madman
Super Moderator
Abstract
Disordered sleep impairs neurocognitive performance, and is now recognized to cause metabolic ill-health. This review assesses the nascent relationship between insufficient, misaligned, and disrupted sleep with andrological health. High-quality cohort studies show a reduced sperm count in men with sleep disturbances. Well-designed interventional studies show a reduction in testosterone with sleep restriction. Studies of long-term shift workers show no effect of misaligned sleep on mean testosterone concentrations. Men with obstructive sleep apnea (OSA) and more severe hypoxemia have lower testosterone levels, although it is unknown if this relationship is entirely explained by concomitant obesity, or is reversible. Nevertheless, erectile dysfunction, which is common in men with OSA, is clinically improved when OSA is properly treated. Few studies manipulating sleep have been performed in older men, in whom the accumulation of sleep disturbances over decades of life may contribute to age-related illnesses. Improving sleep could ameliorate the development of these disorders.
Introduction
Sleep is an essential part of health maintenance, along with diet and exercise. Unfortunately, millions of Americans have abnormal sleep. More specifically, w32% of American adults have sleep insufficiency (<7 h per night) [1,2], 10% of Americans work evenings and nights, and up to an additional 6% of workers have rotating shifts, split shifts, or an otherwise irregular work schedule, causing misaligned sleep [3]. Obstructive sleep apnea (OSA), which causes disrupted sleep, affects approximately twice as many men compared to women [4]. The prevalence of moderate to severe OSA among men is estimated to be 10% in men aged 30-49 years and 17% in men aged 50-70 years [5].
Insufficient sleep duration, misaligned and disrupted sleep causes daytime sleepiness and impairs cognitive function. Alarmingly, surveys have shown that approximately 1 out of every 25 American adults had fallen asleep while driving during a 30-day period, leading to car accidents and fatalities in some instances [6]. Additionally, abnormal sleep is known to contribute to insulin resistance and cardiometabolic illness [7]. Perhaps less well known, but importantly, studies are beginning to show that poor sleep contributes to disorders of the testicular hormonal axis, including hypogonadism, infertility, and erectile dysfunction [8,9]. Testosterone levels exhibit a diurnal pattern. This diurnal pattern appears to be related to sleep rather than endogenous circadian rhythmicity. Testosterone rises, and peaks with the first episode of rapid-eye-movement (REM) sleep; these elevated levels are maintained until awakening and then decline [10].
*This review will discuss important findings between disordered sleep and the testicular axis, with a highlight on high-quality studies where 24-h testosterone was assessed to determine the diurnal secretion of testosterone. Additionally, an emphasis is placed on recently published findings within the past 5 years. New contributions to the literature include assessment of testosterone pulsatility and the impact of sleep restriction in older men.
*Insufficient sleep
-Sleep duration and reproductive health
-Sleep duration and testosterone
*Misaligned sleep
-Circadian misalignment and reproductive health
-Circadian misalignment and testosterone
*Disrupted sleep
-Disrupted sleep and reproductive health
-Disrupted sleep and testosterone
Summary and conclusions
The effects of disordered sleep on male reproductive health have been investigated in both epidemiological and interventional studies. Cohort studies have shown reduced sperm concentration in men with insufficient sleep. Cross-sectional data do not show impaired fertility in male shift workers. The literature is lacking large epidemiological studies of fertility in men with disrupted sleep (OSA). As cross-sectional studies are often confounded by multiple variables, future research should be in longitudinal studies in larger cohorts, which would broaden our knowledge on the effects of poor sleep.
Few studies have examined the effect of sleep restriction, circadian misalignment, and disrupted sleep on 24- h testosterone profiles: see Tables 1, 2, and 3. Furthermore, studies that sample testosterone more frequently throughout the day would elucidate changes in the diurnal variation of testosterone, including peak, nadir, and rate of decline. For example, studies attempting to assess circadian rhythmicity may require sampling every hour, whereas those attempting to determine pulsatility may need to measure testosterone as frequently as every 10 min. Of the studies measuring testosterone over 24 h, only one has examined an older population [17]. Considerable opportunities, therefore, exist to assess the impact of accumulated disordered sleep on illnesses that are more prevalent with aging, including andrological disorders. One such disorder is erectile dysfunction in association with OSA, in which reversal of OSA with adherent CPAP improves erectile function [52]. The effect of improving sleep on hypogonadism has not been directly assessed; however, it does appear that restricted sleep decreases testosterone, whereas the quality of studies examining the effects of misaligned and disrupted sleep on circulating testosterone is insufficient to draw definitive conclusions. Nevertheless, it does appear prudent for clinicians to provide education on proper sleep hygiene and to correct any disordered sleep in the hope that the health of their patients will ultimately be improved.
Disordered sleep impairs neurocognitive performance, and is now recognized to cause metabolic ill-health. This review assesses the nascent relationship between insufficient, misaligned, and disrupted sleep with andrological health. High-quality cohort studies show a reduced sperm count in men with sleep disturbances. Well-designed interventional studies show a reduction in testosterone with sleep restriction. Studies of long-term shift workers show no effect of misaligned sleep on mean testosterone concentrations. Men with obstructive sleep apnea (OSA) and more severe hypoxemia have lower testosterone levels, although it is unknown if this relationship is entirely explained by concomitant obesity, or is reversible. Nevertheless, erectile dysfunction, which is common in men with OSA, is clinically improved when OSA is properly treated. Few studies manipulating sleep have been performed in older men, in whom the accumulation of sleep disturbances over decades of life may contribute to age-related illnesses. Improving sleep could ameliorate the development of these disorders.
Introduction
Sleep is an essential part of health maintenance, along with diet and exercise. Unfortunately, millions of Americans have abnormal sleep. More specifically, w32% of American adults have sleep insufficiency (<7 h per night) [1,2], 10% of Americans work evenings and nights, and up to an additional 6% of workers have rotating shifts, split shifts, or an otherwise irregular work schedule, causing misaligned sleep [3]. Obstructive sleep apnea (OSA), which causes disrupted sleep, affects approximately twice as many men compared to women [4]. The prevalence of moderate to severe OSA among men is estimated to be 10% in men aged 30-49 years and 17% in men aged 50-70 years [5].
Insufficient sleep duration, misaligned and disrupted sleep causes daytime sleepiness and impairs cognitive function. Alarmingly, surveys have shown that approximately 1 out of every 25 American adults had fallen asleep while driving during a 30-day period, leading to car accidents and fatalities in some instances [6]. Additionally, abnormal sleep is known to contribute to insulin resistance and cardiometabolic illness [7]. Perhaps less well known, but importantly, studies are beginning to show that poor sleep contributes to disorders of the testicular hormonal axis, including hypogonadism, infertility, and erectile dysfunction [8,9]. Testosterone levels exhibit a diurnal pattern. This diurnal pattern appears to be related to sleep rather than endogenous circadian rhythmicity. Testosterone rises, and peaks with the first episode of rapid-eye-movement (REM) sleep; these elevated levels are maintained until awakening and then decline [10].
*This review will discuss important findings between disordered sleep and the testicular axis, with a highlight on high-quality studies where 24-h testosterone was assessed to determine the diurnal secretion of testosterone. Additionally, an emphasis is placed on recently published findings within the past 5 years. New contributions to the literature include assessment of testosterone pulsatility and the impact of sleep restriction in older men.
*Insufficient sleep
-Sleep duration and reproductive health
-Sleep duration and testosterone
*Misaligned sleep
-Circadian misalignment and reproductive health
-Circadian misalignment and testosterone
*Disrupted sleep
-Disrupted sleep and reproductive health
-Disrupted sleep and testosterone
Summary and conclusions
The effects of disordered sleep on male reproductive health have been investigated in both epidemiological and interventional studies. Cohort studies have shown reduced sperm concentration in men with insufficient sleep. Cross-sectional data do not show impaired fertility in male shift workers. The literature is lacking large epidemiological studies of fertility in men with disrupted sleep (OSA). As cross-sectional studies are often confounded by multiple variables, future research should be in longitudinal studies in larger cohorts, which would broaden our knowledge on the effects of poor sleep.
Few studies have examined the effect of sleep restriction, circadian misalignment, and disrupted sleep on 24- h testosterone profiles: see Tables 1, 2, and 3. Furthermore, studies that sample testosterone more frequently throughout the day would elucidate changes in the diurnal variation of testosterone, including peak, nadir, and rate of decline. For example, studies attempting to assess circadian rhythmicity may require sampling every hour, whereas those attempting to determine pulsatility may need to measure testosterone as frequently as every 10 min. Of the studies measuring testosterone over 24 h, only one has examined an older population [17]. Considerable opportunities, therefore, exist to assess the impact of accumulated disordered sleep on illnesses that are more prevalent with aging, including andrological disorders. One such disorder is erectile dysfunction in association with OSA, in which reversal of OSA with adherent CPAP improves erectile function [52]. The effect of improving sleep on hypogonadism has not been directly assessed; however, it does appear that restricted sleep decreases testosterone, whereas the quality of studies examining the effects of misaligned and disrupted sleep on circulating testosterone is insufficient to draw definitive conclusions. Nevertheless, it does appear prudent for clinicians to provide education on proper sleep hygiene and to correct any disordered sleep in the hope that the health of their patients will ultimately be improved.
