The rectal temperature has been measured on normally active or on resting subjects by means of a continuous recording device under the following conditions: a) In ~n underground bunker with constant illumination and with room-temperature ~t choice where all known Zeitgebers had been excluded; b) In the same bunker with a 12:12-hour light-dark-cycle as Zeitgeber; c) In a climatic chamber with constant temperature, the subjects knowing time of day, and illuminated at choice. The snbjeets measured under conditions a) showed typical free-running circadian periods (average duration: 25,3 hours) in their activity-cycle as well as in their body temperature. The subjects measured in conditions b) and e) were all synchronized to 24 hours. For comparison, other normal curves of body temperature were taken from the literature.
In all subjects synchronized with a Zeitgeber, the maxima of body temperature fell on the second half of the activity-time, the minima on the second half of the rest-time; the ratio between the time spans of the ascending and the descending part of the average temperature curve of all subjects was 1.6. In nine out of ten subjects measured without Zeitgeber, the maxima fell on the first half of the activitytime, and the minima (in all cases) on the first half of the rest-time or at the end of the activity-time; the ratio between the time spans of the ascending and descending part of the average temperature curve for all subjects was 1.1.
The results suggest to consider the activity-cycle and the temperature cycle as two coupled oscillators, between which the phase-angle difference changes considerably when after the exclusion of external Zeitgebers, they start to oscillate with a spontaneous circadian frequency.
Zusammen/assung. Mit fortlaufender
Registrierung wurden die Reetaltemperaturen normal tiitigcr oder ruhender Versuchspersonen unter folgenden Bedingungen gemessen: a) In einem unterirdischen Bunker bei konstanter Beleuchtung uad Temperatur nach Wahl muter Ausschlu$ aller bekannten Zeitgeber; b) Im selben Bunker bei einem 12:12 stiindigem Lieht-Dunkel-Weehsel als Zeitgeber; e) In einer I~imakammer bei konstanter Temperatur unter Kenntnis der Uhrzeit mud bei Beleuchtung naeh 'Wahl. Die unter Bedingung a) untersuchten Personen zeigten in ihrem Schlaf-Wach-Rhythmus wie in der KSrpertemperatur typisehe cireadiane Perioden (mittlere Periodendauer: 25,3 Std). Die unter b) und c) untersuehten Per-* Die Experimente wurden mit Nfitteln des Bundesministeriums fiir wissenschaftliche Forschung (FSrderungs-Vorhaben WRK 56 und WRK 86) und Mitteln der NASA (Grant ]~SG-259-62) gefSrdert.