Background: The purpose was to: 1) correlate and compare the long Environmental Symptoms Questionnaire (56-ESQ) with markers of heat acclimation; 2) compare the 56-ESQ with a modified version of the ESQ (14-ESQ) over a 10-d exercise heat acclimation protocol; 3) correlate both scales with physiological data; and 4) determine those questions most sensitive to heat acclimation responses to further refine the 14-ESQ. This is reported as a 12-question ESQ (12-ESQ), which was correlated with physiological data.
Methods: There were 10 non-trained, non-heat-acclimatized men (age 20 +/- 1 yr; height 184 +/- 8 cm; weight 81.7 +/- 12.2 kg; percent body fat 10.1 +/- 2.9%) who undertook 10 consecutive days of heat acclimation (walking at 5.6 km x h(-1), 5% grade, 90 min duration; 33 degrees C, 30-50% relative humidity). ESQ forms were completed on days 1, 4, 7, and 10 pre- and post-exercise. During exercise, rectal temperature (T(r)), heart rate (HR), and rating of perceived exertion (RPE) were recorded.
Results: Verification of heat acclimation was based on T(r) and HR, which were significantly lower on day 4 (38.11 +/- 0.25 degrees C, 143 +/- 13 bpm) vs. day 1 (38.46 +/- 0.47 degrees C, 158 +/- 17 bpm) and all subsequent days. All ESQ scales demonstrated a significant effect of time, supporting evidence of heat acclimation. The 56-, 14-, and 12-ESQ post-exercise scores were significantly correlated with HR (r2 = 0.424, 0.353, and 0.430, respectively). The 12-ESQ was correlated with T(r) (r2 = 0.400).
Discussion: The 12- and 14-ESQ tracked well with the 56-ESQ. All ESQs were able to track physiological variables and symptoms of heat stress. All ESQ forms may be used as an efficient method to indicate environmental heat stress and symptoms.