Jet Lag in Military Operations: Field Trial of L-Tryptophan in Reducing Sleep-Loss Effects

Abstract : The conduct of military operations may involve rapid deployment across multiple time zone, altered work-rest schedules, and performance under conditions of sleep loss. We evaluated the sleep-promoting effects of the amino acid 1-tryptophan in the field in this study of the acute effects of rapid deployments on performance. Subjects were 51 Marines (age 21 + or - 2.2 years) airlifted from California to Okinawa. Physiological data were obtained from 12 subjects using Medilog recorders. Subjective measures included analog mood scales, the Standford Sleepiness Scale, and the Profile of Mood States. Performance measures included 4-choice reaction time, and the Digit Symbol Substitution Test (DSST). Baseline data were collected 2 weeks prior to deployment on 3 consecutive days, on the 2 days immediately prior to the flight, the day of flight, and 2 days after arrival. Target shooting performance was assessed one week prior to departure and on 01, both sessions at 0800 LT. L- tryptophan 2g or placebo was administered en route on the first 3 nights in Okinawa. To maximize sleep during flight, environmental interventions included timing of meals and other inflight activities, elimination of caffeine, and control of cabin lighting. Acute jet lag effects were assessed by comparing data for B3, 01, and 02 at 0900, 1500, and 2100 LT by ANOVA for repeated measures. Post-hoc t-tests were used to identify sources of significant effects. For target shooting, factors were G and D. Between groups t-tests were used to compare total sleep for 1-tryptophan and placebo subjects.