Table 2.
(a) Summary of habitual sleep times and (b) melatonin secretion onset and offset times, DPG rise/decline and phase angles.
| Condition | Reference room | Test room | p value |
|---|---|---|---|
|
Clock time [hh:mm] Mean ± SD |
|||
| (a) | |||
| Midsleep | 04:02 ± 00:39 | 04:14 ± 00:40 | 0.23 |
| Waketime | 07:58 ± 00:36 | 08:05 ± 00:48 | 0.86 |
| Sleep onset | 00:05 ± 00:56 | 00:23 ± 00:46 | 0.66 |
| Sleep duration | 07:53 ± 00:52 | 07:41 ± 00:51 | 0.44 |
|
Time since habitual midsleep [hh:mm, mean ± SD] (Clock time; [hh:mm, mean ± SD]) # |
|||
| (b) | |||
| Time of half-maximum dose of accumulated Ev |
09:32 ± 01:22 (13:35 ± 01:01) |
08:42 ± 01:16 (12:57 ± 01:03) |
0.027 |
| Melatonin secretion onset |
17:05 ± 1:29 (21:07 ± 01:31) |
16:40 ± 01:18 (20:54 ± 01:18) |
0.048 |
| Melatonin secretion offset |
05:02 ± 00:56 (09:04 ± 01:01) |
04:56 ± 00:54 (09:11 ± 01:00) |
0.62 |
| DPG rise |
18:56 ± 01:08 (22:58 ± 1:30) |
18:36 ± 00:56 (22:48 ± 01:07) |
0.10 |
| DPG decline |
03:53 ± 00:44 (07:55 ± 00:50) |
03:34 ± 00:33 (07:47 ± 00:46) |
0.011 |
| Time [hh:mm] Mean ± SD | |||
| Phase angle melatonin onset = (sleep onset minus melatonin secretion onset) | 02:58 ± 01:41 | 3:29 ± 01:22 | 0.009 |
| Phase angle DPG rise = (sleep onset minus DPG rise) | 01:07 ± 01:00 | 01:34 ± 01:00 | 0.042 |
| Phase angle DPG decline = (waketime minus DPG decline) | 00:02 ± 00:28 | 00:15 ± 00:26 | 0.049 |
(a) Habitual midsleep time, waketime, sleep onset time and sleep duration (hh:mm), mean per condition ± SD (derived from activity watches) are shown for both conditions (derived from the 7 nights prior the laboratory week and were used for calculation of melatonin and DPG onset, offset times and phase angles during both room conditions in (b)); (b) time of half-maximum dose of accumulated Ev, melatonin onset and offset times, DPG rise and decline times since midsleep (these times are also indicated in clock times, in brackets). Phase angle durations are shown for time ranges between: melatonin onset time and sleep onset time; DPG rise time and sleep onset time; DPG decline time and waketime. Significant p values are shown in bold; # clock times derived from habitual midsleep time for each condition separately; average midsleep time differed by 12 min between the two conditions (p = 0.23).