Circadian influences on clinical values in man.

1. The circadian patterns of clinically relevant parameters were studied in 109 young, healthy soldiers. 2. Erythrocytes, hematocrit, creatinine and cortisol exhibited very stable rhythmic patterns which were found by continuous examinations of the same persons as well as in examinations of different persons at different times. 3. The rhythmic patterns of leukocytes, blood glucose and body temperature were strongly influenced by stress caused by the first confrontation with an unknown hospital-like situation or by pain caused by blood sampling.