Wet Bulb Globe Temperature (WBGT) and the Rate of Unsuccessful Completion of a Marathon Run at a Latitude Greater than 40 Degrees

 

Marathon selection: run in a location at greater than 40 degrees latitude

 

Runner selection: non-elite regional resident, not yet fully acclimatized to a warmer temperature

 

Reasons for not completing the race:

(1) exertional heat illness

(2) dehydration

(3) overhydration with hyponatremia

(4) death

Wet Bulb Globe Temperature	Percent Unsuccessful
< 1°C	rises rapidly above 6%
1 to 13°C	around 4 to 6%
> 13°C	rises rapidly above 6%

 

percent not completing the marathon =

= ((0.514 * ((WBGT)^2)) - 8.097 * (WBGT)) + 78.926) / 10

 

Decision Level	Temperature	Percent Unsuccessful
Do Not Start	20.5°C (69°F)	13%
Caution	17°C (64°C)	9.5%

 

Limitations:

• The impact of altitude was not considered.

• This would not apply to a race run at a lower latitude or under other conditions.