The Effect Of Caffeine On Work Output And Fatigue In Rats

Abstract

Caffeine is a drug commonly found in the diets of most human cultures. Its source in the US diet is coffee (1 part caffeine to 15 parts coffee), tea (1 part to 48 parts), and cola nuts (2.7 parts to 3.6 parts). Less known, but still in considerable use are mati (1.5 parts to 2 parts), and juarana (3 parts to 5 parts), used in the preparation of some teas (7, 29). It is estimated that US consumption of coffee alone is in excess of 2.5 billion pounds per year (7). Caffeine is known to affect the central nervous system, myocardium, skeletal muscles, smooth muscles of the bronchii and blood flow. In addition it induces diuresis. It is also used in the diagnosis of some illnesses. Caffeine is often used theraputically (28,29). Its side effects include nausea, insomnia, restlessness, and muscle tremors. Because caffeine's main action is on the heart, central nervous system and the skeletal musculature, it affects exercise and recovery from exercise. The purpose of this work is to study the effect of caffeine in vivo on work output and fatigue.