Heat stress and flame protective clothing in mine rescue brigadesmen: inter- and intraindividual variation of strain.

A climatic exposure was conducted for the 52 rescue brigadesmen of a mine while they wore flame protective clothing. We looked for individual parameters allowing prediction of tolerated exposure times in the climate tested. Of all individual parameters, only body temperature at the end of the Stoklossa heat tolerance test and physical fitness showed significant influence on the tolerated exposure time, although not very strongly. Age, body mass, and Body Mass Index showed no significant influence on the tolerated exposure time. It was found during a longitudinal study that the tolerance time within the climate for four subjects showed considerable variations, and so it was decided neither to take the result of the heat tolerance test as admittance criterion for the mine rescue service nor to perform a ranking of brigadesmen with respect to heat tolerance by this test.