Hematocrits of triathletes: is monitoring useful?

Journal Article (Journal Article)

PURPOSE: The purpose of this manuscript was to provide a basis for establishing safety cutoffs for hematocrit levels in triathletes and background data for possible future medical control regulations. METHODS: Competitors from three different distance triathlons participated: Olympic (N = 118), half-Ironman (N = 87), and Ironman (N = 207). Blood samples were drawn within 24-36 h prerace (N = 412) and within minutes of race finish (N = 296). Prerace hematocrits approximated a normal distribution for men (X = 43.2 +/- 2.9) and women (X = 40.2+/-2.6). Prerace hematocrits decreased as competitive distance increased for men (X = 45.0, 43.4, 42.5; respectively; P < 0.01) but not for women (P > 0.05). RESULTS: Mean race day changes were small but statistically significant for Olympic and Ironman men and for half-Ironman women. Individual responses were more variable with hemoconcentration occurring in 57%, hemodilution in 43%, and no change in 2% of participants. The magnitude of individual responses was also variable with hematocrit changes ranging from -7.1 to + 10%. No athlete in this sample had a hematocrit that would place him/her in the "danger zone" (Hct > 55%). CONCLUSIONS: Cutoff values (3 SD above the means) of 52% for men and 48% for women are suggested by these data. However, the relationship of these cutoffs to either athlete safety or the ability to detect rules violations remains unknown.

Full Text

Duke Authors

Cited Authors

  • O'Toole, ML; Douglas, PS; Hiller, WD; Laird, RH

Published Date

  • March 1999

Published In

Volume / Issue

  • 31 / 3

Start / End Page

  • 372 - 377

PubMed ID

  • 10188740

International Standard Serial Number (ISSN)

  • 0195-9131

Digital Object Identifier (DOI)

  • 10.1097/00005768-199903000-00004


  • eng

Conference Location

  • United States