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Biomedical subjects

J A Horne

Publications and source records attributed to J A Horne.

8 recordsLinked to original sources
PubMed1978

A review of the biological effects of total sleep deprivation in man.

This biologically oriented review attempts to complement earlier and more psychological performance based reviews of total sleep deprivation. Also, the effects of total sleep deprivation are interpreted, here, from a function of human sleep perspective, rather than from the more usual stress viewpoint. It would appear that total sleep deprivation does not produce any major changes in biochemical and physiological measures of somatic functioning. Such a conclusion would not seem to support an hypothesis that human sleep is for body restitution. Although there are equivocal results amongst several of the more psychophysiological measures, EEG does show a pronounced change. This latter finding, together with many reports of psychological performance detriment, would appear to sustain a CNS or cerebral restitutional role for human sleep. However, before definitive conclusions can be drawn from the biochemical and physiological findings of total sleep deprivation, the following qualifications of experimental methodology are made: (1) Apart from sleep loss, many studies have provided unnatural regimes which may have ameliorated possible effects of total sleep deprivation. (2) Most studies are of relatively short duration and may not have been sufficiently long for effects to develop. (3) Measures are often limited in range and depth of analysis. (4) Subjects are mostly fit, young adult, intelligent males and there is little constitutional variability. (5) Reported changes of statistical significance may be of no physiological significance and changes of possible physiological significance may be obscured by statistical procedures. (6) Intervening behavioural variables, such as novelty and anticipation of the sleep deprivation situation, may confound real effects.

17-Hydroxycorticosteroids↗
PubMed1977

Individual differences in human circadian rhythms.

Research into individual differences in circadian rhythms is reviewed, particularly morningness-eveningness. It was hypothesised that extraverts would be inclined towards eveningness and introverts towards morningness. Forty-eight subjects took regularly their oral temperature. Peak times were identified from smoothed temperature curves. Results showed that extraverts had a peak time insignificantly later than introverts. Re-grouping of the data into the morningness-eveningness dimension, based upon the results of a self assessment questionnaire, showed that evening types had significantly later peak times than morning types. Morningness-eveningness was not significantly ocrrelated with extraversion-introversion, although there was a trend. No significant differences were found for sleep lengths with either groupings, or for sleep-wake habits within extraversion-introversion. Morning types retired and arose significantly earlier than evening types. Although sleep-wake habits and extraversion-introversion help to determine peak times there are other contributory factors to peak time which appear to be partly covered by the questionnaire.

Adolescent↗
PubMed1976

Ultradian and other rhythms in human respiration rate.

Twelve male subjects had their respiration rate (RR) measured at 3 min intervals for 6 h. Although there were substantial individual differences, most subjects demonstrated a 90 +/- 15 min rhythm of RR, with several subjects also showing 60 +/- 10 min and 30 +/- 3 min rhythms.

Adolescent↗
PubMed1976

Time of day effects with standardized exercise upon subsequent sleep.

The effect standardized exercise had upon sleep was studied with eight subjects. A pilot study assessed individual work capacity by the sub-maximal estimation of VO2 max. In the main study each subject performed the exercise, once a.m. and once p. m., on different days. Sleep was scored into stages and an additional sub-division of stage 2 containing 10-20% by time of delta. Comparison with baseline showed no significant whole night changes with any criteria following either a.m. or p. m. exercise. After p.m. exercise there was a significant increase in stage 3 for the first half of the night. It was concluded that ensuing wakefulness following early daytime exercise is sufficient for recovery, but late daytime exercise may result in an intrusion of recovery into initial sleep. Sleep is not seen to be necessary for recovery from muscular fatigue.

Adolescent↗
PubMed1976

Recovery sleep following different visual conditions during total sleep deprivation in man.

The findings of visual impairment during total sleep deprivation were used as a basis for a possible link between vision and sleep. It was proposed that the level of visual load imposed during sleep deprivation was an important variable, and would have a substantial effect upon recovery sleep. Six young male subjects underwent two conditions of 64 h of sleep deprivation on separate occasions. One condition incorporated a high visual load, and the other a low load. Exercise and sound were balanced. All night sleep EEGs were taken for two baseline nights, and also for two recovery nights following each condition. There was a significant increase of stage 4 on all recovery nights and a REM rebound on the second recovery night. SWS, particularly stage 4, TST and REM density, were significantly greater following the high load. Implications of these findings for sleep theories and for sleep deprivation research are discussed.

Adult↗