Daily Caffeine Intake and the Effect of Caffeine on Pilots’ Performance After Extended Wakefulness
INTRODUCTION: Fatigue is a major contributor to aviation accidents. Sufficient sleep may be difficult to achieve under operational conditions in military aviation. Countermeasures include caffeine, however, studies evaluating its effects often do not represent daily practice
with regular caffeine consumption. This study aims to establish the effect of caffeine on psychomotor performance in a realistic scenario (i.e., after a limited period of extended wakefulness).
METHODS: This randomized, double-blind, crossover, placebo-controlled trial included 30 aeromedically fit subjects. On trial days, subjects followed their normal routine till 17:00, after which caffeine intake was stopped. At midnight, subjects were given 300 mg of caffeine or placebo and performed the Psychomotor Vigilance Test, Vigilance and Tracking Test, and the Stanford Sleepiness Scale hourly up to 04:00 and again at 06:00 and 08:00. Four blood samples were collected. Statistical analyses included repeated-measures ANOVA or Friedman tests, marginal models, and Wilcoxon Signed Rank tests.
RESULTS: Median time awake at midnight was 17 h (IQR 16.5–17.5 h). Performance decreased significantly less during the night in the caffeine condition versus placebo. Neither habitual intake nor daytime caffeine consumption affected this. No statistically significant correlation was identified between blood concentrations of caffeine and performance.
DISCUSSION: A single dose of 300 mg of caffeine has beneficial effects on performance during the night in a realistic scenario for military aviation. Daytime caffeine consumption does not affect the effects of caffeine at night. These findings could be relevant for all industries in which optimal performance is required during nighttime after a limited period of extended wakefulness.
Wingelaar-Jagt YQ, Wingelaar TT, de Vrijer L, Riedel WJ, Ramaekers JG. Daily caffeine intake and the effect of caffeine on pilots’ performance after extended wakefulness. Aerosp Med Hum Perform. 2023; 94(10):750–760.
METHODS: This randomized, double-blind, crossover, placebo-controlled trial included 30 aeromedically fit subjects. On trial days, subjects followed their normal routine till 17:00, after which caffeine intake was stopped. At midnight, subjects were given 300 mg of caffeine or placebo and performed the Psychomotor Vigilance Test, Vigilance and Tracking Test, and the Stanford Sleepiness Scale hourly up to 04:00 and again at 06:00 and 08:00. Four blood samples were collected. Statistical analyses included repeated-measures ANOVA or Friedman tests, marginal models, and Wilcoxon Signed Rank tests.
RESULTS: Median time awake at midnight was 17 h (IQR 16.5–17.5 h). Performance decreased significantly less during the night in the caffeine condition versus placebo. Neither habitual intake nor daytime caffeine consumption affected this. No statistically significant correlation was identified between blood concentrations of caffeine and performance.
DISCUSSION: A single dose of 300 mg of caffeine has beneficial effects on performance during the night in a realistic scenario for military aviation. Daytime caffeine consumption does not affect the effects of caffeine at night. These findings could be relevant for all industries in which optimal performance is required during nighttime after a limited period of extended wakefulness.
Wingelaar-Jagt YQ, Wingelaar TT, de Vrijer L, Riedel WJ, Ramaekers JG. Daily caffeine intake and the effect of caffeine on pilots’ performance after extended wakefulness. Aerosp Med Hum Perform. 2023; 94(10):750–760.
Keywords: aviation; caffeine; fatigue; performance enhancement; shift work; sleep; wakefulness-promoting agents
Document Type: Research Article
Publication date: October 1, 2023
- This journal (formerly Aviation, Space, and Environmental Medicine), representing the members of the Aerospace Medical Association, is published monthly for those interested in aerospace medicine and human performance. It is devoted to serving and supporting all who explore, travel, work, or live in hazardous environments ranging from beneath the sea to the outermost reaches of space. The original scientific articles in this journal provide the latest available information on investigations into such areas as changes in ambient pressure, motion sickness, increased or decreased gravitational forces, thermal stresses, vision, fatigue, circadian rhythms, psychological stress, artificial environments, predictors of success, health maintenance, human factors engineering, clinical care, and others. This journal also publishes notes on scientific news and technical items of interest to the general reader, and provides teaching material and reviews for health care professionals.
To access volumes 74 through 85, please click here. - Information for Authors
- Submit a Paper
- Subscribe to this Title
- Membership Information
- Information for Advertisers
- Submit Articles
- Ingenta Connect is not responsible for the content or availability of external websites
Receive new issue alert- Access Key
- Free content
- Partial Free content
- New content
- Open access content
- Partial Open access content
- Subscribed content
- Partial Subscribed content
- Free trial content