Table 1.
Characteristics of cortisol circadian rhythm: comparison of mean (±95% CIs) cortisol concentrations, AUC, and time variables in our healthy reference group (19) with similar variables in previously published data
| Author | Sample mean age (range) | AUC (h*μg/dl) | Peak (μg/dl) | Trough (μg/dl) | 24-hr mean cortisol (μg/dl) | Time of peak or acrophase (h:min) | Time of nadir (h:min) | Quiescent phase start (h:min) | Quiescent phase end (h:min) |
|---|---|---|---|---|---|---|---|---|---|
| Darzy and Shalet (19) (24 males; 9 Females)a | 27 (17–57) | 160.2 (148.6–171.6) | 16.0 (14.6–17.4) | 2.5 (1.8–3.2) | 6.7 (5.9–7.5) | 08:32 (07:59–09:05) | 00:18 (23:39–0:58) | 19:43 (18:36–20:49)b | 05:31 (04:45–06:18)c |
| Other authors (20,21,22,23,24,25,26,27,28,29) (127 males; 38 females)d | 32 (19–59) | 169.0 (138.5−207.0) | 15.0 (11.6−19.0) | 2.04 (1.0–3.2) | 7.7 (5.7–15.8) | 07:49 (06:28−09:01) | 00:30 (22:00–02:00) | 19:40 (16:30−22:00)e | 04:11 (03:00−05:30)f |
Sample subgroups used in analysis were: 20- to 29-yr subgroup (21); 19- to 25-yr subgroup (22); S1 session (24); control group (25); and Chinese, 30-yr subgroup (26). The AUC (23) represents the average of harmonic regressions. Not used in analysis of: Trough (22), 24-h mean cortisol (22,28), Time of Nadir (26,27,29), Quiescent phase start (26,27,29), and Quiescent phase end (27,29).
Variable mean (95% CIs).
Period starts when the cortisol level is approximately 5.2 μg/dl or less for at least 1 h.
Period starts when the cortisol levels are approximately 5.2 μg/dl or more for at least 1 h.
Values have been estimated from published data: mean (range).
Period starts when the cortisol level is approximately 5.0 μg/dl or less for at least 1 h.
Period starts when the cortisol levels are approximately 5.0 μg/dl or more for at least 1 h.