The effects of total sleep deprivation, selective sleep interruption and sleep recovery on pain tolerance thresholds in healthy subjects

The aim of this study was to compare the effects of total sleep deprivation (TSD), rapid eye movement (REM) sleep and slow wave sleep (SWS) interrupti on and sleep recovery on mechanical and thermal pain sensitivity in healthy adults. Nine healthy male volunteers (age 26-43 years) were randomly assig ned in this double blind and crossover study to undergo either REM sleep or SWS interruption. Periods of 6 consecutive laboratory nights separated by at least 2 weeks were designed as follows: N1 Adaptation night; N2 Baseline night; N3 Total sleep deprivation (40 h); N4 and N5 SWS or REM sleep inter ruption; N6 Recovery. Sleep was recorded and scored using standard methods. Tolerance thresholds to mechanical and thermal pain were assessed using an electronic pressure dolorimeter and a thermode operating on a Peltier prin ciple. Relative to baseline levels, TSD decreased significantly mechanical pain thresholds (-8%). Both REM sleep and SWS interruption tended to decrea se mechanical pain thresholds. Recovery sleep, after SWS interruption produ ced a significant increase in mechanical pain thresholds (+ 15%). Recovery sleep after REM sleep interruption did not significantly increase mechanica l pain thresholds. No significant differences in thermal pain thresholds we re detected between and within periods. In conclusion this experimental stu dy in healthy adult volunteers has demonstrated an hyperalgesic effect rela ted to 40 h TSD and an analgesic effect related to SWS recovery. The analge sic effect of SWS recovery is apparently greater than the analgesia induced by level I (World Health Organization) analgesic compounds in mechanical p ain experiments in healthy volunteers.