The experimental trials were performed @ min after ingesting CP ( @ g of carbohydrate , @ mg caffeine ) or CC ( @ g carbohydrate , @ mg caffeine ) , and heart rate ( HR ) , oxygen consumption ( VO@ ) , carbon dioxide production , minute ventilation ( VE ) , respiratory-exchange ratio ( RER ) , rating of perceived exertion ( RPE ) , gastrointestinal discomfort ( GI ) , and thirst perception ( Thirst ) were recorded every @ m. Blood lactate -LSB- La - -RSB- was recorded immediately before and after exercise .