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- Matthews, Raymond W., et al.
(författare)
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Driving when distracted and sleepy : The effect of phone and passenger conversations on driving performance
- 2018
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Ingår i: Chronobiology International. - : Informa UK Limited. - 0742-0528 .- 1525-6073. ; 35:6, s. 750-753
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Tidskriftsartikel (refereegranskat)abstract
- This study investigates the effect of passenger and phone conversations on sleep-restricted driving. Six volunteers (50% male, mean age 24.8 +/- 4.3years) had their sleep restricted to 4h in bed followed by a 20-min simulated drive on three separate occasions. Each drive included either a passenger conversation, a mobile phone conversation or a quiet passenger. The effect size of a phone conversation on lane deviation was large while passenger conversation was small. The main effect of conversation on lane deviation was non-significant (F(2,10)=2.57, p=0.126). Combining sleep-restricted driving with conversations warrants further investigation.
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| 2. |
- Roach, Gregory D., et al.
(författare)
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Flat-out napping : The quantity and quality of sleep obtained in a seat during the daytime increase as the angle of recline of the seat increases
- 2018
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Ingår i: Chronobiology International. - : Informa UK Limited. - 0742-0528 .- 1525-6073. ; 35:6, s. 872-883
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Tidskriftsartikel (refereegranskat)abstract
- Some shiftwokers in the long-haul transportation industries (i.e. road, rail, sea, air) have the opportunity to sleep in on-board rest facilities during duty periods. These rest facilities are typically fitted with a seat with a maximum back angle to the vertical of 20 degrees, 40 degrees, or 90 degrees. The aim of this study was to examine the impact of back angle on the quantity and quality of sleep obtained in a seat during a daytime nap. Six healthy adults (3 females aged 27.0 years and 3 males aged 22.7 years) each participated in three conditions. For each condition, participants had a 4-h sleep opportunity in a bed (02:00-06:00 h) followed by a 4-h sleep opportunity in a seat (13:00-17:00 h). The only difference between conditions was in the back angle of the seat to the vertical during the seat-based sleep periods: 20 degrees (upright), 40 degrees (reclined), and 90 degrees (flat). Polysomnographic data were collected during all sleep episodes. For the seat-based sleep episodes, there was a significant effect of back angle on three of four measures of sleep quantity, i.e. total sleep time, slow-wave sleep, and rapid eye movement (REM) sleep, and three of four measures of sleep quality, i.e. latency to REM sleep, arousals, and stage shifts. In general, the quantity and quality of sleep obtained in the reclined and flat seats were better than those obtained in the upright seat. In particular, compared to the flat seat, the reclined seat resulted in similar amounts of total sleep and slow-wave sleep, but 37% less REM sleep; and the upright seat resulted in 29% less total sleep, 30% less slow-wave sleep, and 79% less REM sleep. There are two main mechanisms that may explain the results. First, it is difficult to maintain the head in a comfortable position for sleep when sitting upright, and this is likely exacerbated during REM sleep, when muscle tone is very low. Second, an upright posture increases sympathetic activity and decreases parasympathetic activity, resulting in a heightened level of physiological arousal.
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