Reflections on a 100-mile Run: Effects of Aspirin Therapy

I finished a 100-mile competitive run in hot, humid weather. Because of knee pain, I took therapeutic amounts of aspirin before and throughout the race. Based on empirical evidence, I conclude that aspirin increased by sweat rate, body temperature, and urinary output; inhibited my thirst; abolished my knee pain; and blunted my sense of fatigue. The overall effect was detrimental and predisposed me to heat illness. From the information presented, two potential effects of aspirin have become evident. First, aspirin therapy (approximately 10 or more tablets daily) may be dangerous when combined with physical exertion in the heat. Second, aspirin therapy might reduce the extreme thirst sometimes associated with hyperreninemia. Both hypotheses deserve further study.