Work schedules, sleep patterns, temperature rhythm in long distance bus drivers

JOAQUÍN DIEZ; DANIEL E. VIGO; DANIEL PÉREZ CHADA; MAURO BRANGOLD; DIEGO GOLOMBEK; DANIEL P. CARDINALI

Congreso; 26 th Annual Meeting of the Associated Professional Sleep Societies; 2012

Introduction: Long distance drivers in Argentina usually cover very long journeys without enough time to rest, alternating with a partner. Resting conditions during the journey are precarious limiting the time and quality of their sleep. Methods: A sample of 84 long-distance bus drivers (all males) was selected. Wrist actigraphy and skin temperature were recorded during 7 days. Total sleep time (TST), sleep ?during the trip? (SDT), sleep ?in a bed? (SIB) and trip/total sleep ratio (TTR) were computed as well as temperature mesor, acrophase, amplitude and percentage of rhythm variance (FTV). The sample was divided in two groups according to trip duration: A: 15 to 17 hours, and B: 9 to 11 hours. Actigraphic and temperature data were compared by t test for independent paired samples. Values are expressed as mean ± standard error. Results: Age and body mass index did not differ between groups. Sleep patterns did not differ in the time slept ?in a bed? (271 ± 12 min). Subjects in schedule A had higher values of TST (A: 467 ± 26 min vs. B: 358 ± 33 min; p = 0.026), SDT (A: 204 ± 24 min vs. B: 106 ± 16 min; p = 0.012) and TTR (A: 0.41 ± 0.03 vs. B: 0.22 ± 0.03; p = 0.002) when compared to schedule B drivers. The latter revealed lower mesor (B: 32.92 ± 0.13 C° vs. A: 33.45 ± 0.09 C°; p = 0.001), higher amplitude (B: 0.66 ± 0.06 C° vs. A: 0.38 ± 0.04 C°; p < 0.001) and higher FTV (B: 35.30 ± 3.14% vs. A: 18.56 ± 2.11%; p < 0.001) than group A. Acrophase was similar in both groups. Conclusions: Longer work schedules where associated to lower temperature amplitude and rhythm strength and a higher proportion of sleep during the trip.