Water only is an appropriate pre-exercise beverage for: exercise lasting less than 60 minutes exercise lasting from 1 to 4 hours or greater than 4 hours exercise lasting from 1 to 4 hours exercise indoors in a air-conditioned environment. exercise lasting greater than 4 hours Based on research it is now suggested that CAFFEINE intakes below ______ mg/d will likely have no negative effect on fluid or electrolyte balance. 32 oz of pepsi/diet pepsi 450 mg/d 350 mg/d 300 mg/d 16 oz regular coffee