Does caffeine affect endurance?

Caffeine’s role in endurance is less about a 'metabolic boost' and more about psychological and neurological regulation. While early theories suggested caffeine improved performance by increasing fat oxidation and sparing muscle glycogen, modern consensus points to the central nervous system as the primary site of action. By antagonizing adenosine receptors in the brain, caffeine blunts the perception of fatigue and pain, effectively lowering the rating of perceived exertion (RPE). This allows an athlete to push harder for longer because the brain perceives the effort as less taxing than it would be in a non-caffeinated state. For the coffee producer, this highlights the value of the bean as a complex delivery system. Unlike synthetic caffeine pills, coffee contains a matrix of polyphenols and chlorogenic acids that may influence how the body processes the stimulant. Producers often focus on the 'cleanliness' of the cup, but from a physiological standpoint, the variability in caffeine content—ranging from 75mg to over 150mg per cup depending on roast profile and origin—means that athletes using coffee as a performance aid face a challenge in dosing consistency. A common misconception is that more is better; however, research indicates that once a threshold of 6 mg/kg is reached, additional consumption offers no further performance advantage and may introduce gastrointestinal distress. For the farmer, this underscores the importance of consistent processing and drying, as these factors dictate the chemical stability of the final product, which ultimately serves as a functional tool for the athlete.