The Navy SEAL Physical Fitness Guide - Uniformed Services ...

" CaffeineThis section will discuss only those agents which are illegal and can produceharmful effects.AmphetaminesOne class of stimulants is the Amphetamines. The term amphetamine also includesmethylamphetamine, dimethyl-amphetamine, and benzylamphetamine which aremetabolized to amphetamine after ingestion. In the 1960's, these drugs were widely usedby athletes in the belief that they improved strength and endurance. Stimulants such asamphetamines and many over-the-counter amphetamine “look alikes” have pronouncedeffects throughout the body. Taking these agents will result in the physiologic andpsychological effects noted in Table 13-4 and Table 13-5. As can be seen, these effects arethe same ones which occur normally without stimulants when you are asked to undertakedangerous missions.Table 13-4. Reported Physiologic Effects ofAmphetaminesIncreases heart rateIncreases cardiac outputElevates blood pressureIncreases conversion of glycogen to glucoseElevates serum glucoseElevates serum free fatty acidsDilates blood vessels in musclesConstricts blood vessels in the skinIncreases muscle cell excitabilityAmphetamines can mask symptoms of fatigue. They may restore reaction time in aweary athlete, but cannot improve reaction time or diligence in a well rested and motivatedathlete. The potential beneficial effect is most marked when performance is reduced byfatigue or lack of sleep.The Navy SEAL Physical Fitness Guide 229