Two environmental symptoms questionnaires during 10 days of exercise-heat acclimation

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.

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.

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).

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.