Effects of partial sleep deprivation on proinflammatory cytokines, growth hormone, and steroid hormone concentrations during repeated brief sprint interval exercise

Current Aspects of Selected Factors to Modulate Brain Health and Sports Performance in Athletes

This review offers a comprehensive evaluation of current aspects related to nutritional strategies, brain modulation, and muscle recovery, focusing on their applications and the underlying mechanisms of physiological adaptation for promoting a healthy brain, not only in athletes but also for recreationally active and inactive individuals. We propose that applying the rule, among others, of good sleep, regular exercise, and a properly balanced diet, defined as "SPARKS", will have a beneficial effect on the function and regeneration processes of the gut-brain-muscle axis. However, adopting the formula, among others, of poor sleep, stress, overtraining, and dysbiosis, defined as "SMOULDER", will have a detrimental impact on the function of this axis and consequently on human health as well as on athletes. Understanding these dynamics is crucial for optimizing brain health and cognitive function. This review highlights the significance of these factors for overall well-being, suggesting that adopting the "SPARKS" approach may benefit not only athletes but also older adults and individuals with health conditions.

Narrative review: The role of circadian rhythm on sports performance, hormonal regulation, immune system function, and injury prevention in athletes

Objectives

This study was a narrative review of the importance of circadian rhythm (CR), describes the underlying mechanisms of CR in sports performance, emphasizes the reciprocal link between CR, endocrine homeostasis and sex differences, and the unique role of the circadian clock in immune system function and coordination.

Method

As a narrative review study, a comprehensive search was conducted in PubMed, Scopus, and Web of Science (core collection) databases using the keywords "circadian rhythm", "sports performance", "hormonal regulation", "immune system", and "injury prevention". Inclusion criteria were studies published in English and peer-reviewed journals until July 2023. Studies that examined the role of CR in sports performance, hormonal status, immune system function, and injury prevention in athletes were selected for review.

Results

CR is followed by almost all physiological and biochemical activities in the human body. In humans, the superchiasmatic nucleus controls many daily biorhythms under solar time, including the sleep-wake cycle. A body of literature indicates that the peak performance of essential indicators of sports performance is primarily in the afternoon hours, and the evening of actions occurs roughly at the peak of core body temperature. Recent studies have demonstrated that the time of day that exercise is performed affects the achievement of good physical performance. This review also shows various biomarkers of cellular damage in weariness and the underlying mechanisms of diurnal fluctuations. According to the clock, CR can be synchronized with photonic and non-photonic stimuli (i.e., temperature, physical activity, and food intake), and feeding patterns and diet changes can affect CR and redox markers. It also emphasizes the reciprocal links between CR and endocrine homeostasis, the specific role of the circadian clock in coordinating immune system function, and the relationship between circadian clocks and sex differences.

Conclusion

The interaction between insufficient sleep and time of day on performance has been established in this study because it is crucial to balance training, recovery, and sleep duration to attain optimal sports performance.

Impact of COVID-19 pandemic on cross-country runners: changes in training, sleep, diet, and mental health

Objective: Determine the impact of the COVID-19 pandemic on the changes in training, sleep, diet, and mental health of cross-country runners. Participants: Cross-country runners from NCAA Division II institutes. Methods: Wilcoxon signed-rank test was performed to analyze survey responses to ordinal questions on the survey while Spearman's rank correlation analysis (ρ) was used to calculate correlation between after the start of pandemic questions. Data was marked significant at p < 0.05. Results: Analysis of the survey responses revealed that cross-country runners were more likely to experience feelings of depression (p < 0.001), lack of motivation (p < 0.001), and higher daily stress (p < 0.001) after the start of the pandemic. After the start of the pandemic, runners running less days per week were more likely to report an increased feeling of depression (ρ=-0.315, p = 0.008) and lack of motivation (ρ=-0.458, p < 0.001). Conclusions: The present study underscores the importance of training, sleep, diet, and mental health amongst cross-country runners.

Primum non nocere; It's time to consider altitude training as the medical intervention it actually is!

Sleep is one of the most important aspects of recovery, and is known to be severely affected by hypoxia. The present position paper focuses on sleep as a strong moderator of the altitude training-response. Indeed, the response to altitude training is highly variable, it is not a fixed and classifiable trait, rather it is a state that is determined by multiple factors (e.g., iron status, altitude dose, pre-intervention hemoglobin mass, training load, and recovery). We present an overview of evidence showing that sleep, and more specifically the prolonged negative impact of altitude on the nocturnal breathing pattern, affecting mainly deep sleep and thus the core of physiological recovery during sleep, could play an important role in intra- and interindividual variability in the altitude training-associated responses in professional and recreational athletes. We conclude our paper with a set of suggested recommendations to customize the application of altitude training to the specific needs and vulnerabilities of each athlete (i.e., primum non nocere). Several factors have been identified (e.g., sex, polymorphisms in the TASK2/KCNK5, NOTCH4 and CAT genes and pre-term birth) to predict individual vulnerabilities to hypoxia-related sleep-disordered breathing. Currently, polysomnography should be the first choice to evaluate an individual's predisposition to a decrease in deep sleep related to hypoxia. Further interventions, both pharmacological and non-pharmacological, might alleviate the effects of nocturnal hypoxia in those athletes that show most vulnerable.

Resistance Training Improves Sleep and Anti-Inflammatory Parameters in Sarcopenic Older Adults: A Randomized Controlled Trial

Sleep and exercise have an important role in the development of several inflammation-related diseases, including sarcopenia. Objective: To investigate the effects of 12 weeks of resistance exercise training on sleep and inflammatory status in sarcopenic patients. Methods: A randomized controlled trial comparing resistance exercise training (RET) with a control (CTL) was conducted. Outcomes were obtained by physical tests, polysomnography, questionnaires, isokinetic/isometric dynamometry tests, and biochemical analysis. Results: Time to sleep onset (sleep latency) was reduced in the RET group compared to the CTL group (16.09 ± 15.21 vs. 29.98 ± 16.09 min; p = 0.04) after the intervention. The percentage of slow-wave sleep (N3 sleep) was increased in the RET group (0.70%, CI: 7.27−16.16 vs. −4.90%, CI: 7.06−16.70; p = 0.04) in an intention to treat analysis. Apnea/hour was reduced in the RET group (16.82 ± 14.11 vs. 7.37 ± 7.55; p = 0.001) and subjective sleep quality was improved compared to the CTL (−1.50; CI: 2.76−6.14 vs. 0.00; CI: 1.67−3.84 p = 0.02) in an intention-to-treat analysis. Levels of interleukin-10 (IL-10) (2.13 ± 0.80 vs. 2.51 ± 0.99; p < 0.03) and interleukin-1 receptor antagonist (IL-1ra) (0.99 ± 0.10 vs. 0.99 ± 0.10 ng/mL; p < 0.04; delta variation) were increased in the RET group. Conclusions: RET improves sleep parameters linked to muscle performance, possibly due to an increase in anti-inflammatory markers in older sarcopenic patients.

Chronotype and Social Jetlag Influence Performance and Injury during Reserve Officers' Training Corps Physical Training

Sleep and circadian rhythms are critically important for optimal physical performance and maintaining health during training. Chronotype and altered sleep may modulate the response to exercise training, especially when performed at specific times/days, which may contribute to musculoskeletal injury. The purpose of this study was to determine if cadet characteristics (chronotype, sleep duration, and social jetlag) were associated with injury incidence and inflammation during physical training. Reserve Officers' Training Corps (ROTC) cadets (n = 42) completed the Morningness/Eveningness Questionnaire to determine chronotype, and 1-week sleep logs to determine sleep duration and social jetlag. Salivary IL-6 was measured before and after the first and fourth exercise sessions during training. Prospective injury incidence was monitored over 14 weeks of training, and Army Physical Fitness Test scores were recorded at the conclusion. Chronotype, sleep duration, and social jetlag were assessed as independent factors impacting IL-6, injury incidence, and APFT scores using ANOVAs, chi-squared tests, and the t-test where appropriate, with significance accepted at p < 0.05. Evening chronotypes performed worse on the APFT (evening = 103.8 ± 59.8 vs. intermediate = 221.9 ± 40.3 vs. morning = 216.6 ± 43.6; p < 0.05), with no difference in injury incidence. Sleep duration did not significantly impact APFT score or injury incidence. Social jetlag was significantly higher in injured vs. uninjured cadets (2:40 ± 1:03 vs. 1:32 ± 55, p < 0.05). Exercise increased salivary IL-6, with no significant effects of chronotype, sleep duration, or social jetlag. Evening chronotypes and cadets with social jetlag display hampered performance during morning APFT. Social jetlag may be a behavioral biomarker for musculoskeletal injury risk, which requires further investigation.

Sleep and Athletic Performance: Impacts on Physical Performance, Mental Performance, Injury Risk and Recovery, and Mental Health: An Update

Sleep health is an important consideration for athletic performance. Athletes are at high risk of insufficient sleep duration, poor sleep quality, daytime sleepiness and fatigue, suboptimal sleep schedules, irregular sleep schedules, and sleep and circadian disorders. These issues likely have an impact on athletic performance via several domains. Sleep loss and/or poor sleep quality can impair muscular strength, speed, and other aspects of physical performance. Sleep issues can also increase risk of concussions and other injuries and impair recovery after injury. Cognitive performance is also impacted in several domains, including vigilance, learning and memory, decision making, and creativity.

Effects of High-Intensity Interval Exercise and Acute Partial Sleep Deprivation on Cardiac Autonomic Modulation

Sleep deprivation in healthy adults has been associated with disrupted autonomic nervous system function, which in turn has been linked to cardiovascular health. High-intensity interval exercise (HIIE) may affect both sleep and cardiac autonomic modulation. Purpose: To investigate the impact of acute partial sleep deprivation on autonomic cardiac regulation before and after an acute bout of HIIE and the length of time for the autonomic system to return to resting levels. Methods: Fifteen healthy males with body mass index (BMI) of 25.8 ± 2.7 kg·m^-2 and age 31 ± 5 y participated in a reference sleep (~9.5 hr) with no HIIE (RS), a reference sleep with HIIE (RSX), and an acute partial sleep deprivation (~3.5 hr) with HIIE (SDX). HIIE was performed in 3:2 intervals at 90% and 40% of VO₂ reserve. Autonomic regulation through HRV selected time and frequency domain indices were recorded the night before, the morning of the next day, 1 hr-, 2 hr-, 4hr-, and 6-hr post-exercise. Results: HIIE performed in a 3:2 W:R ratio decreased the HRV (p < .05) at 1-hr post exercise and it took up to 4 hr to return to baseline levels. Parasympathetic related HRV indices increased the morning of the next day for SDX (p < .05). Acute partial sleep deprivation and HIIE did not modify the HRV responses compared to reference sleep and HIIE. Conclusion: HRV disturbance typically seen in responses to an acute episode of HIIE is not influenced by acute partial sleep deprivation.

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.

Overnight Immune Regulation and Subjective Measures of Sleep: A Three Night Observational Study in Adolescent Track and Field Athletes

To ensure health maintenance of young athletes, immunological stress due to physical exercise has to be balanced for performance development and health maintenance. Sleep is an important influencing factor for immune regulation because of its regenerating effect. In an attempt to assess overnight immune regulation, this observational study aimed to examine associations between changes in capillary immunological blood markers and measures of sleep in adolescent athletes. Over a period of three nights, 12 male (n = 6) and female (n = 6) adolescent track and field athletes aged 16.4 ± 1.1 years were monitored for their sleep behavior (e.g., sleep duration, sleep depth) and immune regulation by using subjective (e.g., sleep) and objective (capillary blood markers) measurement tools. Over the 4 day (three nights), athletes followed their daily routines (school, homework, free time activities, and training). Training was performed for different disciplines (sprint, hurdles, and long-jump) following their daily training routines. Training included dynamic core stability training, coordination training, speed training, resistance training, and endurance training. Capillary blood samples were taken 30-45 min after the last training session (10:00-12:00 a.m. or 5:00-6:00 p.m.) and every morning between 7:00 and 10:00 a.m. Changes in capillary blood markers from post-training to the next morning and morning-to-morning fluctuations in capillary blood markers were analyzed over a three-night period using a generalized estimating equations (GEE) statistical approach. Associations of overnight changes with measures of sleep were analyzed using GEE. We found significant decreases in white blood cell count (WBC), granulocytes (GRAN), granulocytes% (GRAN%), monocytes (MID), and granulocyte-lymphocyte-ratio. In contrast, lymphocytes% (LYM%) increased significantly and systemic inflammation index showed no difference from post-training to the next morning. Furthermore, there was a significant decrease in WBC and GRAN between morning 1 and morning 3. At morning 4, values returned to baseline (morning 1), irrespective if athletes performed a training session or rested on day 3. Furthermore, sleep duration was significantly and negatively associated with changes in WBC (βz = -0.491) and lymphocytes (βz = -0.451). Our results indicate that overnight sleep duration is an important parameter of immunological overnight regulation for adolescent athletes.

The impact of daytime napping on athletic performance - A narrative review

Mid-day napping has been recommended as a countermeasure against sleep debt and an effective method for recovery, regardless of nocturnal sleep duration. Herein, we summarize the available evidence regarding the influence of napping on exercise and cognitive performance as well as the effects of napping on athletes' perceptual responses prior to or during exercise. The existing studies investigating the influence of napping on athletic performance have revealed equivocal results. Prevailing findings indicate that following a normal sleep night or after a night of sleep loss, a mid-day nap may enhance or restore several exercise and cognitive performance aspects, while concomitantly provide benefits on athletes' perceptual responses. Most, but not all, findings suggest that compared to short-term naps (20-30 min), long-term ones (>35-90 min) appear to provide superior benefits to the athletes. The underlying mechanisms behind athletic performance enhancement following a night of normal sleep or the restoration after a night of sleep loss are not clear yet. However, the absence of benefits or even the deterioration of performance following napping in some studies is likely the result of sleep inertia. The present review sheds light on the predisposing factors that influence the post-nap outcome, such as nocturnal sleep time, mid-day nap duration and the time elapsed between the end of napping and the subsequent testing, discusses practical solutions and stimulates further research on this area.

Acute effect of HIIT on testosterone and cortisol levels in healthy individuals: A systematic review and meta-analysis

To determine the acute effect of a single high-intensity interval training (HIIT) session on testosterone and cortisol levels in healthy individuals, a systematic search of studies was conducted in MEDLINE and Web of Science databases from inception to February 2020. Meta-analyses were performed to establish the acute effect of HIIT on testosterone and cortisol levels immediately after a single HIIT session; after 30 min and 60 min (primary outcomes); and after 120 min, 180 min, and 24 h (secondary outcomes, only for pre-post intervention groups). Potential effect-size modifiers were assessed by meta-regression analyses and analyses of variance. Study quality was assessed using the Cochrane's risk of bias tool and the Physiotherapy Evidence Database scale. The meta-analyses of 10 controlled studies (213 participants) and 50 pre-post intervention groups (677 participants) revealed a significant increase in testosterone immediately after a single HIIT session (d = 0.92 and 0.52, respectively), which disappeared after 30 min (d = 0.18 and -0.04), and returned to baseline values after 60 min (d = -0.37 and -0.16). Significant increases of cortisol were found immediately after (d = 2.17 and 0.64), after 30 min (d = 1.62 and 0.67) and 60 min (d = 1.32 and 0.27). Testosterone and cortisol levels decreased significantly after 120 min (d = -0.48 and -0.95, respectively) and 180 min (d = -0.29 and -1.08), and returned to baseline values after 24 h (d = 0.14 and -0.02). HIIT components and participant's characteristics seem to moderate the effect sizes. In conclusion, testosterone and cortisol increase immediately after a single HIIT session, then drop below baseline levels, and finally return to baseline values after 24 h. This meta-analysis provides a better understanding of the acute endocrine response to a single HIIT session, which would certainly be valuable for both clinicians and coaches in the prescription of exercise programs to improve health and performance. Testosterone and cortisol may be used as sensitive biomarkers to monitor the anabolic and catabolic response to HIIT.

Benefits of Daytime Napping Opportunity on Physical and Cognitive Performances in Physically Active Participants: A Systematic Review

BACKGROUND

Evidence suggests that athletes often experience chronic sleep disturbance. Napping is widely recommended as a safe and non-invasive intervention to counteract the negative effects of partial sleep deprivation. However, systematic reviews on the benefits of napping have yet to be undertaken.

OBJECTIVE

(i) To evaluate the effectiveness of diurnal napping opportunities on athletes' physical and cognitive performance and (ii) to outline how aspects of the study design (i.e., nap duration, exercise protocol, participants' fitness level and previous sleep quantity) can influence the potential effects of napping through a systematic appraisal of the literature.

METHODS

This systematic review was conducted in accordance with the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. PubMed, Web of Science and SCOPUS databases were searched up to June 2020 for relevant studies investigating the effect of napping on physical and cognitive performances in physically active participants. Fourteen strong-quality and four moderate-quality (mean QualSyst score = 75.75 ± 5.7%) studies met our inclusion criteria and were included in the final sample (total participants: 158 physically active and 168 athletes).

RESULTS

Most studies (n = 15) confirmed the beneficial effects of napping and showed that diurnal napping improved short-term physical performance (n = 10), endurance performance (n = 3) and specific skills performance (n = 2). Two studies showed no significant napping effect and only one study showed reduced sprint performance following diurnal napping. Moreover, napping improved reaction time (n = 3), attention (n = 2) and short-term memory (n = 1) performances. Importantly, "replacement naps" improved both physical and cognitive performance regardless of the type of exercise. However, "prophylactic naps" improved only jump, strength, running repeated-sprint, attention and reaction time performances. In addition, this systematic review revealed that longer nap opportunities (i.e., 90 min) resulted in better improvement of physical and cognitive performance and lower induced fatigue.

CONCLUSIONS

A diurnal nap seems to be an advantageous intervention to enhance recovery process and counteract the negative effect of partial sleep deprivation on physical and cognitive performance. Particularly, to optimize physical performances of athletes experiencing chronic lack of sleep, findings from the included individual studies suggest 90 min as the optimal nap duration. Diurnal napping may be beneficial for athletes but this benefit should be viewed with caution due to the quality of the evidence, risk of bias and the limited evidence about napping interventions.

Prevalence of poor sleep quality in athletes before competition

OBJECTIVES

The purpose of this study was to investigate athletes sleep quality before competition and its relationship with age, gender, sport modality, competitive level, competition result, and practice time.

METHODS

The sample was 1010 Brazilian athletes (656 men and 354 women; 511 young and 499 adults), with an age of 20 ± 7 years old. Participants answered the question 'How would you evaluate the quality of your sleep in the past few days?' Participants rated their sleep quality on a Likert-type scale as follows: 1 = very poor, 2 = poor, 3 = regular, 4 = good, 5 = excellent.

RESULTS

Young athletes were 2.30 times more likely to experience poor sleep than adult athletes (p < 0.01; 95% Confidence Interval [CI] = 1.47-3.61). Individual athletes were 3.45 times more likely to present poor sleep compared to athletes of team sports (p = 0.00; 95% CI = 2.18-5.48). International athletes were 1.71 times more likely to present regular sleep compared to regional athletes (p = 0.01; 95% CI = 1.16-2.51). Conclusions: Thus, our study indicates that young, individual sports, and international athletes may be at higher risk of poor sleep quality before competitions.

Listening to motivational music during warming-up attenuates the negative effects of partial sleep deprivation on cognitive and short-term maximal performance: Effect of time of day

This study assessed the effect of time of day (TOD) and listening to music during warm-up on cognitive and physical performances after partial sleep deprivation (PSD) and normal sleep nights (NSN). In a randomized order, twelve male physical education students [mean (SD) age 20.3 ± 2.0 y; BMI 22.90 ± 3.57 kg/m²)] completed a 30-s Wingate test (i.e., mean (MP) and peak powers (PP)), simple (SRT) and choice reaction times (CRT), a mental rotation test (MRT) and a selective attention test. Measurements were performed at 07:00 h and 17:00 h after a NSN and PSD with and without music, with an in-between recovery period of ≥72. Salivary cortisol was measured before and immediately after the Wingate test. Compared to NSN, the results showed that PSD decreased PP (p < .05, d = 0.86) and MP (p < .01, d = 0.86) in the afternoon. However, compared to NSN, listening to music during the warm up after PSD enhanced PP (p < .01, d = 1.40) and MP (p < .05, d = 0.82) in the morning and PP (p < .05, d = 0.78) in the afternoon. Moreover, listening to music lowered post-exercise cortisol in the morning both after NSN (p < .05, d = 0.79) and PSD (p < .05, d = 0.11). After PSD, music reduced the negative mood states (p < .01, d = 0.94), the SRT (p < .05, d = 0.79) and the CRT (p < .05, d = 0.49) in the afternoon. These findings suggest that listening to music during warm-up (i) enhances cognitive and short-term all out performances after NSN and PSD and (ii) partially counteracts sleep-loss-induced degradation of physical and cognitive performances at both TODs.

Melatonin supplementation improves psychomotor and physical performance in collegiate student-athletes following a sleep deprivation night

Several studies report sleep deprivation negatively impacts post-cognitive and physical performance, and other functions. Recent findings indicate ingestion of melatonin prior to exercise enhances tolerance to training and improves competition. We investigated the effects of melatonin supplementation on psychomotor performance and selected physical fitness measures of collegiate student-athletes following 4 h and 24 h of sleep deprivation. The study employed a repeated-measures, double-blind, randomized controlled protocol with posttest control group design with six conditions [3 sleep conditions (without sleep deprivation, 4 h sleep deprivation (4SD) and 24 h sleep deprivation (24SD)) × 2 supplementation conditions (melatonin and placebo)]. Ten trained male collegiate student-athletes (mean ± SD; age: 20 ± 2 y) attended the laboratory on six occasions with 72 h between successive visits. Placebo or 6 mg of melatonin were administered orally in capsules 30 min before the tests of: static and dynamic balance, reaction time, and anaerobic power. Also, blood lactate was measured before and 3 min after the anaerobic power exercise. During the placebo session, the results indicated that 4SD and 24SD had negative effect on the measured parameters, with higher impacts of the 24SD condition. Compared to placebo and during both 4SD and 24SD conditions, melatonin had a positive effect on static and dynamic balance, anaerobic power, blood lactic acid, and reaction time (p < .05). However, 6 mg melatonin ingestion had no significant effect on all dependent variables in collegiate student-athletes after the night without a sleep deprivation (p > .05). In conclusion, 6 mg of melatonin may be used by student-athletes to improve balance and psychomotor and physical performances after 4 h or 24 h of sleep deprivation.

High-Intensity Interval Exercise Performance and Short-Term Metabolic Responses to Overnight-Fasted Acute-Partial Sleep Deprivation

People practicing high-intensity interval exercise (HIIE) fasted during the morning hours under a lack of sleep. Such a habit may jeopardize the health benefits related to HIIE and adequate sleep. Fifteen habitually good sleeper males (age 31.1 ± 5.3 SD year) completed on a treadmill two isocaloric (500 kcal) HIIE sessions (3:2 min work:rest) averaged at 70% VO2reserve after 9-9.5 h of reference sleep exercise (RSE) and after 3-3.5 h of acute-partial sleep deprivation exercise (SSE). Diet and sleep patterns were controlled both 1 week prior and 2 days leading up to RSE and SSE. HIIE related performance and substrate utilization data were obtained from the continuous analysis of respiratory gases. Data were analyzed using repeated measures ANOVA with the baseline maximum oxygen uptake (VO2max) and body fat percentage (BF%) as covariates at p < 0.05. No difference was observed in VO2max, time to complete the HIIE, VE, RER, CHO%, and FAT% utilization during the experimental conditions. Whether attaining an adequate amount of sleep or not, the fasted HIIE performance and metabolism were not affected. We propose to practice the fasted HIIE under adequate sleep to receive the pleiotropic beneficial effects of sleep to the human body.

Effects of partial sleep deprivation after prolonged exercise on metabolic responses and exercise performance on the following day

[Purpose]

We determined the effect of partial sleep deprivation (PSD) after an exercise session on exercise performance on the following morning.

[Methods]

Eleven male athletes performed either a normal sleep trial (CON) or a PSD trial. On the first day (day 1), all subjects performed an exercise session consisting of 90 min of running (at 75% V˙O2max) followed by 100 drop jumps. Maximal strength (MVC) was evaluated before and after exercise. In the CON trial, the sleep duration was 23:00–7:00, while in the PSD trial, the sleep duration was shortened to 40% of the regular sleep duration. On the following morning (day 2), MVC, the metabolic responses during 20 min of running (at 75% V˙O2max), and time to exhaustion (TTE) at 85% V˙O2max were evaluated.

[Results]

On day 2, neither the MVC nor  V˙O2 during 20 min of running differed significantly between the two trials. However, the respiratory exchange ratio was significantly lower in the PSD trial than in the CON trial (p = 0.01). Moreover, the TTE was significantly shorter in the PSD trial than in the CON trial (p = 0.01).

[Conclusion]

A single night of PSD after an exercise session significantly decreased endurance performance without significantly changing muscle strength or cardiopulmonary response.

Second Wave of COVID-19 Global Pandemic and Athletes' Confinement: Recommendations to Better Manage and Optimize the Modified Lifestyle

Coronavirus 2019 (COVID-19) is an infectious viral disease that has spread globally, resulting in the ongoing pandemic. Currently, there is no vaccine or specific treatment for COVID-19. Preventive measures to reduce the chances of contagion consist mainly of confinement, avoiding crowded places, social distancing, masks, and applying strict personal hygiene as recommended by the World Health Organization (WHO). After the first wave of infection in many countries, the potential effects of relaxing containment and physical distancing control measures suggest that as a result of these measures, a second wave of COVID-19 appears probable in these countries. In sport, the period of self-isolation, and quarantine, for COVID-19 affects the physical preparation of athletes as well as their mental health and quality of life to an even greater extent (i.e., nutrition, sleep, healthy lifestyle), and thus, relevant and practical recommendations are needed to help alleviate these physical and mental health concerns. Our review aims to summarize the physiological and psychological effects of detraining associated with athletes' confinement during the proposed second wave of COVID-19. This article also proposes answers to questions that concern the advantages and disadvantages of different types of social media platforms, the importance of nutrition, and the effects of sleep disturbance on the health and modified lifestyle of athletes during this worldwide pandemic. Thus, this review provides some general guidelines to better manage their modified lifestyle and optimally maintain their physical and mental fitness with respect to measures taken during this restrictive proposed second wave of the COVID-19 confinement period.

Concussive head injury exacerbates neuropathology of sleep deprivation: Superior neuroprotection by co-administration of TiO2-nanowired cerebrolysin, alpha-melanocyte-stimulating hormone, and mesenchymal stem cells

Sleep deprivation (SD) is common in military personnel engaged in combat operations leading to brain dysfunction. Military personnel during acute or chronic SD often prone to traumatic brain injury (TBI) indicating the possibility of further exacerbating brain pathology. Several lines of evidence suggest that in both TBI and SD alpha-melanocyte-stimulating hormone (α-MSH) and brain-derived neurotrophic factor (BDNF) levels decreases in plasma and brain. Thus, a possibility exists that exogenous supplement of α-MSH and/or BDNF induces neuroprotection in SD compounded with TBI. In addition, mesenchymal stem cells (MSCs) are very portent in inducing neuroprotection in TBI. We examined the effects of concussive head injury (CHI) in SD on brain pathology. Furthermore, possible neuroprotective effects of α-MSH, MSCs and neurotrophic factors treatment were explored in a rat model of SD and CHI. Rats subjected to 48h SD with CHI exhibited higher leakage of BBB to Evans blue and radioiodine compared to identical SD or CHI alone. Brain pathology was also exacerbated in SD with CHI group as compared to SD or CHI alone together with a significant reduction in α-MSH and BDNF levels in plasma and brain and enhanced level of tumor necrosis factor-alpha (TNF-α). Exogenous administration of α-MSH (250μg/kg) together with MSCs (1×10⁶) and cerebrolysin (a balanced composition of several neurotrophic factors and active peptide fragments) (5mL/kg) significantly induced neuroprotection in SD with CHI. Interestingly, TiO₂ nanowired delivery of α-MSH (100μg), MSCs, and cerebrolysin (2.5mL/kg) induced enhanced neuroprotection with higher levels of α-MSH and BDNF and decreased the TNF-α in SD with CHI. These observations are the first to show that TiO₂ nanowired administration of α-MSH, MSCs and cerebrolysin induces superior neuroprotection following SD in CHI, not reported earlier. The clinical significance of our findings in light of the current literature is discussed.

Effect of Angle of View and Partial Sleep Deprivation on Distance Perception

The present study aimed to investigate the effects of intensive effort on egocentric distance perception according to different angles of view after sleep deprivation at the beginning (SDB) or at the end (SDE) of the night and after a normal sleep night (NNS). Ten male students soccer players (age 22.8 ± 1.3 years; body mass 72.0 ± 10.4 kg; body height 180.0 ± 3.0 cm) performed a repeated cycling (RS) exercise (10 × 6 s maximal cycling with 24 s in between) after SDB, SDE, and NNS. They were asked to estimate three distances (i.e. 15, 25, and 35 m) before and after RS from different angles of view [i.e. in front (0°) and in side (45° left and 45° right)]. For 35 m, distance estimation was better during NNS compared to SDB and SDE for the front and the two side angles either before or after RS (p < 0.05). Concerning 25 m, distance estimation was better after compared to before RS for the front angle during the NNS session (p < 0.05). For 15 m, distance estimation was better during NNS than SDB and SDE for the front and both side angles after RS (p < 0.05). We concluded that partial sleep deprivation negatively affected the estimation of the egocentric distance for the three angles of view either at rest or after RS exercise.

Sleep and Athletic Performance: Impacts on Physical Performance, Mental Performance, Injury Risk and Recovery, and Mental Health

Research has characterized the sleep of elite athletes and attempted to identify factors associated with athletic performance, cognition, health, and mental well-being. Sleep is a fundamental component of performance optimization among elite athletes, yet only recently embraced by sport organizations as an important part of training and recovery. Sleep plays a crucial role in physical and cognitive performance and is an important factor in reducing risk of injury. This article aims to highlight the prevalence of poor sleep, describe its impacts, and address the issue of sport culture surrounding healthy sleep.

Influence Of Narrative Medicine-Based Health Education Combined With An Online Patient Mutual Assistance Group On The Health Of Patients With Inflammatory Bowel Disease and Arthritis

Background

Inflammatory bowel disease arthritis (IBDA) threatens patients' physical and mental health. Therefore, patients need not only physical therapy, but also adequate health education and psychological support. This study was designed to explore the effect of health education based on narrative medicine combined with an online patient mutual assistance group that was based on the physical and mental health of patients with IBDA.

Methods

A total of 120 patients with IBDA were randomly divided into four groups (30 patients per group). Patients in the control group were given routine health education on the premise of routine treatment. The three treatment groups were given health education based on narrative medicine, online patient mutual assistance group intervention, or combined intervention. Depression, sleep, arthralgia, irritable bowel syndrome (IBS) symptoms, and inflammatory factors were measured and compared before and 1 month after the intervention.

Results

Before the intervention, no significant differences were observed in baseline data between the four groups. However, after the intervention, the physical and mental health of patients who received health education based on narrative medicine or online patient mutual assistance groups was improved. Our data showed that patients in the combined intervention group experienced a better outcome.

Conclusion

Narrative medicine-based health education combined with an online patient mutual assistance group is beneficial to the physical and mental health of IBDA patients. Taken together, this model needs to be further deepened and popularized in clinical practice.

Sleep Characteristics and Influencing Factors of Sleep Quality in Patients With Inflammatory Bowel Disease-Peripheral Arthritis

Background: Patients with inflammatory bowel disease-peripheral arthritis (IBD-PA) often accompany by sleep problems, but few studies have used polysomnography to investigate the objective sleep characteristics of IBD-PA.

Methods: Patients in IBD-PA group, inflammatory bowel disease (IBD) group, healthy control (HC) group were examined by polysomnography (PSG) and the sleep characteristics were compared. PSG and Pittsburgh Sleep Quality Scale (PSQI) indices were compared between active and remission IBD-PA patients. The correlation between disease activity and sleep quality in IBD-PA patients was analyzed. The influencing factors of sleep efficiency of IBD-PA patients were analyzed.

Results: The total sleep time (TST), rapid-eye-movement sleep (REM) time, slow wave sleep (S3 + S4) and sleep efficiency (SE) in the IBD-PA group were significantly less than those in the HC group and IBD group (P < 0.05), while the number and time of wake after sleep onset (WASO) and sleep latency (SL) were significantly longer than those in the HC group and IBD group (P < 0.05). To IBD-PA patients, the disease activity was negatively related to sleep quality. There was a significant difference in SE, the number of WASO, S1, S3+S4 of PSG, as well as the PSQI total score between active and remission patients. Abdominal pain, joint pain, depression, and C-reactive protein were the influencing factors of sleep efficiency.

Conclusions: The sleep quality of patients with IBD was poor than the control group, and that of patients with IBD-PA was even worse. Therefore, sleep management should be included in IBD management.

Observing Ramadan and sleep-wake patterns in athletes: a systematic review, meta-analysis and meta-regression

Objective

To evaluate the effect of observing Ramadan on athletes’ sleep patterns.

Design

Systematic review and meta-analysis.

Data sources

The entire content of PubMed/MEDLINE and Web of Science.

Eligibility criteria for selecting studies

Single-group, prepost and cross-over design studies conducted in athletes aged ≥18 years, training at least twice a week and published in English before 12 July 2018 were included. Studies assessing sleep quantity, quality, daytime sleepiness and/or daily naps based on objective or subjective methods were deemed eligible.

Study appraisal

The methodological quality was assessed using ‘QualSyst’.

Results

Of 13 selected articles, 7 were of strong quality, 3 were moderate and 3 were weak. 11 studies evaluated total sleep time (TST); this decreased during Ramadan in 4 studies, increased in 1 and remained unchanged in 6. Pooled TST findings indicated a moderate effect size (− 0.97, SE=0.37, 95% CI −1.69 to −0.25, t=−2.64, p=0.01) with significant heterogeneity but no publication bias. Meta-regressions showed no effects of study year, age, sample size, type of sport or competition level, but there were effects of country (with France and Tunisia being the most affected countries and Turkey the least affected, Q=32.14, p<0.0001) and study design (Q=7.74, p=0.02). Four studies measured self-reported sleep quality and it decreased in three studies. One study of sleep architecture reported more frequent waking and more light sleep during Ramadan. Daily nap duration was increased in two studies, but daytime sleepiness remained unchanged in four studies.

Conclusion

When athletes continue to train at least two times/week while observing Ramadan, TST is decreased compared with athletes’ baseline levels.

Sleep deprivation affects post-lunch dip performances, biomarkers of muscle damage and antioxidant status

To compare the effects of two types of partial sleep deprivation (PSD) at the beginning (PSDBN) and the end (PSDEN) of the night on mood, cognitive performances, biomarkers of muscle damage, haematological status and antioxidant responses before and after repeated-sprint exercise in the post-lunch dip. Fourteen male athletes performed the Running-based Anaerobic Sprint Test following: (i) baseline normal sleep night, (ii) PSDBN, or (iii) PSDEN in a randomized and counter-balanced order. During each condition, participants performed simple and choice reaction time tests, the Profile of Mood States, subjective sleepiness, and the Running-based Anaerobic Sprint Test. Plasma biomarkers of muscle damage, total blood count, and antioxidant activities were measured at rest and after the repeated sprint in the three conditions. PSDEN decreased Pmax (p=0.008; d=1.12), Pmean (p=0.002; d=1.33) and Pmin (p=0.006; d=1.15), whilst PSDBN decreased Pmean (p=0.04; d=0.68) and Pmin (p=0.028; d=0.58), in comparison with baseline. PSDEN exerted stronger effects on Pmax (p=0.013; d=0.74) and Pmean (p=0.048; d=0.54) than PSDBN. Moreover, PSDEN increased subjective sleepiness (p<0.001; d=1.93), while PSDBN impaired choice reaction time (p<0.001, d=1.89). Both PSD types decreased resting glutathione peroxidase (p<0.001; d=5.43, d=3.86), and increased aspartate amino-transferase levels (p<0.001; d=1.36, d=1.37) respectively for PSDEN and PSDBN. PSDEN decreased repeated-sprint performances more than PSDBN in the post-lunch dip. This could be explained by the lowered mood and resting antioxidant status and the increased inflammatory profile after PSDEN. Repeated-sprint exercise resulted in greater inflammation after PSDEN, despite the decreased physical performance. The drop of resting antioxidant defence and haemoglobin concentration after PSDEN could explain the increased sleep drive at the post-lunch dip.

Fire service instructors' working practices: A UK survey

Analysis of Fire Service Instructors (FSI) working practices and health is needed to minimise health risks related to heat illness, cardiovascular events and immunological stress. Online surveys were distributed to UK FSI and Firefighters (FF). One hundred and thirty FSI (age: 43 ± 7yrs) and 232 FF (age: 41 ± 8yrs) responded. FSI experienced 2-10 live fires per week, with 45% of FSI reporting management does not set a limit on the number of exposures. Few FSI followed hydration guidelines, or cooling methods. New symptoms of ill health were reported by 41% of FSI and 21% of FF. FSI with ≥11 Breathing Apparatus exposures per month were 4.5 times (95% CI 1.33-15.09) more likely to experience new symptoms. A large proportion of FSI are experiencing new symptoms of illness after starting their career, and guidelines on exposure and hydration are not universally in place to reduce the risk of future health problems.

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.

Blood-Brain Barrier Disruption Induced by Chronic Sleep Loss: Low-Grade Inflammation May Be the Link

Sleep is a vital phenomenon related to immunomodulation at the central and peripheral level. Sleep deficient in duration and/or quality is a common problem in the modern society and is considered a risk factor to develop neurodegenerative diseases. Sleep loss in rodents induces blood-brain barrier disruption and the underlying mechanism is still unknown. Several reports indicate that sleep loss induces a systemic low-grade inflammation characterized by the release of several molecules, such as cytokines, chemokines, and acute-phase proteins; all of them may promote changes in cellular components of the blood-brain barrier, particularly on brain endothelial cells. In the present review we discuss the role of inflammatory mediators that increase during sleep loss and their association with general disturbances in peripheral endothelium and epithelium and how those inflammatory mediators may alter the blood-brain barrier. Finally, this manuscript proposes a hypothetical mechanism by which sleep loss may induce blood-brain barrier disruption, emphasizing the regulatory effect of inflammatory molecules on tight junction proteins.

Chronic occupational exposures can influence the rate of PTSD and depressive disorders in first responders and military personnel

BACKGROUND

First responders and military personnel experience rates of post-traumatic stress disorder (PTSD) far in excess of the general population. Although exposure to acute traumatic events plays a role in the genesis of these disorders, in this review, we present an argument that the occupational and environmental conditions where these workers operate are also likely contributors.

PRESENTATION OF THE HYPOTHESIS

First responders and military personnel face occupational exposures that have been associated with altered immune and inflammatory activity. In turn, these physiological responses are linked to altered moods and feelings of well-being which may provide priming conditions that compromise individual resilience, and increase the risk of PTSD and depression when subsequently exposed to acute traumatic events. These exposures include heat, smoke, and sleep restriction, and physical injury often alongside heavy physical exertion. Provided the stimulus is sufficient, these exposures have been linked to inflammatory activity and modification of the hypothalamic-pituitary axis (HPA), offering a mechanism for the high rates of PTSD and depressive disorders in these occupations.

TESTING THE HYPOTHESIS

To test this hypothesis in the future, a case-control approach is suggested that compares individuals with PTSD or depressive disorders with healthy colleagues in a retrospective framework. This approach should characterise the relationships between altered immune and inflammatory activity and health outcomes. Wearable technology, surveys, and formal experimentation in the field will add useful data to these investigations.

IMPLICATIONS OF THE HYPOTHESIS

Inflammatory changes, linked with occupational exposures in first responders and military personnel, would highlight the need for a risk management approach to work places. Risk management strategies could focus on reducing exposure, ensuring recovery, and increasing resilience to these risk contributors to minimise the rates of PTSD and depressive disorders in vulnerable occupations.

Relationships between inflammatory cytokine and cortisol responses in firefighters exposed to simulated wildfire suppression work and sleep restriction

The interplay between inflammatory and cortisol responses modulates an appropriate response to a stressor. Exposure to severe stressors, however, may alter the actions and relationships of these responses and contribute to negative health outcomes. Physical work and sleep restriction are two stressors faced by wildland firefighters, yet their influence on the relationship between inflammatory and cortisol responses is unknown. The aim of the present study was to quantify the relationship between the cytokine and cortisol responses to sleep restriction while performing simulated physical wildfire suppression work. Firefighters completed 3 days of simulated physical firefighting work separated by either an 8-h (Control condition; n = 18) or 4-h sleep (Sleep restriction condition; n = 17) opportunity on each of the two nights. Salivary cortisol and inflammatory cytokines (IL-6, IL-8, IL-1β, TNF-α, IL-4, and IL-10) were measured throughout each day. An increase in morning IL-6 was related to a rise (6.2%, P = 0.043) in evening cortisol among firefighters in the sleep restriction condition. Higher morning IL-6 levels were related to increased (5.3%, P = 0.048) daily cortisol levels, but this relationship was not different between conditions. Less pronounced relationships were demonstrated between TNF-α, IL-10, IL-4, and cortisol independent of the sleep opportunity, but relationships did not persist after adjusting for demographic factors and other cytokines. These findings quantify the relationship between cytokine and cortisol responses among wildland firefighters exposed to simulated occupational stressors. Potential disturbances to the IL-6 and cortisol relationship among sleep-restricted firefighters’ supports further investigations into the negative health effects related to possible imbalances between these systems.

Sleep-disordered breathing in patients with post-traumatic stress disorder

Post-traumatic stress disorder (PTSD) and sleep-disordered breathing (SDB) are shared by many patients. They both affect sleep and the quality of life of affected subjects. A critical review of the literature supports an association between the two disorders in both combat-related and non-combat-related PTSD. The exact mechanism linking PTSD and SDB is not fully understood. A complex interplay between sleep fragmentation and neuroendocrine pathways is suggested. The overlap of symptoms between PTSD and SDB raises diagnostic challenges that may require a novel approach in the methods used to diagnose the coexisting disorders. Similar therapeutic challenges face patients and providers when treating concomitant PTSD and SDB. Although continuous positive airway pressure therapy imparts a mitigating effect on PTSD symptomatology, lack of both acceptance and adherence are common. Future research should focus on ways to improve adherence to continuous positive airway pressure therapy and on the use of alternative therapeutic methods for treating SDB in patients with PTSD.

The Impact of Sleep Restriction and Simulated Physical Firefighting Work on Acute Inflammatory Stress Responses

OBJECTIVES

This study investigated the effect restricted sleep has on wildland firefighters' acute cytokine levels during 3 days and 2 nights of simulated physical wildfire suppression work.

METHODS

Firefighters completed multiple days of physical firefighting work separated by either an 8-h (Control condition; n = 18) or 4-h (Sleep restriction condition; n = 17) sleep opportunity each night. Blood samples were collected 4 times a day (i.e., 06:15, 11:30, 18:15, 21:30) from which plasma cytokine levels (IL-6, IL-8, IL-1β, TNF-α, IL-4, IL-10) were measured.

RESULTS

The primary findings for cytokine levels revealed a fixed effect for condition that showed higher IL-8 levels among firefighters who received an 8-h sleep each night. An interaction effect demonstrated differing increases in IL-6 over successive days of work for the SR and CON conditions. Fixed effects for time indicated that IL-6 and IL-4 levels increased, while IL-1β, TNF-α and IL-8 levels decreased. There were no significant effects for IL-10 observed.

CONCLUSION

Findings demonstrate increased IL-8 levels among firefighters who received an 8-h sleep when compared to those who had a restricted 4-h sleep. Firefighters' IL-6 levels increased in both conditions which may indicate that a 4-h sleep restriction duration and/or period (i.e., 2 nights) was not a significant enough stressor to affect this cytokine. Considering the immunomodulatory properties of IL-6 and IL-4 that inhibit pro-inflammatory cytokines, the rise in IL-6 and IL-4, independent of increases in IL-1β and TNF-α, could indicate a non-damaging response to the stress of simulated physical firefighting work. However, given the link between chronically elevated cytokine levels and several diseases, further research is needed to determine if firefighters' IL-8 and IL-6 levels are elevated following repeated firefighting deployments across a fire season and over multiple fire seasons.

Sleep and athletic performance: the effects of sleep loss on exercise performance, and physiological and cognitive responses to exercise

Although its true function remains unclear, sleep is considered critical to human physiological and cognitive function. Equally, since sleep loss is a common occurrence prior to competition in athletes, this could significantly impact upon their athletic performance. Much of the previous research has reported that exercise performance is negatively affected following sleep loss; however, conflicting findings mean that the extent, influence, and mechanisms of sleep loss affecting exercise performance remain uncertain. For instance, research indicates some maximal physical efforts and gross motor performances can be maintained. In comparison, the few published studies investigating the effect of sleep loss on performance in athletes report a reduction in sport-specific performance. The effects of sleep loss on physiological responses to exercise also remain equivocal; however, it appears a reduction in sleep quality and quantity could result in an autonomic nervous system imbalance, simulating symptoms of the overtraining syndrome. Additionally, increases in pro-inflammatory cytokines following sleep loss could promote immune system dysfunction. Of further concern, numerous studies investigating the effects of sleep loss on cognitive function report slower and less accurate cognitive performance. Based on this context, this review aims to evaluate the importance and prevalence of sleep in athletes and summarises the effects of sleep loss (restriction and deprivation) on exercise performance, and physiological and cognitive responses to exercise. Given the equivocal understanding of sleep and athletic performance outcomes, further research and consideration is required to obtain a greater knowledge of the interaction between sleep and performance.

High C-Reactive Protein Is Associated with Poor Sleep Quality Independent of Nocturnal Symptoms in Patients with Inflammatory Bowel Disease

BACKGROUND

Sleep disruption is common in inflammatory bowel diseases (IBD). However, studies demonstrating a similar prevalence in irritable bowel syndrome suggest that nighttime disruption due to diarrhea and abdominal pain may be key drivers of poor sleep quality. Whether inflammation is associated with poor sleep independently has not been examined previously.

METHODS

This single-center study included subjects with IBD recruited to an ongoing prospective registry who completed a questionnaire assessing sleep quality and mood. Inflammatory marker levels [C-reactive protein (CRP), erythrocyte sedimentation rate] and clinical disease activity including nighttime disruption on the day of enrollment were obtained from the medical record. Logistic regression models were used to identify predictors of sleep quality.

RESULTS

The study included 131 subjects (72 women) with a median age of IBD diagnosis of 25 years. Twenty-three subjects (19 %) had a high C-reactive protein level (≥8 mg/dL). Poor sleep was more common in those with high CRP levels than with normal values (70 vs. 39 %, p = 0.009). This association remained significant on multivariate analysis [Odds ratio (OR) 4.12, 95 % confidence interval (CI) 1.38-12.29]. Adjusting for the presence of nighttime disruption did not significant alter this association (OR 3.16, 95 % CI 1.01-9.90). High CRP correlated with poor sleep even in patients not experiencing nocturnal symptoms (n = 101, OR 4.89, 95 % CI 1.24-19.36).

CONCLUSION

High CRP is associated with poor sleep quality in IBD independent of the presence of nighttime disruptions, suggesting that a relationship exists between circulating inflammatory markers and sleep.

Caloric Restriction Effect on Proinflammatory Cytokines, Growth Hormone, and Steroid Hormone Concentrations during Exercise in Judokas

The aim of this study was to evaluate the effect of caloric restriction on the immune and hormonal responses during exercise in judo athletes. In a randomised order, 11 male judokas (age: 20.45 ± 0.51; height: 1.71 ± 0.3 m; and body weight: 75.9 ± 3.1 kg) participate in this study during a period of weight maintenance (baseline) and after 7 days of caloric restriction (CR). All subjects performed the Special Judo Fitness Test (SJFT) during the two conditions. Values for nutrient intakes were obtained from a 7 d food record kept during a period of weight maintenance and after a 7-day food restriction (−5~6 MJ/day). Our results showed that CR resulted in significant decreases in body weight (P < 0.05) and performance (P < 0.05). However, heart rate and SJFT index (P < 0.05) increase significantly during CR in comparison to baseline. Moreover, exercise leads to a significant increase in testosterone, cortisol, growth hormone (GH), leukocytes, neutrophils, TNF-α, and IL-6, in both CR and baseline conditions. Compared to baseline, TNF-α and IL-6 were significantly higher during CR condition (P < 0.05). Additionally, CR leads to an increase in cortisol and GH (P < 0.05) and a decrease in testosterone concentrations (P < 0.05).

Sleep duration affects risk for ulcerative colitis: a prospective cohort study

BACKGROUND & AIMS

Sleep deprivation is associated with production of inflammatory cytokines. Disturbed sleep quality has been associated with increased risk of disease flare in patients with Crohn's disease (CD) or ulcerative colitis (UC). However, the association between sleep and risk of incident CD and UC has not been previously examined.

METHODS

We conducted a prospective study of women who were enrolled in the Nurses' Health Study (NHS) I since 1976 and NHS II since 1989 and followed through detailed biennial questionnaires with >90% follow-up. We examined the association of sleep duration reported in 1986 in NHS I and 2001 in NHS II with incident CD and UC, diagnosed through 2010, in NHS I and 2009 in NHS II. Cox proportional hazards models adjusting for potential confounders were used to calculate hazard ratios and 95% confidence intervals (CIs).

RESULTS

Among 151,871 women, we confirmed 191 cases of CD (incidence, 8/100,000 person-years) and 230 cases of UC (incidence, 10/100,000 person-years) over 2,292,849 person-years. Compared with women with reported usual sleep durations of 7-8 h/day (incidence, 8/100,000 person-years), women with reported sleep duration <6 h/day (11/100,000 person-years) or >9 h/day (20/100,000 person-years) had a higher incidence of UC (P < .05). The multivariate hazard ratios for UC were 1.51 (95% CI, 1.10-2.09) for sleep durations <6 h/day and 2.05 (95% CI, 1.44-2.92) for sleep durations >9 h/day, compared with sleep durations of 7-8 h/day. In contrast, sleep duration did not modify risk of CD. Duration of rotating night shift work was not associated with CD or UC.

CONCLUSIONS

On the basis of data from the NHS I and II, less than 6 hours sleep/day and more than 9 hours sleep/day are each associated with an increased risk of UC. Further studies are needed to evaluate sleep as a modifiable risk factor in the pathogenesis and progression of IBD.

Exercise-Induced growth hormone during acute sleep deprivation

The effect of acute (24‐h) sleep deprivation on exercise‐induced growth hormone (GH) and insulin‐like growth factor‐1 (IGF‐1) was examined. Ten men (20.6 ± 1.4 years) completed two randomized 24‐h sessions including a brief, high‐intensity exercise bout following either a night of sleep (SLEEP) or (24‐h) sleep deprivation (SLD). Anaerobic performance (mean power [MP], peak power [PP], minimum power [MinP], time to peak power [TTPP], fatigue index, [FI]) and total work per sprint [TWPS]) was determined from four maximal 30‐sec Wingate sprints on a cycle ergometer. Self‐reported sleep 7 days prior to each session was similar between SLEEP and SLD sessions (7.92 ± 0.33 vs. 7.98 ± 0.39 h, P =0.656, respectively) and during the actual SLEEP session in the lab, the total amount of sleep was similar to the 7 days leading up to the lab session (7.72 ± 0.14 h vs. 7.92 ± 0.33 h, respectively) (P =0.166). No differences existed in MP, PP, MinP, TTPP, FI, TWPS, resting GH concentrations, time to reach exercise‐induced peak GH concentration (TTP), or free IGF‐1 between sessions. GH area under the curve (AUC) (825.0 ± 199.8 vs. 2212.9 ± 441.9 μg/L*min, P <0.01), exercise‐induced peak GH concentration (17.8 ± 3.7 vs. 39.6 ± 7.1 μg/L, P <0.01) and ΔGH (peak GH – resting GH) (17.2 ± 3.7 vs. 38.2 ± 7.3 μg/L, P <0.01) were significantly lower during the SLEEP versus SLD session. Our results indicate that the exercise‐induced GH response was significantly augmented in sleep‐deprived individuals.

Human growth hormone release is heavily influenced by sleep and exercise. Our study shows that sleep deprivation dramatically augments the exercise‐induced human growth hormone response.

Low-level mercury in children: associations with sleep duration and cytokines TNF-α and IL-6

There is a sizeable literature suggesting that mercury (Hg) exposure affects cytokine levels in humans. In addition to their signaling role in the immune system, some cytokines are also integrally associated with sleep behavior. In this cross-sectional study of 9-11 year old children (N=100), we measured total blood Hg in whole blood, serum levels of tumor necrosis factor α (TNF-α) and interleukin 6 (IL-6), and objectively measured sleep and activity using actigraphy. Increasing blood Hg was associated with significantly shorter sleep duration and lower levels of TNF-α. IL-6 was not associated with sleep or blood Hg. This study is the first to document an association between total blood Hg and sleep (albeit a small effect), and the first to consider the associations of total blood Hg with cytokines TNF-α and IL-6 in a pediatric sample. Further research using alternative designs (e.g., time-series) is necessary to determine if there is a causal pathway linking low-level Hg exposure to sleep restriction and reduced cytokines.

Sleep and exercise: a reciprocal issue?

Sleep and exercise influence each other through complex, bilateral interactions that involve multiple physiological and psychological pathways. Physical activity is usually considered as beneficial in aiding sleep although this link may be subject to multiple moderating factors such as sex, age, fitness level, sleep quality and the characteristics of the exercise (intensity, duration, time of day, environment). It is therefore vital to improve knowledge in fundamental physiology in order to understand the benefits of exercise on the quantity and quality of sleep in healthy subjects and patients. Conversely, sleep disturbances could also impair a person's cognitive performance or their capacity for exercise and increase the risk of exercise-induced injuries either during extreme and/or prolonged exercise or during team sports. This review aims to describe the reciprocal fundamental physiological effects linking sleep and exercise in order to improve the pertinent use of exercise in sleep medicine and prevent sleep disorders in sportsmen.