Table 1.

Fluid, cardiovascular, metabolic, and thermal variables

Trials
EU + WEU + NW HY + W HY + NW
Ad libitum water intake, liters 0.31 ± 0.11 01.65 ± 0.18 0
ΔBody mass during HST, %−1.0 ± 0.2 −1.4 ± 0.1+0.9 ± 0.21-a , 1-b −1.5 ± 0.11-a , 1-c
Total Δbody mass,1-d % −1.0 ± 0.2 −1.4 ± 0.1−3.0 ± 0.21-e −5.1 ± 0.21-e
Final HR, beats/min129 ± 6 133 ± 6 128 ± 4152 ± 61-e
o 2, ml ⋅ kg−1 ⋅ min−1 20.3 ± 0.4 19.9 ± 0.6 21.1 ± 0.521.2 ± 0.5
Aerobic heat production, W/m2 210.8 ± 5.7 202.4 ± 8.1 209.2 ± 8.2210.0 ± 8.0
Total sweat loss, kg0.96 ± 0.04 0.94 ± 0.04 0.96 ± 0.051.01 ± 0.05
Evaporative heat loss, W/m2 159.9 ± 6.1 155.3 ± 5.4 159.5 ± 8.7168.7 ± 8.4
Radiative heat loss, W/m2 8.6 ± 1.0 7.1 ± 1.8 6.5 ± 1.99.6 ± 1.6
Sweat rate, g ⋅ m−2 ⋅ h−1 338 ± 13 329 ± 12 338 ± 20357 ± 19
Heat storage, W/m2 24.1 ± 3.5 24.1 ± 3.5 17.2 ± 4.132.9 ± 3.01-e
Final Tre, °C38.0 ± 0.1 38.1 ± 0.1 38.2 ± 0.239.1 ± 0.11-e
ΔTre, °C+0.9 ± 0.1 +1.0 ± 0.1 +1.0 ± 0.1+1.8 ± 0.11-e
Final Embedded Image °C35.1 ± 0.2 34.7 ± 0.4 34.6 ± 0.335.1 ± 0.3
  • Values are means ± SE; n = 10. EU, euhydration; HY, hypohydration; W, water ad libitum; NW, no water;V˙o 2, O2consumption; HR, heart rate; Δ, change during 90-min exercise bout; Tre, rectal temperature; Embedded Image mean weighted skin temperature; HST, 90-min heat stress test.

  • F1-a Significantly different from EU + W (P < 0.05–0.001);

  • F1-b significantly different from EU + NW (P < 0.001);

  • F1-c significantly different from HY + W (P < 0.025–0.001);

  • F1-d during entire protocol;

  • F1-e significantly different from all other treatments (P < 0.05–0.0001).