| Duration |
Time above 1,000 lx melEDI Bright-light exposure duration; relevant to daytime alerting and circadian entrainment. |
HH:MM |
00:41 (00:11, 01:34) 01:10 ± 01:28 N=141; d=816 |
01:18 (00:31, 03:24) 02:00 ± 01:54 N=13; d=78 |
01:18 (00:29, 02:12) 01:33 ± 01:28 N=13; d=78 |
01:03 (00:20, 02:32) 01:48 ± 02:14 N=18; d=107 |
00:40 (00:07, 01:25) 01:06 ± 01:22 N=26; d=150 |
00:39 (00:10, 01:46) 01:09 ± 01:18 N=10; d=60 |
00:27 (00:06, 00:53) 00:38 ± 00:47 N=23; d=129 |
00:30 (00:06, 01:04) 00:44 ± 00:51 N=17; d=101 |
00:19 (00:09, 00:43) 00:32 ± 00:33 N=6; d=32 |
00:43 (00:17, 01:14) 00:58 ± 00:57 N=15; d=81 |
Symlog (base 10; threshold 1) |
Time above 1,000 lx melEDI distribution by site. Exact numerical summaries are in the adjacent cells. |
Time above 250 lx melEDI during wake Waking time in recommended daytime light; relevant to alertness, entrainment, and subsequent sleep. |
HH:MM |
02:25 (00:51, 04:37) 03:00 ± 02:29 N=141; d=737 |
04:06 (02:30, 06:15) 04:21 ± 02:24 N=13; d=73 |
03:29 (02:03, 05:16) 03:39 ± 02:25 N=13; d=64 |
03:42 (02:05, 05:58) 04:05 ± 02:51 N=18; d=90 |
02:01 (00:47, 04:20) 02:52 ± 02:39 N=26; d=141 |
02:38 (00:55, 04:19) 02:57 ± 02:19 N=10; d=54 |
02:43 (00:54, 04:43) 03:02 ± 02:19 N=23; d=113 |
01:30 (00:41, 03:26) 02:09 ± 01:57 N=17; d=94 |
01:39 (00:32, 02:40) 01:48 ± 01:21 N=6; d=30 |
01:14 (00:25, 02:37) 01:45 ± 01:46 N=15; d=78 |
Symlog (base 10; threshold 1) |
Time above 250 lx melEDI during wake distribution by site. Exact numerical summaries are in the adjacent cells. |
Time below 10 lx melEDI before sleep Low-light time before bed; limits evening melatonin suppression and circadian delay. |
HH:MM |
01:53 (01:02, 02:35) 01:51 ± 01:02 N=139; d=655 |
02:16 (01:30, 02:39) 02:05 ± 00:53 N=13; d=67 |
01:50 (01:21, 02:52) 01:59 ± 00:57 N=12; d=50 |
01:42 (00:53, 02:17) 01:41 ± 00:58 N=18; d=84 |
01:52 (01:04, 02:25) 01:52 ± 01:06 N=26; d=132 |
01:43 (00:42, 02:32) 01:45 ± 01:10 N=10; d=52 |
01:43 (00:58, 02:50) 01:50 ± 01:05 N=23; d=105 |
01:31 (00:48, 02:15) 01:38 ± 01:00 N=17; d=82 |
02:16 (01:15, 02:39) 01:56 ± 01:00 N=6; d=25 |
02:30 (01:28, 02:52) 02:09 ± 00:57 N=14; d=58 |
Symlog (base 10; threshold 1) |
Time below 10 lx melEDI before sleep distribution by site. Exact numerical summaries are in the adjacent cells. |
Time below 1 lx melEDI during sleep Darkness during sleep; supports nocturnal melatonin and an undisturbed sleep environment. |
HH:MM |
07:08 (05:58, 08:15) 07:04 ± 01:57 N=141; d=778 |
07:08 (06:03, 08:18) 07:12 ± 01:46 N=13; d=76 |
07:14 (05:56, 08:06) 07:01 ± 01:50 N=13; d=68 |
07:08 (05:56, 08:16) 07:05 ± 01:50 N=18; d=95 |
06:54 (05:52, 07:46) 06:47 ± 01:30 N=26; d=150 |
05:52 (04:41, 07:03) 05:58 ± 01:58 N=10; d=60 |
08:06 (07:10, 09:10) 08:02 ± 01:57 N=23; d=118 |
06:45 (05:08, 08:15) 06:40 ± 02:07 N=17; d=99 |
06:56 (06:06, 07:36) 06:39 ± 01:43 N=6; d=31 |
07:31 (06:31, 09:00) 07:35 ± 02:15 N=15; d=81 |
Symlog (base 10; threshold 1) |
Time below 1 lx melEDI during sleep distribution by site. Exact numerical summaries are in the adjacent cells. |
Longest period above 250 lx melEDI Longest sustained bright-light bout; captures continuity of daytime circadian stimulation. |
HH:MM |
00:38 (00:17, 01:12) 00:55 ± 01:00 N=141; d=816 |
00:56 (00:28, 01:27) 01:12 ± 01:02 N=13; d=78 |
00:48 (00:23, 01:20) 01:09 ± 01:15 N=13; d=78 |
01:00 (00:21, 01:40) 01:20 ± 01:31 N=18; d=107 |
00:35 (00:13, 01:06) 00:50 ± 00:54 N=26; d=150 |
00:38 (00:18, 01:32) 01:01 ± 01:02 N=10; d=60 |
00:38 (00:16, 01:04) 00:45 ± 00:36 N=23; d=129 |
00:34 (00:14, 00:55) 00:43 ± 00:41 N=17; d=101 |
00:28 (00:16, 00:43) 00:30 ± 00:20 N=6; d=32 |
00:23 (00:15, 00:49) 00:38 ± 00:45 N=15; d=81 |
Symlog (base 10; threshold 1) |
Longest period above 250 lx melEDI distribution by site. Exact numerical summaries are in the adjacent cells. |
| Dynamics |
Interdaily stability Day-to-day regularity of the light–dark pattern; higher regularity supports circadian stability. |
dimensionless |
0.308 (0.248, 0.38) 0.318 ± 0.095 N=141; d=816 |
0.311 (0.272, 0.367) 0.315 ± 0.078 N=13; d=78 |
0.258 (0.239, 0.389) 0.288 ± 0.094 N=13; d=78 |
0.264 (0.219, 0.319) 0.274 ± 0.074 N=18; d=107 |
0.329 (0.263, 0.424) 0.344 ± 0.107 N=26; d=150 |
0.244 (0.218, 0.277) 0.252 ± 0.058 N=10; d=60 |
0.352 (0.321, 0.455) 0.368 ± 0.092 N=23; d=129 |
0.278 (0.254, 0.394) 0.323 ± 0.104 N=17; d=101 |
0.342 (0.315, 0.473) 0.37 ± 0.118 N=6; d=32 |
0.293 (0.255, 0.354) 0.299 ± 0.062 N=15; d=81 |
Identity |
Interdaily stability distribution by site. Exact numerical summaries are in the adjacent cells. |
Intradaily variability Within-day fragmentation of light exposure; higher values indicate less consolidated light–dark input. |
dimensionless |
1.253 (0.93, 1.502) 1.229 ± 0.389 N=141; d=816 |
0.997 (0.818, 1.388) 1.088 ± 0.343 N=13; d=78 |
1.193 (0.96, 1.389) 1.238 ± 0.345 N=13; d=78 |
1.182 (0.928, 1.49) 1.177 ± 0.407 N=18; d=107 |
1.154 (0.801, 1.442) 1.125 ± 0.354 N=26; d=150 |
1.48 (0.869, 1.642) 1.332 ± 0.477 N=10; d=60 |
1.251 (0.999, 1.497) 1.251 ± 0.413 N=23; d=129 |
1.359 (0.95, 1.546) 1.307 ± 0.415 N=17; d=101 |
1.399 (1.282, 1.483) 1.355 ± 0.256 N=6; d=32 |
1.324 (1.029, 1.595) 1.344 ± 0.413 N=15; d=81 |
Identity |
Intradaily variability distribution by site. Exact numerical summaries are in the adjacent cells. |
| Exposure history |
melEDI dose Intensity–duration-weighted melanopic exposure; summarizes cumulative non-visual retinal light input. |
klx·h |
4.96 (1.936, 12.313) 10.358 ± 16.216 N=141; d=761 |
9.296 (3.892, 21.895) 19.923 ± 27.784 N=13; d=71 |
10.495 (3.855, 17.395) 15.881 ± 20.395 N=13; d=74 |
6.751 (2.469, 14.435) 13.809 ± 23.711 N=18; d=97 |
3.862 (1.411, 10.217) 7.719 ± 9.847 N=26; d=137 |
7.11 (1.897, 15.789) 10.055 ± 11.237 N=10; d=55 |
3.317 (1.703, 6.29) 6.115 ± 8.79 N=23; d=125 |
4.35 (1.791, 10.625) 7.49 ± 8.898 N=17; d=96 |
2.195 (1.339, 4.117) 3.281 ± 2.573 N=6; d=30 |
6.045 (2.49, 14.907) 10.016 ± 10.799 N=15; d=76 |
Symlog (base 10; threshold 1) |
melEDI dose distribution by site. Exact numerical summaries are in the adjacent cells. |
| Level |
Mean melEDI Geometric average of daily melEDI values, including zeros; summarizes overall exposure while reducing peak influence. |
lx |
5.154 (2.831, 9.225) 7.587 ± 9.496 N=141; d=816 |
7.569 (4.55, 11.613) 9.171 ± 7.111 N=13; d=78 |
6.659 (4.18, 11.674) 8.274 ± 6.558 N=13; d=78 |
7.704 (3.081, 13.924) 12.017 ± 18.865 N=18; d=107 |
5.232 (3.224, 8.188) 7.221 ± 6.33 N=26; d=150 |
9.013 (4.011, 15.089) 12.102 ± 12.013 N=10; d=60 |
3.505 (1.469, 6.211) 4.166 ± 3.272 N=23; d=129 |
5.857 (3.726, 7.986) 7.778 ± 6.946 N=17; d=101 |
4.325 (3.585, 6.77) 5.248 ± 2.85 N=6; d=32 |
2.144 (0.744, 4.042) 3.019 ± 2.896 N=15; d=81 |
Symlog (base 10; threshold 1) |
Mean melEDI distribution by site. Exact numerical summaries are in the adjacent cells. |
Brightest 10 h mean Mean of the brightest 10 hours; reflects the strength of the main daytime light episode. |
lx |
110.566 (41.513, 243.212) 214.866 ± 508.56 N=141; d=816 |
252.689 (104.514, 461.953) 399.302 ± 518.102 N=13; d=78 |
175.974 (78.625, 299.106) 262.206 ± 329.201 N=13; d=78 |
156.184 (67.783, 339.731) 422.54 ± 1,209.616 N=18; d=107 |
100.057 (33.255, 209.904) 179.372 ± 241.53 N=26; d=150 |
130.78 (54.044, 259.726) 201.947 ± 194.042 N=10; d=60 |
101.102 (24.355, 218.457) 136.312 ± 134.07 N=23; d=129 |
83.24 (53.17, 151.786) 120.172 ± 101.545 N=17; d=101 |
68.143 (45.331, 132.458) 96.735 ± 72.311 N=6; d=32 |
46.66 (9.242, 103.175) 82.489 ± 115.07 N=15; d=81 |
Symlog (base 10; threshold 1) |
Brightest 10 h mean distribution by site. Exact numerical summaries are in the adjacent cells. |
Darkest 10 h mean Mean of the darkest 10 hours; lower values during the biological night favour melatonin preservation and sleep. |
lx |
0.103 (0.02, 0.253) 0.243 ± 0.513 N=141; d=816 |
0.08 (0.016, 0.191) 0.183 ± 0.299 N=13; d=78 |
0.1 (0.035, 0.23) 0.2 ± 0.332 N=13; d=78 |
0.14 (0.036, 0.282) 0.223 ± 0.299 N=18; d=107 |
0.149 (0.074, 0.309) 0.273 ± 0.465 N=26; d=150 |
0.325 (0.119, 0.71) 0.515 ± 0.653 N=10; d=60 |
0.022 (0, 0.08) 0.054 ± 0.075 N=23; d=129 |
0.152 (0.052, 0.481) 0.475 ± 0.882 N=17; d=101 |
0.133 (0.055, 0.309) 0.411 ± 1.044 N=6; d=32 |
0.01 (0, 0.092) 0.059 ± 0.104 N=15; d=81 |
Symlog (base 10; threshold 1) |
Darkest 10 h mean distribution by site. Exact numerical summaries are in the adjacent cells. |
| Spectrum |
Melanopic daylight efficacy ratio Mean of viable one-minute melEDI/illuminance ratios; indicates melanopic efficacy relative to visual light. |
dimensionless |
0.724 (0.643, 0.795) 0.724 ± 0.116 N=137; d=687 |
0.788 (0.725, 0.872) 0.796 ± 0.162 N=13; d=74 |
0.743 (0.699, 0.796) 0.743 ± 0.077 N=13; d=65 |
0.781 (0.675, 0.853) 0.768 ± 0.118 N=18; d=97 |
0.65 (0.592, 0.728) 0.667 ± 0.098 N=26; d=144 |
0.724 (0.652, 0.773) 0.72 ± 0.093 N=10; d=55 |
0.668 (0.629, 0.721) 0.673 ± 0.07 N=22; d=83 |
0.747 (0.634, 0.834) 0.735 ± 0.122 N=17; d=91 |
0.719 (0.661, 0.761) 0.706 ± 0.067 N=6; d=30 |
0.755 (0.729, 0.82) 0.758 ± 0.097 N=12; d=48 |
Identity |
Melanopic daylight efficacy ratio distribution by site. Exact numerical summaries are in the adjacent cells. |
| Timing |
Midpoint of the brightest 10 hours Centre time of the brightest 10 hours; indexes the main daily circadian light cue. |
HH:MM clock time |
13:44 (12:48, 15:00) 13:56 ± 01:51 N=141; d=816 |
13:16 (12:28, 14:10) 13:20 ± 01:33 N=13; d=78 |
14:12 (13:23, 15:18) 14:22 ± 01:51 N=13; d=78 |
13:52 (12:54, 15:04) 14:00 ± 01:42 N=18; d=107 |
13:38 (12:47, 14:44) 13:52 ± 01:42 N=26; d=150 |
14:54 (12:50, 16:03) 14:31 ± 02:14 N=10; d=60 |
13:44 (13:06, 15:20) 14:10 ± 01:51 N=23; d=129 |
14:10 (13:32, 15:21) 14:25 ± 01:37 N=17; d=101 |
12:34 (11:49, 14:02) 12:55 ± 01:44 N=6; d=32 |
12:49 (12:06, 13:39) 13:03 ± 01:58 N=15; d=81 |
Circular clock |
Midpoint of the brightest 10 hours distribution by site. Exact numerical summaries are in the adjacent cells. |
Midpoint of the darkest 10 hours Centre time of the darkest 10 hours; indexes the main daily darkness cue. |
HH:MM clock time |
02:54 (02:01, 03:50) 02:58 ± 01:41 N=141; d=816 |
02:02 (01:24, 02:48) 02:03 ± 01:07 N=13; d=78 |
02:55 (02:01, 03:28) 02:50 ± 02:05 N=13; d=78 |
02:32 (01:45, 03:22) 02:37 ± 01:19 N=18; d=107 |
03:08 (02:11, 04:10) 03:16 ± 01:34 N=26; d=150 |
02:37 (01:54, 04:17) 03:10 ± 02:00 N=10; d=60 |
03:39 (02:43, 04:34) 03:34 ± 01:49 N=23; d=129 |
03:31 (02:33, 04:14) 03:26 ± 01:25 N=17; d=101 |
01:45 (01:05, 03:01) 02:10 ± 01:27 N=6; d=32 |
02:33 (02:04, 03:17) 02:36 ± 01:36 N=15; d=81 |
Circular clock |
Midpoint of the darkest 10 hours distribution by site. Exact numerical summaries are in the adjacent cells. |
First light timing above 250 lx melEDI First waking bright-light exposure; morning timing can advance circadian phase and promote alertness. |
HH:MM clock time |
09:08 (08:02, 10:40) 09:26 ± 02:22 N=140; d=727 |
07:57 (06:56, 08:33) 08:03 ± 01:32 N=13; d=74 |
09:04 (08:18, 09:52) 09:17 ± 01:56 N=13; d=68 |
08:36 (07:10, 10:13) 08:45 ± 02:21 N=18; d=93 |
09:43 (08:13, 10:53) 09:45 ± 02:21 N=25; d=133 |
09:36 (07:58, 10:53) 09:39 ± 03:12 N=10; d=56 |
09:32 (08:40, 11:21) 10:05 ± 02:18 N=23; d=118 |
10:01 (09:06, 11:52) 10:26 ± 02:28 N=17; d=95 |
08:11 (07:26, 09:57) 08:36 ± 01:30 N=6; d=29 |
08:43 (08:01, 10:10) 09:19 ± 01:52 N=15; d=61 |
Circular clock |
First light timing above 250 lx melEDI distribution by site. Exact numerical summaries are in the adjacent cells. |
Last light timing above 250 lx melEDI Last bright-light exposure; later timing may delay circadian phase and sleep onset. |
HH:MM clock time |
18:08 (16:27, 19:42) 18:03 ± 02:36 N=141; d=687 |
18:41 (17:38, 19:38) 18:39 ± 01:38 N=13; d=73 |
18:30 (17:37, 19:59) 18:37 ± 02:08 N=13; d=62 |
19:34 (18:04, 20:42) 19:16 ± 02:28 N=18; d=89 |
17:37 (15:35, 19:09) 17:18 ± 02:44 N=26; d=121 |
19:50 (18:37, 20:50) 19:33 ± 02:11 N=10; d=53 |
17:48 (16:46, 19:19) 18:01 ± 02:21 N=23; d=106 |
18:45 (17:02, 19:38) 18:23 ± 02:15 N=17; d=89 |
15:45 (13:20, 16:38) 15:22 ± 02:38 N=6; d=28 |
15:54 (14:34, 17:25) 15:46 ± 02:13 N=15; d=66 |
Circular clock |
Last light timing above 250 lx melEDI distribution by site. Exact numerical summaries are in the adjacent cells. |
Mean timing of exposure above 250 lx melEDI Average bright-light timing; summarizes the phase of daily circadian stimulation. |
HH:MM clock time |
13:29 (12:29, 14:39) 13:31 ± 01:52 N=141; d=742 |
13:20 (12:29, 14:24) 13:21 ± 01:25 N=13; d=72 |
13:52 (13:13, 15:06) 14:02 ± 01:41 N=13; d=71 |
13:44 (12:28, 14:55) 13:51 ± 01:56 N=18; d=93 |
13:17 (12:17, 14:31) 13:24 ± 01:45 N=26; d=138 |
14:04 (12:58, 15:25) 14:09 ± 02:22 N=10; d=55 |
13:43 (12:55, 14:29) 13:47 ± 01:33 N=23; d=117 |
13:58 (12:54, 14:58) 14:04 ± 01:39 N=17; d=94 |
11:30 (10:28, 12:38) 11:26 ± 01:36 N=6; d=31 |
12:17 (11:04, 13:04) 12:11 ± 01:36 N=15; d=71 |
Circular clock |
Mean timing of exposure above 250 lx melEDI distribution by site. Exact numerical summaries are in the adjacent cells. |