Research Highlights Hazards of Extended Nighttime Driving
Extended driving at night impairs an individual's driving performance, and should, therefore, be limited, according to a research abstract presented at SLEEP 2008, the 22nd Annual Meeting of the Associated Professional Sleep Societies (APSS).
The study focused on 14 healthy young men. The participants drove in three nocturnal driving sessions (3 to 5 a.m., 1 to 5 a.m. and 9 p.m. to 5 a.m.) on an open highway. Inappropriate line crossings in the last hour of driving of each session, sleep variables, self-perceived fatigue and sleepiness were analyzed.
According to the results, compared to the 3 to 5 a.m. driving session, the incidence rate ratio of inappropriate line crossings increased by 2.6 in the 1 to 5 a.m. driving session and by 4.0 in the 9 p.m. to 5 a.m. driving session. Compared to the reference session (9 to 10 p.m.), the incidence rate ratio of inappropriate line crossings were 6.0 in the 3 to 5 a.m. driving session, 15.4 in the 1 to 5 a.m. driving session and 24.3 in the 9 p.m. to 5 a.m. driving session. Self-related fatigue and sleepiness scores were both correlated to driving impairment in the 1 to 5 a.m. and 9 p.m. to 5 a.m. driving sessions and increased significantly during the nocturnal driving sessions compared to the reference session.
"Up to now, regulations have taken into account maximal duration of driving, but the cumulative effects of sleepiness and fatigue were never studied or integrated in the driving regulation," said Pierre Philip, of Université Bordeaux in France, one of the authors of the study. "Here, we show that performance is badly affected by time of the day, and therefore, we think that a warning to limit maximum nocturnal driving duration should be included in professional safety recommendations."
It is recommended that adults get between seven and eight hours of nightly sleep.
The American Academy of Sleep Medicine (AASM) offers the following tips on how to get a good night's sleep:
- Follow a consistent bedtime routine.
- Establish a relaxing setting at bedtime.
- Get a full night's sleep every night.
- Avoid foods or drinks that contain caffeine, as well as any medicine that has a stimulant, prior to bedtime.
- Do not bring your worries to bed with you.
- Do not go to bed hungry, but don't eat a big meal before bedtime either.
- Avoid any rigorous exercise within six hours of your bedtime.
- Make your bedroom quiet, dark and a little bit cool.
- Get up at the same time every morning.