Caffeine is a known ergogenic (i.e. performance-enhancing) substance used by many athletes participating in various disciplines. But does it work for all types of exercise? What are the mechanisms behind caffeine and performance? How does it impact health? Caffeine as a supplement Caffeine is an alkaloid present in plants such as coffee that acts as an stimulant. The form commonly used as a sports supplement is called anhydrous caffeine and comes in various presentations, including pills, powders, gums, gels and liquids. It can also be consumed in the form of coffee or tea, although this makes it difficult to figure the exact amount of the active compound. Endurance sports Researchers…