Table 2.
Tolerance time (mean, range) and termination criteria across the different environmental conditions and work rates (n = 12).
| WBGT (°C) | Speed (km·h−1) | Tolerance time (min) | HR (>90% max) | T c (>39°C) | Fatigue or nausea | Duration (=60 min) |
|---|---|---|---|---|---|---|
| 21 | 2.5 | 52.1 (27.5–60)b,c | 4 | 8 | ||
| 4 | 36.0 (18–53)b | 8 | 1 | 3 | ||
| 5.5 | 20.4 (6.5–39) | 11 | 1 | |||
|
| ||||||
| 30 | 2.5 | 39.1 (18.5–51.5)a,b,c | 9 | 2 | 1 | |
| 4 | 27.4 (12–47.5)b | 11 | 1 | |||
| 5.5 | 16.9 (9–28.5) | 12 | ||||
|
| ||||||
| 37 | 2.5 | 33.5 (13.5–44.5)a,b,c,d | 8 | 1 | 3 | |
| 4 | 24.7 (9–33)a,b | 11 | 1 | |||
| 5.5 | 15.1 (6–25.5) | 11 | 1 | |||
Values are mean (range). Main effect observed for environment (WBGT37 < WBGT30 < WBGT21; P < 0.001), work intensity (5.5 < 4 < 2.5 km·h−1; P < 0.001), and their interaction (P < 0.001). WBGT, wet bulb globe temperature; HR, heart rate; T c, core temperature. aSignificantly different to the same speed at WBGT 21°C (P < 0.05); bsignificantly different to 5.5 km·h−1 at the same environmental condition (P < 0.05); csignificantly different to 4 km·h−1 at the same environmental condition (P < 0.05); dsignificantly different to the same speed at WBGT 30°C (P < 0.05).