ABSTRACT
Introduction ............................................................................................................ 272 What Is Caffeine? .............................................................................................. 272 Where Does It Come From? ............................................................................. 272 How Does It Act on the Body?.......................................................................... 272 How Much Can We Have? ................................................................................ 273 What External Factors Affect Its Metabolism? ................................................. 273
Behavioral Effects of Acute Caffeine Ingestion ..................................................... 273 A ProŠle of the Effects of Caffeine on Mood and Cognitive Performance ...... 273 Caffeine and Physical Performance .................................................................. 274
Mechanisms Underlying the Behavioral Effects of Caffeine................................. 275 Reversal of Impairments Due to Low Levels of Arousal ....................................... 277
Sleep Deprivation .............................................................................................. 277 Maintenance of Wakefulness Test (MWT) and Multiple Sleep Latency Test (MSLT) ................................................................................................. 277 Performance and Subjective Alertness ......................................................... 277
A Review of Randomized Trials of Caffeine and Cognitive Performance ....... 279 Caffeine and Circadian Troughs ........................................................................ 279
Night Work ................................................................................................... 279 Postlunch Dip ............................................................................................... 279 Early Morning .............................................................................................. 279 Evening ......................................................................................................... 279
Caffeine and Sustained Work ............................................................................280 Sustained Military Operations...........................................................................280
