Sengele Population Sleep Chronotype Measurements

Sleep midpoint data (minutes from midnight) for 33 Sengele subjects across multiple nights, with age and sex demographics.
# Population
subject
sex
age
CPM.minutes.from.midnight
1 Sengele 1 female 32 196
2 Sengele 1 female 32 269
3 Sengele 1 female 32 223
4 Sengele 1 female 32 191
5 Sengele 1 female 32 146
6 Sengele 1 female 32 161
7 Sengele 1 female 32 245
8 Sengele 1 female 32 189
9 Sengele 1 female 32 181
10 Sengele 1 female 32 172
11 Sengele 1 female 32 164
12 Sengele 1 female 32 211
13 Sengele 1 female 32 184
14 Sengele 1 female 32 196
15 Sengele 1 female 32 156
16 Sengele 1 female 32 205
17 Sengele 1 female 32 165
18 Sengele 1 female 32 187
19 Sengele 1 female 32 177
20 Sengele 1 female 32 236
21 Sengele 2 female 30 250
22 Sengele 2 female 30 181
23 Sengele 2 female 30 177
24 Sengele 2 female 30 219
25 Sengele 2 female 30 161
26 Sengele 2 female 30 248
27 Sengele 2 female 30 231
28 Sengele 2 female 30 242
29 Sengele 2 female 30 274
30 Sengele 2 female 30 184
31 Sengele 2 female 30 300
32 Sengele 2 female 30 211
33 Sengele 2 female 30 256
34 Sengele 2 female 30 279
35 Sengele 2 female 30 183
36 Sengele 2 female 30 251
37 Sengele 2 female 30 295
38 Sengele 2 female 30 201
39 Sengele 2 female 30 227
40 Sengele 3 female 34 257
41 Sengele 3 female 34 194
42 Sengele 3 female 34 156
43 Sengele 3 female 34 189
44 Sengele 3 female 34 234
45 Sengele 3 female 34 262
46 Sengele 3 female 34 269
47 Sengele 3 female 34 194
48 Sengele 3 female 34 247
49 Sengele 3 female 34 195
50 Sengele 3 female 34 311
51 Sengele 3 female 34 241
52 Sengele 3 female 34 202
53 Sengele 3 female 34 286
54 Sengele 3 female 34 206
55 Sengele 3 female 34 326
56 Sengele 3 female 34 231
57 Sengele 3 female 34 215
58 Sengele 3 female 34 220
59 Sengele 3 female 34 268
60 Sengele 4 male 46 183
61 Sengele 4 male 46 215
62 Sengele 4 male 46 234
63 Sengele 4 male 46 166
64 Sengele 4 male 46 190
65 Sengele 4 male 46 184
66 Sengele 4 male 46 206
67 Sengele 4 male 46 221
68 Sengele 4 male 46 240
69 Sengele 5 female 38 226
70 Sengele 5 female 38 266
71 Sengele 5 female 38 272
72 Sengele 6 female 26 235
73 Sengele 6 female 26 214
74 Sengele 6 female 26 228
75 Sengele 6 female 26 185
76 Sengele 6 female 26 219
77 Sengele 6 female 26 274
78 Sengele 6 female 26 185
79 Sengele 6 female 26 222
80 Sengele 6 female 26 232
81 Sengele 7 female 55 271
82 Sengele 7 female 55 239
83 Sengele 7 female 55 239
84 Sengele 7 female 55 223
85 Sengele 7 female 55 212
86 Sengele 7 female 55 193
87 Sengele 7 female 55 262
88 Sengele 7 female 55 247
89 Sengele 7 female 55 220
90 Sengele 8 female 45 251
91 Sengele 8 female 45 196
92 Sengele 8 female 45 229
93 Sengele 8 female 45 202
94 Sengele 8 female 45 212
95 Sengele 8 female 45 220
96 Sengele 8 female 45 241
97 Sengele 8 female 45 222
98 Sengele 8 female 45 283
99 Sengele 9 female 60 198
100 Sengele 9 female 60 220

Sengele Population Sleep Chronotype Measurements — Analysis

Sengele sleep midpoint averages 3:47 AM — older adults (56-65) sleep nearly an hour earlier than youngest adults (18-25)

Night-to-night variability is large: individual subjects shift by up to 4.5 hours between nights

About this dataset

This dataset from Zenodo (#4948904) captures circadian phase data from 36 primate subjects (390 observations) studied to understand how individual chronotype variation drives sentinel-like vigilance behaviour. The key measure — CPM (circadian phase marker, in minutes from midnight) — has a median of 228 minutes (~3:48 AM), but spans a striking range from 34 to 407 minutes, suggesting substantial individual variation in internal clock timing. The most surprising pattern: 3 statistical outliers in circadian phase deviate sharply from the group norm (μ=227, σ=50), hinting that extreme early- or late-phase individuals may play disproportionate roles in group vigilance by being awake when others sleep. Subjects ranged in age from 18 to 65 (median 30), with females making up 60% of the sample — a skew that may reflect sex-based differences in chronotype or sentinel duty allocation. Understanding how biological clocks distribute wakefulness across a social group has implications for both animal behaviour research and human chronobiology.

Sleep Timing in the Sengele Population

  • Mean sleep midpoint across 33 subjects is 227 minutes after midnight (3:47 AM), ranging from 2:50 AM to 4:44 AM
  • Age and chronotype are negatively correlated (r = -0.44): subjects aged 56-65 average 3:16 AM vs. 4:06 AM for 18-25-year-olds
  • No meaningful sex difference in sleep timing (females 3:46 AM vs. males 3:49 AM, n=21F/12M)
  • Within-subject night-to-night variability is substantial — SD ranges from 22 to 80 minutes across individuals
  • The most variable sleeper (Subject 26, female, age 30) shifted by up to 267 minutes between nights

Visualizations

Night-to-Night Sleep Variability by Subject
Distribution of All Sleep Midpoint Observations
Sleep Midpoint by Age Group
Mean Sleep Midpoint by Subject

Expand Analysis

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