| 释义 |
ultradian, a.|ʌlˈtreɪdɪən|
[f. ultra- + L. di-ēs day + -an.]
Designating cycles of physiological activity which recur with a period shorter than one day but longer than one hour. Cf. circadian a.
1961F. Halberg in 39th Rep. Ross Conf. Pediatric Res. 15 Observations have been made on frequencies higher than circadian, yet lower than the respiratory or cardiac cycles (ultradian), and frequencies lower than circadian, but higher than the menstrual cycle (infradian). 1978Nature 3 Aug. 490/1 In humans, REM sleep..occurs every 90–110 min and is presumed to be under the control of an underlying ultradian oscillatory mechanism. |