Hemolysis during triathlon races: its relation to race distance.

Ninety-five triathletes were evaluated for evidence of hemolysis during triathlon races of two different distances. Thirty competitors (11 males, 19 females) were studied before and after the United States Triathlon Series (USTS) National Championship Race (1.5K swim, 40K bike, and 10K run). Pre- and post-race venous blood samples showed that 93% of the USTS athletes had decreased serum haptoglobin, post-race (mean decrease = 20%). Seven of 30 of the USTS triathletes (3 males, 4 females) were found to have occult blood in their urine, post-race. Only two of the USTS triathletes (1 male, 1 female) were anemic as judged by pre-race hemoglobin levels. Similar data were collected on 65 triatheletes (46 males, 19 females) at the Hawaii IRONMAN Triathlon World Championship (3.9K swim, 180.2K bike, and 42.2K run). Pre- and post-race venous blood samples showed that 95% of the IRONMAN athletes had decreases in serum haptoglobin, post-race (mean decrease = 32%). Occult blood was found in the post-race urine of 19 (12 males, 7 females) of the IRONMAN competitors. Nineteen IRONMAN triathletes (18 males, 1 female) were judged to be anemic from pre-race hemoglobin measurements. Data from two different length triathlons suggest that nearly all triathletes break down red blood cells during a race, and that the extent of the hemolysis is related to race distance.