Caffeine maintains vigilance and marksmanship in simulated urban operations with sleep deprivation

Aviat Space Environ Med. 2005 Jan;76(1):39-45.


Purpose: The purpose of this study was to examine the effects of caffeine (CAF) on physical, vigilance, and marksmanship tasks in soldiers during a sustained 55-h field exercise.

Methods: There were 30 soldiers (23.6 +/- 4.5 yr, 81.8 +/- 10.3 kg) who were divided into a placebo (PLAC) and a CAF group. After a period of restricted sleep of 3 h during the first night, a period of sustained wakefulness began that ended at 11:00 of the third day. PLAC or CAF doses of 100 mg, 200 mg, 100 mg, and 200 mg were administered at 21:45, 23:45, 01:45, and 03:45, respectively. At 22:00 of day 2, subjects began two cycles of marksmanship, urban operations vigilance, and psychomotor vigilance (PVT) testing which ended at 06:00 of day 3.

Results: CAF maintained marksmanship vigilance at 85% throughout the second night as compared with PLAC, who significantly declined to 61.4 +/- 28.2% overnight. Marksmanship accuracy also decreased significantly in PLAC from 95.1 +/- 8.3% to 83.3 +/- 19.2%, but no change was observed in CAF. Urban operations vigilance decreased for both groups over the night, but the decrease was less for CAF (81.2 +/- 14.4% to 63.4 +/- 24.1%) compared with PLAC (77.6 +/- 19.2% to 44.0 +/- 30.2%). Reaction time and the number of major and minor lapses with the PVT significantly increased in PLAC but were unaffected in CAF.

Conclusions: It was concluded that CAF was an effective strategy to sustain vigilance and psychomotor performance during military operations involving sleep deprivation.

Publication types

  • Clinical Trial
  • Controlled Clinical Trial

MeSH terms

  • Adult
  • Caffeine / therapeutic use*
  • Central Nervous System Stimulants / therapeutic use*
  • Double-Blind Method
  • Firearms*
  • Humans
  • Male
  • Military Personnel*
  • Psychomotor Performance / drug effects*
  • Running
  • Sleep Deprivation / drug therapy*
  • Task Performance and Analysis
  • United States


  • Central Nervous System Stimulants
  • Caffeine