Sleep patterns, temperature rhythm, alertness, heart rate variability, and work schedules in long distance bus drivers

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

Congreso; XII Latin American Symposium on Chronobiology; 2013

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 184 long-distance bus drivers (all males) was assessed. 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. Alertness and automomic activity during the trip were measured using the Psychomotor Vigilance Task (PVT) and Heart Rate Variability (HRV) respectively. Values are expressed as mean ± standard error. Results: Weight disorders (90%), smoking (37%) and physical inactivity (54%) were highly prevalent. Globally, drivers presented irregular sleep patterns. When averaging sleep time on a daily basis, an average of 439 ± 14 min of TST, 280 ± 8 min of SIB, 161 ± 11 min of SDT, and 0.35 ± 0,02 of TTR was observed. However, HRV pattern in SDT was compatible with relaxation rather than sleep. In longer driving schedules (15-17hours) TST, SDT and TTR where higher, while temperature amplitude and ryhthm strength were lower than shorter trips (9-11hours). Reaction time in PVT showed a slowdown at the end of return trips. Conclusions: Long distance bus drivers have a high prevalence of cardiovascular risk factors, irregular sleep schedules, circadian disruption, and decrease in alertness.