Perception versus Reality: The Relationship between Subjective and Objective Measures of Sleep When On-call under Simulated Laboratory Conditions.

BACKGROUND: On-call working arrangements have been shown to negatively impact sleep. However, workers may perceive their sleep to be worse than it actually is. The aim of this study was to compare participants' pre- and post-sleep estimates of sleep duration and sleep quality with objectively measured sleep when on-call under laboratory conditions. PARTICIPANTS: 72 healthy, adult males. METHODS: Analyses were performed on three interrelated studies, all of which consisted of four nights in a sleep laboratory. Following adaptation and baseline nights were two on-call nights (sleep opportunity 23:00 h - 07:00 h). Before and after each sleep opportunity, participants provided subjective estimates of sleep. Sleep was objectively measured using polysomnography. RESULTS: Estimated sleep duration (6.74 ± 1.13 h) and sleep onset latency (20.55 ± 14.85 min) were significantly poorer than objectively measured sleep outcomes (sleep duration 7.21 ± 1.25 h; sleep latency 13.20 ± 10.06 min). Of the variance in post-sleep estimated sleep duration, 14% was associated with objectively measured minutes of N3 (R2Δ = 0.55) and REM (R2Δ = 0.75). Additionally, 14% of post-sleep sleep quality estimation variance was associated with minutes of N2 (R2Δ = 0.60) and N3 (R2Δ = 0.79), measured by polysomnography. CONCLUSIONS: Some objective measures of sleep were associated with subjective estimates of sleep duration and sleep quality. However, individuals may overestimate sleep onset latency and underestimate sleep duration during on-call periods. It may be beneficial for on-call workers to actively reflect on feelings of fatigue/alertness for workplace fatigue management, rather than relying solely on estimates of sleep.

Moderate-intensity exercise performed in the evening does not impair sleep in healthy males.

The aim of this study was to examine the effect of single bouts of moderate-intensity aerobic exercise and moderate-intensity resistance exercise performed in the evening on the sleep of healthy young males. The study employed a repeated-measures, counterbalanced, crossover design with three conditions (control, evening aerobic exercise, evening resistance exercise). Twelve male participants (mean ± SD; age: 21.9 ± 2.7 yr) attended the laboratory on three occasions separated by one day between each visit. Between 20:45 h and 21:30 h, participants completed either no exercise, 30 min of aerobic exercise at 75%HRmax, or 30 min of resistance exercise corresponding to 75% of 10-repetition maximum. A 9-h sleep opportunity was provided between 23:00 h and 08:00 h. Core body temperature was measured using ingestible temperature capsules and sleep was measured using polysomnography. Core body temperature was higher during the aerobic exercise and resistance exercise compared to control (p = 0.001). There was no difference in core body temperature at bedtime between the conditions. Sleep onset latency, total sleep time, slow-wave sleep duration, REM sleep duration, wake after sleep onset and sleep efficiency were similar in each condition (p > 0.05). Single bouts of moderate-intensity aerobic exercise or moderate-intensity resistance exercise performed in the evening did not impact subsequent night-time sleep. Core body temperature increased during both forms of exercise, but returned to pre-exercise levels in the 90 min prior to bedtime. Healthy young males can engage in a single bout of moderate-intensity aerobic exercise or moderate-intensity resistance exercise ceasing 90 min before bed without compromising their subsequent sleep.

Waking qEEG to assess psychophysiological stress and alertness during simulated on-call conditions.

INTRODUCTION: On-call schedules are associated with stress and disrupted sleep. In a recent study, under non-sleep deprived conditions, low and high-stress on-call conditions did not significantly impact sleep quality but did impact next day performance. Our aim was to determine whether quantitative electroencephalography (qEEG) would reflect changes in cortical activity in on-call conditions, predicting that the high-stress condition would display faster qEEG frequencies compared with the control and low-stress condition. METHODS: Twenty-four healthy male participants (age: 26.5 ±â€¯4.0 yrs) spent four nights in a time-isolated sleep laboratory. The within-subjects, repeated measures experimental design assessed waking EEG, via the Karolinska Drowsiness Test (KDT) during four time-points across a control day and two experimental (on-call) days. Experimental days comprised a low-stress (LS - reading task) and high-stress (HS - speech task) condition and were counterbalanced. Mixed-models analysis was used to assess condition and time by EEG biomarkers: Alpha Attenuation Coefficient (AAC), Slowing Ratio (SR) and Scaling Exponent (SE). RESULTS: Main effects were found for all three biomarkers by condition, with pairwise analysis reported. There was a significant difference in AAC between the LS condition (M = 1.26 ±â€¯=1.24) and HS condition (M = 1.01 ±â€¯0.76 p = .02) indicating decreased alertness between LS and HS. A significant increase in SR between control (M = 7.1 ±â€¯4.3) and LS (M = 10.1 ±â€¯8.5 p = .0001), and a significant increase between the LS and HS (M = 7.8 ±â€¯6.8 p = .018) showing greatest EEG slowing in the LS condition, reflecting of a passive, sleepier brain state. The SE was significantly higher in the LS (M = 1.09, ±0.17) condition compared with control (M = 1.0, ±0.11 p = .001) indicating decreased alertness in the LS task. DISCUSSION: Using qEEG biomarkers, in contrast with our initial hypothesis, the current study found that compared with control, the LS condition resulted in greater EEG slowing. These findings have implications for on-call workers who engage in periods of passive attention and highlight a protective role task stress may play in maintaining alertness levels during on-call conditions.

[Inter-relation of rheumatology and phlebology. Introduction]. / Interrelations rhumato-phlébologiques. Introduction.

After touching on some general ideas about rheumatics, the author concentrates on this question: Is there a connection between arthritis and chronic venous insufficiency? The author mentions the work done in this field by the French, and particularly by the school of Toulouse, and then he turns to a consideration of arthritis in general, concentrating especially on arthritis of the hips and knees; in conclusion: Arthritis is primarily a mechanical disorder and venous insufficiency plays only a contingent role; Krieg's phlebarthritic complexus is a pure coincidence!