2007, Piran, Slovenia

Environmental Ergonomics XII
Igor B. Mekjavic, Stelios N. Kounalakis & Nigel A.S. Taylor (Eds.), © BIOMED, Ljubljana 2007
Table 2. Peak Tau and RPE during R1-R3, and IL-6 response and change (∆) postexercise
in the CG and PSG; one PSG subject declined phlebotomy (N=18).
Variable Group R1 R2 R3
Peak Tau (°C)
CG (N = 8)
PSG (N = 10)
38.29 [0.57]
38.60 [0.32]
38.38 [0.67]
38.68 [0.48]
38.53 [0.45]
38.77 [0.49]
Peak RPE
CG (N = 8)
PSG (N = 10)
16 [2]
16 [2]
16 [2]
16 [2]
17 [2]
17 [2]
IL-6 Post CG (N = 8) 14.15 [4.65] 15.02 [5.82] 16.88 [5.21]
(pg/mL) PSG (N = 9) 14.96 [5.40] 17.76 [7.87] 14.78 [5.17]
∆ IL-6 (pg/mL)
CG (N = 8)
PSG (N = 9)
7.21 [4.46] 6.52 [4.79] 8.68 [4.99]
7.50 [5.36] 9.12 [7.00] 6.59 [4.76]
In the PSG, average peak Tau was reached in minute 79 [12] in R1, minute 82 [15] in
R2 and minute 81 [10] in R3 (Figure 1). VO2 at 80 minutes indicated that the PSG
subjects were working at an average [SD] of 58 [14]% of their VO2max in R1, 70
[16]% in R2 and 72 [10]% in R3 (P>0.05).
126
∆ Tau(°C)
2.50
2.00
1.50
1.00
0.50
0.00
R1 R2 R3
0 15 30 45 60 75 90
Time (min)
Figure 1: ∆Tau in R1-R3 in the PSG; Tau peaked after the 75 th minute of exercise (N =
10)
DISCUSSION
PST increases the distance that individuals can run in the heat. This finding extends
the benefit provided by PST in stressful environments from cold water (Barwood et
al, 2006) to hot air. It is not possible to say what about the provision of PST makes it
work; it could be one of the interventions, the combination or something as simple as
additional exposure to the experimenters. Whatever the mechanism, in the present
study PST improved performance by enabling subjects to run faster with high deep
body temperatures and RPE scores; the hypothesis is therefore accepted. These
findings have important implications for studies that employ unblinded interventions.