Effects of heavy drinking by maritime academy cadets on hangover, perceived sleep, and next-day ship power plant operation.

OBJECTIVE: The effects of an evening of heavy drinking on next-day occupational performance are mixed across studies and have not been investigated for ship-handling performance. Furthermore, it is not known whether the residual effects of alcohol on next-day performance are due to its effects on sleep.
METHOD: Merchant marine cadets (N=61) who had been trained on a diesel power plant simulator and who drank heavily at least episodically were given placebo beer one evening and were randomized on a second evening to placebo or real beer that resulted in a mean breath alcohol concentration (BrAC) of .115 g%. After an 8-hour sleep period, a meal, and a return to < or = .02 g% BrAC, cadets were assessed with self-report measures and the power plant simulator.
RESULTS: No effects of beverage condition were seen on actual performance, although cadets who consumed alcohol rated their performance as impaired compared with the placebo conditions. Alcohol consumption also increased the Acute Hangover Scale score, improved perceived sleep quality, and decreased perceived latency to sleep onset while not affecting perceived sleep duration.
CONCLUSIONS: While residual alcohol effects are found on some complex performance tasks, residual effects of .11 to .12 g% BrAC were not seen on ship engine simulator performance despite increased hangover symptoms and perceived impairment from the hangover. Therefore, this level of heavy drinking might not be deleterious to next-day routine occupational performance by young ship engineers despite the subjective ill effects. The perception that alcohol improves sleep onset might be a motivation for some to drink heavily. The effects on older engineers, at higher alcohol levels, and on other ship-handling tasks still need to be studied.