Pituitary-gonadal and pituitary-thyroid axis hormone concentrations before and during a hypoglycemic clamp after sleep deprivation in healthy men

Evaluating the Spectrum of Sleep Abnormalities in Patients With Primary Hypothyroidism

Introduction and aim: Primary hypothyroidism is a common endocrine disorder. While thyroid dysfunction is recognized for impacting numerous bodily systems, the connection between thyroid disorders and sleep function remains unclear. Since sleep disorders seldom manifest as the sole presenting symptom of thyroid dysfunction, it is crucial to examine the interplay between thyroid function and sleep when implementing a comprehensive treatment approach for these individuals. This study aimed to assess sleep dysfunction in patients with primary hypothyroidism using validated questionnaires.

METHOD

This cross-sectional study included 81 participants attending the endocrinology outpatient department. The participants included those with both overt and subclinical primary hypothyroidism who were drug-naive or had a thyroid-stimulating hormone (TSH) level >4.5 µIU/L while on treatment. The study subjects were assessed based on various validated questionnaires for sleep disturbance.

RESULTS

The study predominantly comprised 64 (79%) female participants. Overall, poor sleepers in subclinical and overt hypothyroidism were 66.7 and 60.8%. The Berlin Risk Score Questionnaire showed the occurrence of sleep apnea to be 26.7% and 27.5% in subclinical and overt groups, respectively. However, the occurrence of sleep dysfunction did not correlate with TSH values alone.

CONCLUSION

Our findings demonstrate that sleep dysfunction is prevalent in patients with both overt and subclinical primary hypothyroidism. Furthermore, the severity of sleep disruption appears independent of the degree of thyroid dysfunction.

Sleep apnea syndrome associated with gonadal hormone imbalance (Review)

Patients with obstructive sleep apnea exhibit an increased risk of developing gonadal disorders. Because a notable number of people worldwide have sleep respiratory and reproductive disorders, it is essential to recognize the association between local upper airway dysfunction and its gonadal effects. Repeated breathing pauses cause sleep fragmentation, disorganization of sleep cycles and stages, sympathetic activation, intermittent hypoxemia and systemic inflammation. Nocturnal intermittent hypoxemia has a direct central effect on neurotransmitters, with disturbances in the normal production of hypothalamic-pituitary hormones. Awakenings and micro-awakenings at the end of apneic episodes produce a central stress responsible for hormonal changes and subsequent endocrine imbalances. The aim of the present study was to investigate the impact of obstructive sleep apnea syndrome (OSAS) on gonadal hormonal homeostasis and its consequences. Recognizing and understanding how local upper airway dysfunction causes gonadal imbalance may facilitate better care for patients with OSAS. Although there may be a direct relationship between sleep-disordered breathing and gonadal function mediated by hormones via the hypothalamic-pituitary-gonadal axis, to date, current therapies have not been effective.

Sleep, testosterone and cortisol balance, and ageing men

Sleep serves important biological functions, and influences health and longevity through endocrine and metabolic related systems. Sleep debt, circadian misalignment and sleep disruption from obstructive sleep apnea is widespread in modern society and accumulates with life because recovery sleep is not completely restorative. Accumulated disordered sleep throughout life impacts the ageing process and the development of age-related diseases. When epidemiological and interventional studies are considered collectively, sleep loss and lower sleep duration are associated with lower morning, afternoon and 24-h testosterone; as well as higher afternoon, but not morning or 24-h cortisol. These reciprocal changes imbalances anabolic-catabolic signaling because testosterone and cortisol are respectively the main anabolic and catabolic signals in man. Fixing testosterone-cortisol balance by means of a novel dual-hormone clamp mitigates the induction of insulin resistance by sleep restriction and provided the first proof-of-concept that the metabolic harm from sleep loss can be ameliorated by approaches that do not require sleeping more. Obstructive sleep apnea is associated with lower testosterone, even after controlling for age and obesity whereas the conclusion that continuous positive airway pressure therapy has no effect on testosterone is premature because available studies are underpowered and better-quality studies suggest otherwise. High dose testosterone therapy induces OSA, but more physiological dosing may not; and this effect may be transient or may dissipate with longer term therapy. Studies investigating the origin of the diurnal testosterone rhythm, the effect of circadian misalignment on testosterone-cortisol balance, and methods to mitigate metabolic harm, are required.

Effect of partial and total sleep deprivation on serum testosterone in healthy males: a systematic review and meta-analysis

BACKGROUND

Currently, there is no consensus on the effect of sleep deprivation on male serum testosterone. This systematic review and meta-analysis aimed to determine the association between partial/total sleep deprivation and male serum testosterone level.

METHODS

The literature related to sleep deprivation and male serum testosterone in the PubMed, Embase, and Cochrane Library databases were searched from their inception to July 15, 2021. Data were pooled using the Stata 15 software. The results were presented as standard mean differences (SMDs) with their 95% confidence intervals (CIs).

RESULTS

Eighteen studies involving 252 men were included in the systematic review and meta-analysis. The findings revealed that short-term partial sleep deprivation had no significant effect on male serum testosterone (SMD = -0.22; 95% CI: -0.5, 0.06; P = 0.13), while total sleep deprivation reduced the male testosterone levels (SMD = -0.64; 95% CI: -0.87, -0.42; P < 0.001). According to the intervention duration of total sleep deprivation, subgroup analysis was conducted by a fixed-effects model. The results revealed that the serum testosterone was significantly decreased after 24 h total sleep deprivation (SMD = - 0.67; 95% CI = - 0.93, -0.42, P < 0.001), as well as 40-48 h total sleep deprivation (SMD = - 0.74; 95% CI = - 1.22, -0.26, P = 0.002).

CONCLUSIONS

This meta-analysis revealed that total sleep deprivation (more than or equal to 24 h) reduces the male testosterone levels, while short-term partial sleep deprivation has no significant effect on male serum testosterone. Sleep duration plays a pivotal role in maintaining male serum testosterone levels.

Clamping Cortisol and Testosterone Mitigates the Development of Insulin Resistance during Sleep Restriction in Men

CONTEXT

Sleep loss in men increases cortisol and decreases testosterone, and sleep restriction by 3 to 4 hours/night induces insulin resistance.

OBJECTIVE

We clamped cortisol and testosterone and determined the effect on insulin resistance.

METHODS

This was a randomized double-blind, in-laboratory crossover study in which 34 healthy young men underwent 4 nights of sleep restriction of 4 hours/night under 2 treatment conditions in random order: dual hormone clamp (cortisol and testosterone fixed), or matching placebo (cortisol and testosterone not fixed). Fasting blood samples, and an additional 23 samples for a 3-hour oral glucose tolerance test (OGTT), were collected before and after sleep restriction under both treatment conditions. Cytokines and hormones were measured from the fasting samples. Overall insulin sensitivity was determined from the OGTT by combining complementary measures: homeostasis model assessment of insulin resistance of the fasting state; Matsuda index of the absorptive state; and minimal model of both fasting and absorptive states.

RESULTS

Sleep restriction alone induced hyperinsulinemia, hyperglycemia, and overall insulin resistance (P < 0.001 for each). Clamping cortisol and testosterone alleviated the development of overall insulin resistance (P = 0.046) and hyperinsulinemia (P = 0.014) by 50%. Interleukin-6, high-sensitivity C-reactive protein, peptide YY, and ghrelin did not change, whereas tumor necrosis factor-α and leptin changed in directions that would have mitigated insulin resistance with sleep restriction alone.

CONCLUSION

Fixing cortisol-testosterone exposure mitigates the development of insulin resistance and hyperinsulinemia, but not hyperglycemia, from sustained sleep restriction in men. The interplay between cortisol and testosterone may be important as a mechanism by which sleep restriction impairs metabolic health.

Age and time-of-day differences in the hypothalamo-pituitary-testicular, and adrenal, response to total overnight sleep deprivation

STUDY OBJECTIVES

In young men, sleep restriction decreases testosterone (Te) and increases afternoon cortisol (F), leading to anabolic-catabolic imbalance, insulin resistance, and other andrological health consequences. Age-related differences in the hypothalamo-pituitary-testicular/adrenal response to sleep restriction could expose older individuals to greater or lesser risk. We aimed to evaluate and compare the 24-h and time-of-day effect of sleep restriction on F, luteinizing hormone (LH), and Te in young and older men.

METHODS

Thirty-five healthy men, aged 18-30 (n = 17) and 60-80 (n =18) years, underwent overnight sleep deprivation (complete nighttime wakefulness) or nighttime sleep (10 pm to 6 am) with concurrent 10-min blood sampling in a prospectively randomized crossover study. F, LH, and Te secretion were calculated by deconvolution analysis.

RESULTS

Sleep deprivation had multiple effects on 24-h Te secretion with significant reductions in mean concentrations, basal, total and pulsatile secretion, and pulse frequency (each p < 0.05), in the absence of detectable changes in LH. These effects were most apparent in older men and differed according to age for some parameters: pulsatile Te secretion (p = 0.03) and Te pulse frequency (p = 0.02). Time-of-day analyses revealed that sleep restriction significantly reduced Te in the morning and afternoon, reduced LH in the morning in both age groups, and increased F in the afternoon in older men.

CONCLUSIONS

These data suggest a time-of-day dependent uncoupling of the regulatory control of the testicular axis and of F secretion. Future studies will need to directly verify these regulatory possibilities specifically and separately in young and older men.

CLINICAL TRIAL

Not applicable.

Sleep and the Testis

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.

The relationship between thyroid function tests and sleep quality: cross-sectional study

INTRODUCTION

The relationship between sleep and hormones have long been recognized. Studies indicated that sleep quality is one of the major modulatory effects on the endocrine system. In this study, we aimed to assess the serum concentration of thyroid hormones in individuals who suffered from low quality sleep.

MATERIAL AND METHODS

Based on the Pittsburgh Sleep Quality Index and ISMA Stress questionnaire, we divided 83 participants into two groups. Forty-one individuals with low quality sleep group and 42 with good quality sleep group, all from the male students of a medical school in Tehran, Iran, participated in this descriptive and cross-sectional study. Then, serum levels of thyroid hormones including free T₃, free T₄, and TSH were assessed and compared between two groups.

RESULTS

There were a significant increase in serum levels of FT₄ (p=0.01) and TSH (p=0.02). There were also meaningful correlations between sleep score and stress score (p=0.008) as well as stress score and FT₄ (p=0.03) in the case group.

CONCLUSIONS

The current study showed that thyroid function tests (T₄ and TSH) significantly rose in the poor sleep condition. We also found correlations between sleep score, stress score, and FT₄ in the poor sleep condition group that suggest low sleep quality can affect thyroid hormones.

The causes of adverse changes of testosterone levels in men

INTRODUCTION

As men age, progressive testosterone deficiency syndrome becomes an increasingly common problem. However, the decreased testosterone levels are not only the result of advanced age.

AREAS COVERED

PubMed search of published data on testosterone, nutritional deficiency, stress, sleep, and obesity. Many factors impact the male HPG axis (the hypothalamic-pituitary-adrenal), including body weight, calorific and nutritional value of a diet, the amount and quality of sleep, as well as the level of stress. In the case of persons of healthy weight, a below-average calorific value of a diet may decrease the levels of testosterone in men. On the other hand, the same caloric deficiency in obese persons may result in a neutral or positive impact on testosterone levels.

EXPERT OPINION

Many factors, including external, environmental and internal factors, influence testosterone levels. Undoubtedly, nutritional deficiency, and particularly of such nutrients as zinc, magnesium, vitamin D, together with low polyphenols intake, affects the HPG axis. The levels of mental and oxidative stress can also adversely impact the axis. Hence, a diagnosis of the cause of disturbance in testosterone levels depends on many factors and requires a broad range of research, as well as a change of patients' lifestyle.

Bowel preparation for colonoscopy may decrease the levels of testosterone in Korean men

Although colonoscopy is commonly conducted for medical check-ups in Korea, investigations for the influence of bowel preparation on various health conditions are insufficient. This cross-sectional study investigated whether bowel preparation has an influence on serum levels of testosterone. A total of 1114 men were divided into the bowel preparation group and control groups. The median total and free testosterone levels were significantly lower in the bowel preparation group (14.89 and 0.26 nmol/L, respectively) than in the control groups (15.72 and 0.28 nmol/L, respectively). The level of total testosterone significantly increased with age in the bowel preparation group (r = 0.103). The differences in the levels of total and free testosterone between the 2 groups were more prominent in younger men than in older men. In multivariate regression models, bowel preparation was independently associated with the levels of total and free testosterone. In these models, the interaction between age and bowel preparation was significant for the levels of total and free testosterone. In conclusion, bowel preparation may independently decrease the serum levels of total and free testosterone. The decline in testosterone was more evident in younger men than in older men.

Sex differences in sleep and sleep loss-induced cognitive deficits: The influence of gonadal hormones

Males and females can respond differentially to the same environmental stimuli and experimental conditions. Chronic sleep loss is a frequent and growing problem in many modern societies and has a broad variety of negative outcomes for health and well-being. While much has been done to explore the deleterious effects of sleep deprivation (SD) on cognition in both human and animal studies over the last few decades, very little attention has been paid to the part played by sex differences and gonadal steroids in respect of changes in cognitive functions caused by sleep loss. The effects of gonadal hormones on sleep regulation and cognitive performances are well established. Reduced gonadal function in menopausal women and elderly men is associated with sleep disturbances and cognitive decline as well as dementia, which suggests that sex steroids play a key role in modulating these conditions. Finding out whether there are sex differences in respect of the effect of insufficient sleep on cognition, and how neuroendocrine mediators influence cognitive impairment induced by SD could provide valuable insights into the best therapies for each sex. In this review, we aim to highlight the involvement of sex differences and gonadal hormone status on the severity of cognitive deficits induced by sleep deficiency in both human and animal studies.

Associations Between Sleep Deprivation and Salivary Testosterone Levels in Male University Students: A Prospective Cohort Study

Sleep deprivation is a common health problem that is growing rapidly worldwide and it is associated with short- and long-term impacts on health. The aim of this study was to detect potential predictors of salivary testosterone (sT) association with sleep deprivation in Arab male university students. In this prospective cohort study, 77 university male students in the age range of 18 to 26 years were divided into two groups, sleep-deprived (SD) participants and non-sleep-deprived (NSD) participants. Sleep deprivation was defined as sleeping less than 5 hr per night. Blood samples and sT were collected from fasting participants to measure serum levels of glucose, lipid profile, leptin, serotonin, sT, and body mass index (BMI) values. The multiple linear correlation model of high-density lipoprotein cholesterol (HDL-C), BMI, and serotonin was positively correlated with sT (r = .977, p < .05) in the SD group. No correlations were identified with sT in the NSD group. In the SD study group, the multiple linear regression model of HDL-C, BMI, and serotonin was significantly influenced by sT (R² = .955, p < .05). These predictors together explained approximately 96% of the variance in sT levels in the SD study group. No predictive variables for sT were reported in the NSD group. Results indirectly confirmed the presence of a positive association between sT and sleep deprivation in young men. This association is mediated by three factors, HDL-C, BMI, and serum serotonin, which are collectively considered as part of a significant physiological adaptation to sleep deprivation in young men.

Obstructive sleep apnea and hormones - a novel insight

Obstructive sleep apnea (OSA), a disorder characterized by repetitive collapse of the upper respiratory tract during sleep, occurs in about 4% of middle-aged men and 2% of women. The incidence of the disorder is rising due to an increase in obesity and ageing of the population. Patients with obstructive sleep apnea are at elevated risk of some endocrinal and metabolic disorders, which may lead to serious consequences including shortening of life expectancy. The recognition and understanding of interactions between local upper airway dysfunction and its endocrinal consequences is therefore vital. In this review we will focus on the influence of OSA on bone metabolism and endocrine homeostasis.

Effect of Sleep Extension on the Subsequent Testosterone, Cortisol and Prolactin Responses to Total Sleep Deprivation and Recovery

Total sleep deprivation (TSD) in humans is associated with altered hormonal levels, which may have clinical relevance. Less is known about the effect of an extended sleep period before TSD on these hormonal changes. Fourteen subjects participated in two experimental counterbalanced conditions (randomised cross-over design): extended sleep (21.00-07.00 h time in bed, EXT) and habitual sleep (22.30-07.00 h time in bed, HAB). For each condition, subjects performed two consecutive phases: six nights of either EXT or HAB. These nights were followed by 3 days in the sleep laboratory with blood sampling at 07.00 and 17.00 h at baseline (B-07.00 and B-17.00), after 24 and 34 h of continuous awakening (24 h-CA, 34 h-CA) and after one night of recovery sleep (R-07.00 and R-17.00) to assess testosterone, cortisol, prolactin and catecholamines concentrations. At 24 h of awakening, testosterone, cortisol and prolactin concentrations were significantly lower compared to B-07.00 and recovered basal levels after recovery sleep at R-07.00 (P < 0.001 for all). However, no change was observed at 34 h of awakening compared to B-17.00. No effect of sleep extension was observed on testosterone, cortisol and catecholamines concentrations at 24 and 34 h of awakening. However, prolactin concentration was significantly lower in EXT at B-07.00 and R-07.00 compared to HAB (P < 0.05, P < 0.001, respectively). In conclusion, 24 h of awakening inhibited gonadal and adrenal responses in healthy young subjects and this was not observed at 34 h of awakening. Six nights of sleep extension is not sufficient to limit decreased concentrations of testosterone and cortisol at 24 h of awakening but may have an impact on prolactin concentration.

Sex differences in sleep: impact of biological sex and sex steroids

Men and women sleep differently. While much is known about the mechanisms that drive sleep, the reason for these sex differences in sleep behaviour is unknown and understudied. Historically, women and female animals are underrepresented in studies of sleep and its disorders. Nevertheless, there is a growing recognition of sex disparities in sleep and rhythm disorders. Women typically report poorer quality and more disrupted sleep across various stages of life. Findings from clinical and basic research studies strongly implicate a role for sex steroids in sleep modulation. Understanding how neuroendocrine mediators and sex differences influence sleep is central to advancing our understanding of sleep-related disorders. The investigation into sex differences and sex steroid modulation of sleep is in its infancy. Identifying the mechanisms underlying sex and gender differences in sleep will provide valuable insights leading to tailored therapeutics that benefit each sex. The goal of this review is to discuss our current understanding of how biological sex and sex steroids influence sleep behaviour from both the clinical and pre-clinical perspective.

The relationship between sleep disorders and testosterone in men

Plasma testosterone levels display circadian variation, peaking during sleep, and reaching a nadir in the late afternoon, with a superimposed ultradian rhythm with pulses every 90 min reflecting the underlying rhythm of pulsatile luteinizing hormone (LH) secretion. The increase in testosterone is sleep, rather than circadian rhythm, dependent and requires at least 3 h of sleep with a normal architecture. Various disorders of sleep including abnormalities of sleep quality, duration, circadian rhythm disruption, and sleep-disordered breathing may result in a reduction in testosterone levels. The evidence, to support a direct effect of sleep restriction or circadian rhythm disruption on testosterone independent of an effect on sex hormone binding globulin (SHBG), or the presence of comorbid conditions, is equivocal and on balance seems tenuous. Obstructive sleep apnea (OSA) appears to have no direct effect on testosterone, after adjusting for age and obesity. However, a possible indirect causal process may exist mediated by the effect of OSA on obesity. Treatment of moderate to severe OSA with continuous positive airway pressure (CPAP) does not reliably increase testosterone levels in most studies. In contrast, a reduction in weight does so predictably and linearly in proportion to the amount of weight lost. Apart from a very transient deleterious effect, testosterone treatment does not adversely affect OSA. The data on the effect of sleep quality on testosterone may depend on whether testosterone is given as replacement, in supratherapeutic doses, or in the context abuse. Experimental data suggest that testosterone may modulate individual vulnerability to subjective symptoms of sleep restriction. Low testosterone may affect overall sleep quality which is improved by replacement doses. Large doses of exogenous testosterone and anabolic/androgenic steroid abuse are associated with abnormalities of sleep duration and architecture.

The relationship between sleep disorders and testosterone

PURPOSE OF REVIEW

This review describes evolving concepts and recent data on the relationship between serum testosterone levels and normal and disordered sleep.

RECENT FINDINGS

Sex-related differences in circadian rhythms and sleep physiology are in part due to organizational and activational effects of sex steroids. Testosterone affects the organization of circadian rhythms and the timing, but not the duration, of sleep. Increasing testosterone during puberty leads to later bedtimes. The diurnal variation in testosterone depends on sleep rather than circadian rhythm or season. Pubertal onset is heralded, well before virilization, by a luteinizing hormone level at least 3.7 U/l during sleep. Total sleep deprivation lowers testosterone, but sleep restriction only does so if it occurs in the first half of the night. The recovery of testosterone from sleep disruption is impaired in old as compared with young rodents. In men with obstructive sleep apnoea (OSA), low testosterone is related to obesity rather than the OSA itself, and improves with weight loss but inconsistently with continuous positive airway pressure (CPAP). Testosterone treatment only transiently worsens severity of OSA, which need not be considered a contraindication to its use.

SUMMARY

Testosterone treatment is unlikely to benefit sleep in men with secondary hypogonadism, for example due to obesity or depression, in contrast to the management of the underlying abnormality.