Effects of 29-h total sleep deprivation on local cold tolerance in humans

The impact of sleep disturbance on pain perception: A systematic review examining the moderating effect of sex and age

Females have increased pain sensitivity and are more vulnerable to chronic pain conditions. Sleep disturbances are comorbid with chronic pain and exacerbate pain symptoms. Different types of sleep disturbance affect pain perception distinctly, but it is not clear if these effects are equal in men and women. This systematic review investigated potential differences in how sleep disturbance affects pain in males and females. We searched EBSCO, MEDLINE, Psych INFO, Science Direct, and Web of Science from January 2001 to November 2022 and found 38 studies with 978 participants. Separate random-effects models were used to estimate the pooled effect sizes based on standardized mean differences (SMDs) of experimental sleep disturbance paradigms on various pain outcomes. Sex moderated the effect of sleep disturbance on pain facilitation (SMD = 0.13; 95%CI: 0.004 to 0.022; p=.009) and pain inhibition (SMD = 0.033; 95%CI: 0.011 to 0.054; p=.005), with increased facilitation and decreased inhibition in females, but the opposite effect in males. Further, age moderated the effects of total sleep deprivation (SMD = -0.194; 95%CI -0.328 to -0.060; p=.008) on pain sensitivity and fragmented sleep (SMD = -0.110; 95%CI: 0.148 to -0.072; p<.001) on pain threshold. While the moderating effect of sex and age on the sleep-pain relationship was small, these factors need to be considered in future sleep-pain research.

Short-term sleep deprivation and human thermoregulatory function during thermal challenges

NEW FINDINGS

What is the topic of this review? It is generally accepted that sleep deprivation constitutes a predisposing factor to the development of thermal injury. This review summarizes the available human-based evidence on the impact of sleep loss on autonomic and behavioural thermoeffectors during acute exposure to low and high ambient temperatures. What advances does it highlight? Limited to moderate evidence suggests that sleep deprivation per se impairs thermoregulatory defence mechanisms during exposure to thermal extremes. Future research is required to establish whether inadequate sleep enhances the risk for cold- and heat-related illnesses.

ABSTRACT

Relatively short periods of inadequate sleep provoke physiological and psychological perturbations, typically leading to functional impairments and degradation in performance. It is commonly accepted that sleep deprivation also disturbs thermal homeostasis, plausibly enhancing susceptibility to cold- and heat-related illnesses. Herein, we summarize the current state of human-based evidence on the impact of short-term (i.e., ≤4 nights) sleep deprivation on autonomic and behavioural thermoeffectors during acute exposure to low and high ambient temperatures. The purpose of this brief narrative review is to highlight knowledge gaps in the area and stimulate future research to investigate whether sleep deprivation constitutes a predisposing factor for the development of thermal injuries.

Effects of sleep deprivation on endothelial function in adult humans: a systematic review

Sleep deprivation is highly prevalent and is associated with increased cardiovascular disease (CVD) morbidity and mortality. Age-related alterations in sleep and chronobiology may exaggerate CVD susceptibility in older individuals. The mechanisms responsible for the association between sleep deprivation and CVD are not fully understood, but endothelial dysfunction may play a central role. Our objective was to conduct a systematic literature review to evaluate the evidence on the effects of sleep deprivation on endothelial function (EF). This review adhered to the PRISMA guidelines and was pre-registered with PROSPERO (#CRD42020192485, 07/24/2020). We searched PubMed, Web of Science, Embase, and Cochrane Library for articles published through May 1, 2020. Eligibility criteria included publication in English and use of well-established EF methodologies in adult humans. Two investigators independently performed the literature search, study selection, data extraction, risk-of-bias assessment, and qualitative data synthesis. Out of 3571 articles identified, 24 articles were included in the systematic review. Main findings include the following: (1) shorter sleep duration is associated with lower macrovascular EF; (2) not sleeping 7-9 h/night is linked with impaired microvascular EF; (3) sleep restriction impairs micro- and macrovascular EF; (4) acute total sleep deprivation impairs micro- and macrovascular EF but data on macrovascular EF are less consistent; and (5) shift work impairs macrovascular EF. In conclusion, sleep deprivation impairs EF, which may explain the link between insufficient sleep and CVD. Future investigations should fully elucidate the underlying mechanisms and develop strategies to combat the adverse endothelial effects of sleep deprivation across the lifespan.

Acute partial sleep deprivation and high-intensity interval exercise effects on postprandial endothelial function

PURPOSE

Acute-total and chronic-partial sleep deprivation increase the risks for cardiovascular disease (CVD). Cardiovascular function assessed by flow mediated dilation (FMD) is reduced after sleep deprivation. High-intensity interval exercise (HIIE) improves postprandial FMD. Sleep-deprived individuals may practice HIIE followed by a high-fat breakfast. This study investigated the acute-partial sleep deprivation (APSD) and HIIE interaction on postprandial FMD.

METHODS

Fifteen healthy males (age 31 ± 5 years) participated in: (a) reference sleep (~ 9.5 h) with no HIIE (RS), (b) RS and HIIE (RSX), and (c) APSD and HIIE (SSX). HIIE was performed in 3:2 min intervals at 90% and 40% of VO₂ reserve. FMD was assessed the night before (D1), the morning of the next day (D2), 1 h (1hrPE) and 4 h post HIIE (4hrPE).

RESULTS

FMD% change was lower at RS compared to both RSX (F_1,14 = 23.96, p < 0.001, η² = 0.631) and SSX (F_1,14 = 4.8, p = 0.47, η² = 0.253) at 1hrPE. RSX and SSX did not differ at 1hrPE (F_1,14 = 0.2, p = 0.889, η² = 0.001), but SSX elicited greater FDM responses. Absolute FMD change was lower at RS compared to both RSX (F_1,14 = 21.5, p < 0.001, η² = 0.606) and SSX (F_1,14 = 7.01, p = 0.019, η² = 0.336) at 1hrPE. RSX and SSX did not differ at 1hrPE (F_1,14 = .03, p = 0.858, η² = 0.002), but SSX elicited greater FDM responses.

CONCLUSIONS

HIIE short-term effects on cardiovascular function remain cardioprotective even after an acute-partial sleep deprivation.

The effect of sleep deprivation on pain perception in healthy subjects: a meta-analysis

BACKGROUND

There is strong evidence indicating an interaction between sleep and pain. However, the size of this effect, as well as the clinical relevance, is unclear. Therefore, this meta-analysis was conducted to quantify the effect of sleep deprivation on pain perception.

METHODS

A systematic literature search was conducted using the electronic databases PubMed, Cochrane, Psyndex, Psycinfo, and Scopus. By conducting a random-effect model, the pooled standardized mean differences (SMDs) of sleep deprivation on pain perception was calculated. Studies that investigated any kind of sleep deprivation in conjunction with a pain measurement were included. In cases of several pain measurements within a study, the average effect size of all measures was calculated.

RESULTS

Five eligible studies (N = 190) for the between-group analysis and ten studies (N = 266) for the within-group analysis were identified. Sleep deprivation showed a medium effect in the between-group analysis (SMD = 0.62; CI95: 0.12, 1.12; z = 2.43; p = 0.015) and a large effect in the within-group analysis (SMD = 1.49; CI95: 0.82, 2.17; z = 4.35; p <0.0001). The test for heterogeneity was not significant in the between-group analysis (Q = 5.29; df = 4; p = 0.2584), but it was significant in the within-group analysis (Q = 53.49; df = 9; p <0.0001).

CONCLUSION

This meta-analysis confirms a medium effect (SMD = 0.62) of sleep deprivation on pain perception. As this meta-analysis is based on experimental studies in healthy subjects, the clinical relevance should be clarified.

Vascular response to 1 week of sleep restriction in healthy subjects. A metabolic response?

BACKGROUND

Sleep loss may induce endothelial dysfunction, a key factor in cardiovascular risk. We examined the endothelial function during one week of sleep restriction and a recovery period (from 3-to-13 days) in healthy subjects, and its link to autonomic, inflammatory and/or endocrine responses.

METHODS

12 men were followed at baseline (B1, 8-h sleep), after 2 (SR2) and 6 (SR6) days of SR (4-h sleep: 02:00-06:00) and after 1 (R1) and 12 (R12) recovery nights (8h sleep). At 10:00, we assessed changes in: arm cutaneous vascular conductance (CVC) induced by local application of methacholine (MCh), cathodal current (CIV) and heat (44°C), finger CVC and skin temperature (Tfi) during local cold exposure (5°C, 20-min) and passive recovery (22°C, 20-min). Blood samples were collected at 08:00.

RESULTS

Compared with baseline (B1), MCh and heat-induced maximal CVC values (CVC peak) were decreased at SR6 and R1. No effect of SR was observed for Tfi and CVC during immersion whereas these values were lower during passive recovery on SR6 and R1. From SR2 to R12, plasma concentrations of insulin, IGF-1 (total and free) and MCP-1 were significantly increased while those of testosterone and prolactin were decreased. Whole-blood blood mRNA concentrations of TNF-α and IL-1β were higher than B1. No changes in noradrenaline concentrations, heart rate and blood pressure were observed.

CONCLUSIONS

These results demonstrate that SR reduces endothelial-dependent vasodilatation and local tolerance to cold. This endothelial dysfunction is independent of blood pressure and sympathetic activity but associated with inflammatory and metabolic pathway responses (ClinicalTrials-NCT01989741).

Napping reverses increased pain sensitivity due to sleep restriction

Study Objective

To investigate pain sensitivity after sleep restriction and the restorative effect of napping.

Design

A strictly controlled randomized crossover study with continuous polysomnography monitoring was performed.

Setting

Laboratory-based study.

Participants

11 healthy male volunteers.

Interventions

Volunteers attended two three-day sessions: “sleep restriction” alone and “sleep restriction and nap”. Each session involved a baseline night of normal sleep, a night of sleep deprivation and a night of free recovery sleep. Participants were allowed to sleep only from 02:00 to 04:00 during the sleep deprivation night. During the “sleep restriction and nap” session, volunteers took two 30-minute naps, one in the morning and one in the afternoon.

Measurements and Results

Quantitative sensory testing was performed with heat, cold and pressure, at 10:00 and 16:00, on three areas: the supraspinatus, lower back and thigh. After sleep restriction, quantitative sensory testing revealed differential changes in pain stimuli thresholds, but not in thermal threshold detection: lower back heat pain threshold decreased, pressure pain threshold increased in the supraspinatus area and no change was observed for the thigh. Napping restored responses to heat pain stimuli in the lower back and to pressure stimuli in the supraspinatus area.

Conclusions

Sleep restriction induces different types of hypersensitivity to pain stimuli in different body areas, consistent with multilevel mechanisms, these changes being reversed by napping. The napping restorative effect on pain thresholds result principally from effects on pain mechanisms, since it was independent of vigilance status.

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.

Total sleep deprivation alters endothelial function in rats: a nonsympathetic mechanism

STUDY OBJECTIVES

Sleep loss is suspected to induce endothelial dysfunction, a key factor in cardiovascular risk. We examined whether sympathetic activity is involved in the endothelial dysfunction caused by total sleep deprivation (TSD).

DESIGN

TWO GROUPS: TSD (24-h wakefulness), using slowly rotating wheels, and wheel control (WC).

PARTICIPANTS

Seven-month-old male Wistar rats.

INTERVENTIONS

Pharmacological sympathectomy (reserpine, 5 mg/kg, intraperitoneal), nitric oxide synthase (NOS) inhibition (N (G)-nitro-L-arginine, 20 mg/kg, intraperitoneally 30 min before experiment) and cyclooxygenase (COX) inhibition (indomethacin, 5 mg/kg, intraperitoneally 30 min before experiment).

MEASUREMENTS AND RESULTS

In protocol 1, changes in heart rate (HR) and blood pressure were continuously recorded in the sympathectomized and non-sympathectomized rats. Blood pressure and HR increased during TSD in non-sympathectomized rats. In protocol 2, changes in skin blood flow (vasodilation) were assessed in the sympathectomized and non-sympathectomized rats using laser-Doppler flowmetry coupled with iontophoretic delivery of acetylcholine (ACh), sodium nitroprusside (SNP), and anodal and cathodal currents. ACh- and cathodal current-induced vasodilations were significantly attenuated after TSD in non-sympathectomized and sympathectomized rats (51% and 60%, respectively). In protocol 3, ACh-induced vasodilation was attenuated after NOS and COX inhibition (66% and 49%, respectively). Cathodal current-induced vasodilation decreased by 40% after COX inhibition. In TSD compared to WC a decrease in ACh-induced vasodilation was still observed after COX inhibition. No changes in SNP- and anodal current-induced vasodilation were detected.

CONCLUSION

These results demonstrate that total sleep deprivation induces a reduction in endothelial-dependent vasodilation. This endothelial dysfunction is independent of blood pressure and sympathetic activity but associated with nitric oxide synthase and cyclooxygenase pathway alterations.