Task variables determine which biological clock controls circadian rhythms in human performance

Abstract

There are circadian (approximately 24 h) rhythms for a wide range of human physiological and psychological functions including mood and performance efficiency. These rhythms are self-sustaining in conditions of temporal isolation, indicating that internal oscillators (or biological clocks) control them. Recent research has proposed an endogenous two-oscillator model of the human circadian system, with one oscillator indicated by the core body temperature rhythm and a second oscillator responsible for the daily cycle of sleep and wakefulness. The present study was designed to produce a desynchronization in period between the two oscillators, to assess directly the behaviour of the rhythms of different performance tasks. The results, reported here, indicate that a simple manual dexterity task is almost entirely under the control of the temperature rhythm oscillator, whereas a more complex cognitive task demonstrates a periodicity which appears to be influenced by those oscillators controlling temperature and the sleep/wake cycle.

An assessment of the relevance of laboratory and motorcycling tests for investigating time of day and sleep deprivation influences on motorcycling performance

“…This confirms the hypothesis that motor coordination rhythm follows the body temperature rhythm (Monk et al, 1983;Monk et al, 1984) and the rhythm of nervous conduction speed (Ferrario et al, 1980).…”

Memory and menstrual cycle

“…Much research has now established that there are replicable variations in performance over the 24-hour period (e-g. Blake 1971, Colquhoun 1971, Baddeley et al 1970. Reaction time, vigilance and manual dexterity performance peak late in the day, accompanying the rise in body temperature, and reach their worst late at night when body temperature is lowest (Colquhoun 1971, Monk et al 1983. Logical reasoning has also been found to vary over the day (Blake 1971, Folkard 1975.…”

Diurnal Variation in a Visual-Motor Coordination Test in Healthy Humans

“…1). In this respect, Folkard et al (1983) and Monk et al (1983) suggested that the performance in tasks not dependent on memory is related to the oscillator that controls the temperature rhythm. On the other hand, the correlation test failed to detect significance for women.…”

“…Whereas some variations in performance may parallel the arousal, this may not be so for others (Owens et al, 1998), suggesting that different tasks may be under the control of different circadian oscillators (Monk et al, 1983;Folkard et al, 1983). Thus, alertness measures may satisfactorily predict cognitive performance but not simple perceptual-motor speed (Gillooly et al, 1990).…”