The Effect of Coffee on People with High Intensity Exercise and the Characteristics of Caffeine Metabolism

The investigators will study the relationship between the impact of coffee on exercise and caffeine metabolism. The investigators will recruit healthy elite athletes. Participants will be forbidden to consume stimulant drinks such as coffee for 24 hours before the experiment. When the participants arrive at the lab on the day of the experiment, they will sign an informed consent form, a health history questionnaire and a daily coffee consumption questionnaire. Each participant does six rides, with one day of caffeine washout before each ride. In all trials, each participant will ride at the same time of day. Before riding, drink 200 ml water, decaffeinated coffee or coffee in random order, and the caffeine content of coffee is 200 mg. After 60 minutes of drinking, they start riding, after the completion of the riding, the subjects perceived and judged the perception between the baseline load and the comparison load. After the completion of the judgment, the next level of stimulus parameters will randomly generated to conduct the experiment. Each person conducted 6 groups of intervention experiments. Changes in average exercise performance, heart rate, electrocardiogram and body temperature will be observed after drinking decaffeinated coffee or coffee compared with drinking water. The concentration of caffeine and its metabolites in urine before and after drinking within 3 hours will be measured by liquid chromatography-mass spectrometry (LC-MS) or gas chromatography-mass spectrometry (GC-MS).