Table 1.
Baseline Characteristics of Study Participants and Their Exertional Heat–Related Events
| Variable |
Exertional Heat Stroke (n = 21) |
Exertional Heat Illness (n = 165) |
||||
| HTT ≤6 wk (n = 12) |
HTT >6 wk (n = 9) |
P Value |
HTT ≤6 wk (n = 94) |
HTT >6 wk (n = 71) |
P Value |
|
| Time to HTT, mean ± SD, d | 32 ± 9.6 | 64.2 ± 17.1 | <.01 | 27.5 ± 8.9 | 79.1 ± 58 | <.01 |
| Age, mean ± SD, y | 19.3 ± 1.1 | 21.3 ± 3.9 | .17 | 19.9 ± 1.2 | 19.8 ± 1.5 | .57 |
| Height, mean ± SD, cm | 173.6 ± 7.1 | 172 ± 8.9 | .67 | 174.8 ± 6.7 | 174.7 ± 6.3 | .98 |
| Weight, mean ± SD, kg | 71.9 ± 11.5 | 71.6 ± 12.8 | .95 | 71.7 ± 11.7 | 72.7 ± 13.3 | .63 |
| Body mass index, mean ± SD, kg/m2 | 23.8 ± 3 | 24.7 ± 3.5 | .54 | 23.4 ± 3.3 | 23.8 ± 4 | .56 |
| Rectal temperature, mean ± SD (95% confidence interval), °C | 40.8 ± 0.7 (40.4, 41.2) | 40.8 ± 0.9 (40.2, 41.4) | .99 | 38.7 ± 0.7 (38.6, 38.8) | 38.8 ± 0.6 (38.7, 38.9) | .31 |
| Neurologic symptoms, No. (%) | ||||||
| Mild | 4 (33) | 2 (22) | .73 | 34 (36) | 27 (38) | .98 |
| Moderate | 6 (50) | 4 (45) | 43 (46) | 31 (44) | ||
| Severe | 2 (17) | 3 (33) | 17 (18) | 13 (18) | ||
| Laboratory abnormalities, No. (%)a | ||||||
| Mild | 5 (50) | 5 (56) | .70 | 71 (82) | 54 (81) | .46 |
| Moderate | 1 (10) | 2 (22) | 11 (13) | 6 (9) | ||
| Severe | 4 (40) | 2 (22) | 5 (5) | 7 (10) | ||
| Type of activity, No. (%) | ||||||
| Field training | 1 (8) | 0 | .88 | 11 (12) | 4 (6) | .03 |
| Krav Maga | 0 | 0 | 3 (3) | 2 (3) | ||
| March | 4 (33) | 2 (22) | 53 (56) | 39 (55) | ||
| Operational activity | 0 | 0 | 0 | 1 (1) | ||
| Selections | 0 | 1 (11) | 7 (7) | 16 (23) | ||
| Performance testing | 7 (59) | 6 (67) | 20 (22) | 9 (12) | ||
| Treatment, % delayedb | 25 | 33 | 1 | 49 (53) | 38 (54) | 1 |
Abbreviation: HTT, heat-tolerance testing.
a
Missing enzymes data for 2 participants in the exertional heat-stroke group.
b
Delayed initiation of the cooling protocol by >30 minutes since the first sign of the exertional heat illness.