How much caffeine is allowed during an ultramarathon?
                                
                                
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                                    3 min read                                
                            
                                According to the International Society of Sports Nutrition, consuming 3–6 mg of caffeine per kilogram of body weight can improve endurance performance by 2–4%. For ultramarathoners, understanding how much caffeine is allowed during an ultramarathon is critical for managing fatigue and improving focus in the later stages of a race.