Sleep and sleepiness among Brazilian shift-working bus drivers.

The aim of this study was to evaluate daytime and nighttime sleep, as well as daytime and nighttime sleepiness of professional shift-working bus drivers. Thirty-two licensed bus drivers were assessed by nocturnal and diurnal polysomnography (PSG) recording and multiple sleep latency testing (MSLT) sessions. Sleep length was shorter and sleep efficiency reduced during daytime sleep compared with nighttime sleep. Thirty-eight percent of the drivers had indices of obstructive apnea and hypopnea syndrome (>5/h sleep) during nighttime and daytime sleep; more drivers snored during daytime than nighttime sleep (50% vs. 35%, p < 0.05), and 38% of the drivers evidenced periodic leg movements. The MSLT revealed that 42 and 38% of the bus drivers met the criteria for sleepiness when the test was conducted during the day and night, respectively. The daytime as compared to nighttime sleep of shift-working bus drivers was shorter and more fragmented and was associated in many with evidence of excessive sleepiness. Respiratory disorder was a common finding among the professional shift-working bus drivers. All these sleep deficiencies may adversely affect on the job driving performance.