Cognitive performance during successive sustained physical work episodes

Abstract

The effects of physical work (30% of {Mathematical expression} max), sleep loss (3-h nap during a 48-h operation), continuous work (CW), and time of day on cognitive performance were assessed (by ANOVA) in this repeated-measures study comparing two groups (exercise/nonexercise) of healthy young men (N=22). Treadmill walking did not accentuate or attenuate sleep loss effects on performance; however, sleep loss alone did degrade visual vigilance and memory for words. Time-of-day fluctuations were found in choice reaction time, logical reasoning, and word memory. Visual vigilance for nonexercising subjects degraded sooner on the 2nd CW day than it did for exercising subjects. A 3-h nap at 0400 h after 1 17-h CW day was not immediately recuperative. These findings indicate that exercise at 30% of {Mathematical expression} max does not compound sleep-loss effects in cognitive performance. Indeed, physical activity during video terminal monitoring may delay any sleep-loss decrement. Variability of many cognitive abilities throughout the day appeared to show a greater effect than the sleep-loss and exercise effects over 2 days. © 1985 Psychonomic Society, Inc.