Open Access

The impact of returning to a daytime schedule on sleep, performance and mood after simulated fixed and rotating split shift schedules

S Centofanti
S Centofanti
, 
M Short
M Short
, 
CJ Hilditch
CJ Hilditch
, 
J Dorrian
J Dorrian
, 
M Kohler
M Kohler
 and 
S Banks
S Banks
   | Sep 30, 2022
Eat, Sleep, Work's Cover Image
About this article
Previous Article
Next Article
Cite
Article Category: Original Paper
Published Online: Sep 30, 2022
Page range: 39 - 56
DOI: https://doi.org/10.21913/JDRSSesw.v1i1.1224
Keywords
© 2020 Centofanti S et al., published by Sciendo
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Figure 1.

Protocol schematics with 24h time across the x-axes. Black bars represent sleep opportunities. Grey bars represent wake time, and boxed grey bars represent on-shift periods. Unshaded crosses represent practice neurobehavioural test bouts and shaded crosses represent analysed neurobehavioural test bouts. All conditions undertook two baseline nights with 10h TIB sleep opportunities, four 24h periods on a Fixed A, Fixed B or Rotating shift schedule with 20h TIB per 48h, and two days back on a day schedule with 10h TIB ‘recovery sleep’ opportunities.
Protocol schematics with 24h time across the x-axes. Black bars represent sleep opportunities. Grey bars represent wake time, and boxed grey bars represent on-shift periods. Unshaded crosses represent practice neurobehavioural test bouts and shaded crosses represent analysed neurobehavioural test bouts. All conditions undertook two baseline nights with 10h TIB sleep opportunities, four 24h periods on a Fixed A, Fixed B or Rotating shift schedule with 20h TIB per 48h, and two days back on a day schedule with 10h TIB ‘recovery sleep’ opportunities.

Figure 2.

Mean ± SEM per 4 8-hour period for sleep variables – total sleep time (TST), wake after sleep onset (WASO), sleep efficiency (SE), N1, N2, N3 and rapid eye movement (R). Grey bars display the Fixed A group, white bars display Fixed B and black bars are the Rotating group. Asterisks represent statistically significant differences between conditions, and asterisks with brackets represent statistically significant differences between 4 8-hour periods to BL and/or RTDS (p<0.05).
Mean ± SEM per 4 8-hour period for sleep variables – total sleep time (TST), wake after sleep onset (WASO), sleep efficiency (SE), N1, N2, N3 and rapid eye movement (R). Grey bars display the Fixed A group, white bars display Fixed B and black bars are the Rotating group. Asterisks represent statistically significant differences between conditions, and asterisks with brackets represent statistically significant differences between 4 8-hour periods to BL and/or RTDS (p<0.05).

Figure 3.

Mean ± SEM for sleep latencies during baseline and return to daytime schedule (RTDS) 4 8h periods – sleep onset latency (SOL), N2, N3 and rapid eye movement (R) latencies. Grey bars display the Fixed A group, white bars display Fixed B and black bars are the Rotating group. Asterisks represent statistically significant differences between conditions, and asterisks with brackets represent statistically significant differences between 4 8-hour periods to BL and/or RTDS (p<0.05).
Mean ± SEM for sleep latencies during baseline and return to daytime schedule (RTDS) 4 8h periods – sleep onset latency (SOL), N2, N3 and rapid eye movement (R) latencies. Grey bars display the Fixed A group, white bars display Fixed B and black bars are the Rotating group. Asterisks represent statistically significant differences between conditions, and asterisks with brackets represent statistically significant differences between 4 8-hour periods to BL and/or RTDS (p<0.05).

Figure 4.

Mean ± SEM per 48-hour period for waking function – Psychomotor Vigilance Task (PVT) Lapses, Karolinska Sleepiness Scale (KSS) and positive and negative affect. Grey bars display the Fixed A group, white bars display Fixed B and black bars are the Rotating group. Asterisks represent statistically significant differences between conditions, and asterisks with brackets represent statistically significant differences between 4 8-hour periods to BL and/or RTDS (p<0.05).
Mean ± SEM per 48-hour period for waking function – Psychomotor Vigilance Task (PVT) Lapses, Karolinska Sleepiness Scale (KSS) and positive and negative affect. Grey bars display the Fixed A group, white bars display Fixed B and black bars are the Rotating group. Asterisks represent statistically significant differences between conditions, and asterisks with brackets represent statistically significant differences between 4 8-hour periods to BL and/or RTDS (p<0.05).

Linear mixed model analyses for performance, subjective sleepiness and mood variables summed into 4 8h periods (BL, SS1, SS2, RTDS).

F-value df p
PVT Lapses
Condition 2.00 2, 21 0.160
4 8h Period 1.01 3, 63 0.392
Condition x 4 8h Period 0.53 6, 63 0.783
PVT Median Response Time
Condition 0.93 2, 21 0.410
4 8h Period 1.82 3, 63 0.152
Condition x 4 8h Period 0.33 6, 63 0.919
KSS
Condition 0.74 2, 21 0.491
4 8h Period 10.90 3, 63 <0.001*
Condition x 4 8h Period 0.80 6, 63 0.572
Positive Affect
Condition 6.28 2, 21 0.007*
4 8h Period 6.44 3, 63 0.001*
Condition x 4 8h Period 0.44 6, 63 0.847
Negative Affect
Condition 0.17 2, 21 0.841
4 8h Period 6.20 3, 63 <0.001*
Condition x4 8h Period 0.93 6, 63 0.476

Linear mixed model analyses for sleep variables summed into 4 8h periods (BL, SS1, SS2, RTDS).

F-value df p
TST (Hours)
Condition 3.20 2, 20 0.062
4 8h Period 37.02 3, 60 <0.001*
Condition x 4 8h Period 2.75 6, 60 0.020*
WASO (Mins)
Condition 5.97 2, 20 0.009*
4 8h Period 31.27 3, 60 <0.001*
Condition x 4 8h Period 2.49 6, 60 0.032*
Sleep Efficiency (%)
Condition 3.51 2, 20 0.049*
4 8h Period 38.94 3, 60 <0.001*
Condition x 4 8h Period 2.49 6, 60 0.032*
N1 (Mins)
Condition 0.19 2, 20 0.832
4 8h Period 0.39 3, 60 0.764
Condition x 4 8h Period 1.28 6, 60 0.278
N2 (Mins)
Condition 5.86 2, 20 0.010*
4 8h Period 34.38 3, 60 <0.001*
Condition x 4 8h Period 2.49 6, 60 0.032*
N3 (Mins)
Condition 0.23 2, 20 0.795
4 8h Period 5.29 3, 60 0.003*
Condition x 4 8h Period 4.01 6, 60 0.002*
Stage R (Mins)
Condition 0.06 2, 20 0.936
4 8h Period 31.47 3, 60 <0.001*
Condition x 4 8h Period 0.34 6, 60 0.913

Linear mixed model analyses for sleep onset latencies averaged into 4 8h periods for time-matched sleep opportunities (BL, RTDS).

F-value df p
Sleep Onset Latency
Condition 1.88 2, 20 0.179
4 8h Period 7.45 1, 20 0.013*
Condition x 4 8h Period 1.65 2, 20 0.217
N2 Latency
Condition 1.85 2, 20 0.184
4 8h Period 7.59 1, 20 0.013*
Condition x 4 8h Period 2.13 2, 20 0.145
N3 Latency
Condition 1.24 2, 20 0.310
4 8h Period 5.08 1, 20 0.036*
Condition x 4 8h Period 2.87 2, 20 0.080
Stage R Latency
Condition 0.65 2, 20 0.532
4 8h Period 0.72 1, 20 0.407
Condition x 4 8h Period 2.38 2, 20 0.118
eISSN:
2206-5369
Language:
English
Publication timeframe:
Volume Open
Journal Subjects:
Social Sciences, Education, other, Social Pedagogy, Social Work
Journal RSS Feed