Determining a "Do Not Start" Temperature for a Marathon on the Basis of Adverse Outcomes

Abstract

Marathons in northern latitudes (>40 degrees) held in "unexpectedly" hot conditions when the participants are not acclimatized and the start WBGT is >21 degrees C often end in either race cancellation or an MCI. It would seem prudent not to start these races in similar conditions. The rate of unsuccessful marathon starters per 1000 marathon finishers plotted against start WBGT generates a curve that can be used to estimate a do not start level. The do not start WBGT for Twin Cities Marathon is 20.5 degrees C on the basis of this model.