obstructive sleep apnea (OSA) ranging from 47% to 80%(World J Mens Health Aug 14, 2018 [Epub ahead of print]). Insomnia has been identified as an independent risk factor for sexual dysfunction in older men, theorized to be related to decreases in testosterone (World J Mens Health Aug 14, 2018 [Epub ahead of print]). In a recent study, men working nonstandard shifts who reported poor sleep quality had higher rates of erectile dysfunction than men who subjectively slept better (Urology 2017; 102:121-5).
Both restless legs syndrome and periodic limb movements are associated with an increased prevalence of ED (World J Mens Health Aug 14, 2018 [Epub ahead of print]), although as with other sleep disorders the underlying relationship remains unclear. Given the high incidence of poor sleep in the overall population, increased attention has recently turned to the impact of poor sleep on erectile function in men without specific sleep disorders.
In a survey study, 377 men with a mean age of 46 years completed validated sleep and erectile function questionnaires and were queried about comorbidities, smoking status, shift work status, and caffeine and medication use (J Urol 2018; 199[4S]:e560, abs. PD27-08). Multivariable regression analysis controlled for a number of dependent variables, including age, body mass index, and burden of comorbidity. The authors found that poor sleep quality was independently associated with worsening erectile function. Notably, erectile function in this same group improved after patients were given instructions on improving sleep hygiene.
Further research characterizing this association is needed, but it is apparent that sleep health is an essential consideration for optimizing sexual function in men.
Next: Sleep and testosterone levelsSleep and testosterone levels
Numerous studies in humans and animals have reported an association between impaired sleep and lower serum testosterone levels (J Urol 2018; 199[4S]:e560, abs. PD27-08). Low testosterone has been associated with a number of adverse health effects, including decreased libido, depressed mood, sexual dysfunction, and poor concentration (J Clin EndocrinolMetab 2006; 91:4335-43).
In a recent study, serum testosterone levels in 9,756 men aged 16-80 years were analyzed utilizing a multivariable regression model controlling for comorbidities and baseline demographics World J Urol 2019; 37:1449-53). The authors found an association between lower serum testosterone levels and impaired sleep, showing a decrease of 5.85 ng/dL in serum testosterone for each hour of sleep lost (World J Urol 2019; 37:1449-53). Although it is unlikely that a decrease of 5.85 ng/dL in testosterone levels per hour of sleep lost will dramatically affect overall health, sleep improvement should still be an important part of the treatment algorithm to maintain or increase testosterone levels.
Sleep and nocturia
Nocturia is a widely prevalent condition that increases with age. Nocturia is associated with lower quality of life and has been associated with a number of comorbidities, including falls and fractures, diabetes, obesity, coronary artery disease, depression, and increased risk of all-cause mortality (Nat Rev Urol 2016; 13:573-83). Although numerous studies have identified nocturia as an independent predictor of sleep disturbance (J Urol 2011; 185:2223-8), there is evidence suggesting that the relationship between nocturia and sleep disruption is not necessarily unidirectional. It is generally supposed that nocturia causes patients to awaken, but studies have suggested that poor sleep itself results in patients waking up and realizing they need to urinate.
On one hand, successful treatment of nocturia and overall lower urinary tract symptoms (LUTS) has been shown to lead to improvement in sleep quality, while another study reported that poor sleep quality was associated with incident LUTS, including nocturia alone (J Urol 2011; 185:2223-8; J Urol 2012; 188:2288-93). Sleep apnea in particular has been identified as potentially playing a causal role in some cases of incident nocturia, but even healthy adults may suffer from sleep disturbance that causes them to awaken and then void.
A broader consideration is the potential multidirectional association among sleep, urologic symptoms, and non-urologic disease. Conditions known to be negatively affected by poor sleep quality, such as diabetes and cardiovascular disease, have also been identified as contributing factors in urologic symptoms (Eur Urol 2007; 52:407-15). Ultimately, assessment of sleep should be considered an essential aspect of care for patients with urologic disease, which includes providing counseling and appropriate referrals for sleep evaluations.
As leaders in men’s health, urologists can offer appropriate initial counseling on improving sleep hygiene. This includes practices such as routine exercise, avoiding stimulant use such as caffeine or nicotine before bedtime, following a regular bedtime routine, exposure to natural light during the day, and ensuring a good sleep environment (Sleep Med Rev 2015; 22:23-36). Good sleep hygiene can have a significant positive impact on health, both globally and urologically.
Mr. Pierce is a medical student, and Dr. Chughtai is associate professor of urology, Weill Cornell Medical College, New York.
Section Editor Steven A. Kaplan, MD, is professor of urology at the Icahn School of Medicine at Mount Sinai and director benign urologic diseases, Mount Sinai Health System, New York. Follow him on Twitter at @MaleHealthDoc.