Adaptation to abrupt time shifts of the oscillator(s) controlling human circadian rhythms.
- 1 December 1978
- journal article
- Published by Wiley in The Journal of Physiology
- Vol. 285 (1), 455-470
- https://doi.org/10.1113/jphysiol.1978.sp012582
Abstract
1. Thirty-six subjects in an isolation unit were subjected to time shifts of 12 hr, or of 8 hr in either direction. 2. The rhythms of body temperature and excretion of eight urinary constituents were studied before and after the shift, both on a usual nychthemeral routine and during 24 hr when they remained under constant conditions, awake, engaged in light, mainly sedentary activity, and consuming identical food and fluid every hour. 3. The rhythms on nychthemeral routine were defined by fitting cosine curves. On constant routine the rhythm after the shift was cross-correlated with the original rhythm, either with variable delay (or advance) or with an additive mixture between this variably shifted rhythm and the unshifted or a fully shifted rhythm. The process yielding the highest correlation coefficient was accepted as the best descriptor of the nature of adaptation. 4. A combination of two rhythms was observed more often for urinary sodium, chloride and phosphate than for other variables. 5. Adaptation appeared to have proceeded further after westward than eastward shifts, and this difference was particularly noticeable for urinary potassium, sodium and chloride. 6. Partial adaptation usually involved a phase delay, even after an eastward shift when a cumulative delay of 16 hr would be needed to achieve full adaptation and re-entrainment. 7. Observations under nychthemeral conditions often gave a false idea of the degree of adaptation. In particular, after an eastward shift the phase of the rhythms appeared to shift in the appropriate direction when studied under nychthemeral conditions whereas the endogenous oscillator either showed no consistent behaviour or, in the control of urate excretion, a shift in the wrong direction. 8. The implications for people undergoing time shifts, in the course of shift work or transmeridional flights, are indicated.Keywords
This publication has 17 references indexed in Scilit:
- EFFECT OF SLEEP UPON HUMAN CIRCADIAN-RHYTHMS1978
- Cortisol-mediated synchrinization of circadian rhythm in urinary potassium excretionAmerican Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 1977
- The physiological rhythms of subjects living on a day of abnormal length.The Journal of Physiology, 1977
- Internal organization of the circadian timing system in multicellular animals.1976
- A SIMPLE METHOD FOR IMPROVING THE SPECIFICITY OF THE FLUORIMETRIC DETERMINATION OF ADRENAL CORTICOSTEROIDS IN HUMAN PLASMAJournal of Endocrinology, 1965
- A simple fluorimetric method for the estimation of free 11-hydroxycorticoids in human plasmaJournal of Clinical Pathology, 1962
- DIURNAL RHYTHM IN WATER, CHLORIDE, SODIUM AND POTASSIUM EXCRETION DURING A RAPID DISPLACEMENT FROM EAST TO WEST AND VICE VERSA1962
- ON THE SIGNIFICANCE OF TRANSIENTS IN DAILY RHYTHMSProceedings of the National Academy of Sciences, 1958
- Rhythmic Diurnal Variations in the Behaviour of the Human Renal TubuleActa Medica Scandinavica, 1955
- A RECIPROCAL RELATIONSHIP BETWEEN K+ AND H+ EXCRETION IN THE DIURNAL EXCRETORY RHYTHM IN MAN1954