Young men figure prominently in sleep-related road crashes. Non-driving studies show them to be particularly vulnerable to sleep loss, compared with older men. The authors assessed the effect of a normal night's sleep vs. prior sleep restricted to 5h, in a counterbalanced design, on prolonged (2h) afternoon simulated driving in 20 younger (av. 23y) and 19 older (av. 67y) healthy men. Driving was monitored for sleepiness related lane deviations, EEGs were recorded continuously and subjective ratings of sleepiness taken every 200s. Following normal sleep there were no differences between groups for any measure. After sleep restriction younger drivers showed significantly more sleepiness-related deviations and greater 4-11Hz EEG power, indicative of sleepiness. There was a near significant increase in subjective sleepiness. Correlations between the EEG and subjective measures were highly significant for both groups, indicating good self-insight into increasing sleepiness. The authors confirm the greater vulnerability of younger drivers to sleep loss under prolonged afternoon driving. (Author/publisher)
Abstract