Performance effects of alcohol intoxication and hangover at ground level and at simulated altitude.

Eight private pilots (four men, four women) were trained to perform on a twodimensional tracking task (joystick control of a localizer/glideslope instrument) and to respond as quickly as possible to the onset of a red pinlight, appended to the tracking instrument, by depressing a button on the joystick. Tracking and reaction time scores were obtained under both static (stationary) and dynamic conditions (during angular acceleration), at ground level and at a simulated altitude of 12,000 ft. Subjects were tested in pairs one night per week for 3 consecutive weeks (alcohol, placebo, and sleep control sessions). Sessions began at about 1700, continuing through midnight to about 1100 the next day. Subjects performed in the evening after a monitored dinner, drank prepared beverages from 2100 to midnight, and were tested again. Subjects slept 4-5 hours, were awakened around 0645, were fed, and performed the tasks again, beginning about 0730.' Ground level test sessions always preceded ascent in the altitude chamber and sessions included completion of several questionnaires and rating forms by the subjects. At midnight following alcohol ingestion (3. 25 ml of 100-proof alcohol per kg of body weight), peak breath alcohol levels averaged 91 mg percent. Impairment in tracking performance and in visual reaction time occurred during midnight sessions following alcohol ingestion. While ratings of hangover and other questionnaire data indicate awareness of hangover symptoms, no hangover-related performance impairment was recorded during morning sessions. In addition, no significant altitude/alcohol interactions on performance were obtained during either acute intoxication or hangover lneriods. These results offer no evidence contrarv to the 11 8-hour rule." 17,