The objective of this study was to determine the yield of exercise stress testing (GXT) and other methods for evaluating candidates for HAZMAT duty.
The authors conducted an analysis of prior and current records of GXTs, medical examinations, blood tests, chest radiographs, spirometry, and audiometry in 190 candidates. The authors also conducted scrutiny of GXT results, using Duke Treadmill Score (DTS), Chronotropic Index (CI), and Heart Rate Recovery (HRR).
Seven candidates were disapproved by history and/or physical examination. Twenty-one others were deferred for GXT-induced, marked hypertension, and/or ST depression ≥2 mm. The latter appeared to be false-positive indications of ischemia, low risks confirmed by DTS, CI, and HRR. Heat stress was not induced in 26 subjects so evaluated.
GXT identified marked hypertension in 12 HAZMAT candidates and ischemic ST changes in 10, the latter appearing to be false-positives. Other testing yielded useful baselines, rarely disqualifying.