Long-term sleep deprivation as a game. The wear and tear of wakefulness

Why we sleep: the temporal organization of recovery

Why we sleep seems like a simple question, yet it has baffled scientists for generations. Based on recent data, Emmanuel Mignot argues that the function of sleep is essentially a resilient form of cellular recovery, organized anatomically and temporally by natural evolution, that has taken on additional functions over time.

Effects of Total Sleep Deprivation on Cardiovascular Parameters: An Absence of Biologically Significant Findings?

Abstract The present study analyzes the variations of heart rate (HR) and systolic and diastolic blood pressure (SBP and DBP) during 60 h of total sleep deprivation (TSD). All variables were evaluated every 2 h in a resting condition, during the performance of a vigilance task. Thirty healthy volunteers (15 men and 15 women) from 18 to 24 years old participated in the experiment. The analyses of variance (ANOVAS) with repeated measures showed some modifications of HR and SBP mean values mainly marked by circadian oscillations. The circadian oscillations had a smaller amplitude for SBP than for HR. HR showed a slight decrease on the second night of TSD and a slight increase on the third day of TSD. SBP decreased during the first 24 h of TSD and after that maintained its values without significant changes. DBP did not show any significant variations during TSD. In addition, there were no differences in function of gender for the TSD effect on the studied variables. All these statistically significant findings, however, seem to have no biological or clinical relevance. These aspects as well as the possible relationships between our results and activation or stress levels during TSD are discussed.

A 20-h recovery sleep after prolonged sleep restriction: some effects of competing in a world record-setting cinemarathon

The recovery sleep of a 21-year-old normal woman was assessed after she had endured 11(1/2) days of sleep restriction in a world record-setting film-viewing marathon. An exceptional sleep debt was observed as indicated by an instanteous sleep onset, a high sleep efficiency, and a total sleep duration of over 20 hours. Other striking features of this recovery sleep were very short latencies to stages 3 and 4 sleep, return of Stage 4 sleep after 14.5 h, REM and SWS sleep rebound, and a linear increase in REM sleep efficiency across 14 consecutive REM-NREM episodes. Seven of nine home dreams reported after this recording contained competition themes, but none relating to the marathon films. Comparisons of the present results with those from subjects in previous record-setting events suggest possible explanations for the extremely long recovery sleep. Results also suggest that analyses of multiple consecutive sleep cycles may provide novel ways of assessing hypotheses about regulation of the REM-NREM cycle.

A proposal for computer-based sleep/wake analysis

The task group on Signal Analysis within the EC Concerted Action 'Methodology for the analysis of the sleep-wakefulness continuum' has proposed general guidelines for a computer-based sleep analyser that would not suffer from the most conspicuous limitations of manual standard scoring. The proposal specifies a standard format for digitized polygraphic recordings, a basic structure of the analyser, and a graphical output format for the analysis results. These analysis results include all sleep/wake related signal characteristics, an on/off REM sleep/wake process, and a continuous-scale NREM sleep/wake process, all with a time resolution of 1s. Several locally available sleep analysers were made to comply with these specifications and then applied to standardized digital polygraphic sleep recordings that were circulated among the laboratories. Analysis results were distributed, enabling evaluation of the local algorithms.