Time course of mean Tc response of 7 lean and 7 obese 9- to 12-yr-old boys during repeated exercise-heat bouts in the summer months. Exercise at 30% V˙o2max alternated between a treadmill and bike for 3 20-min bouts interspersed with 5-min rest periods at 38°C and 50% rh. Values are means ± SE. Bas, Baseline; Rec, Recovery. A (lean boys Tc, day 1 and day 6) and B (lean boys Tc, all 6 days): *P < 0.001 between day 1 and day 6 for lean boys. C (obese boys Tc, day 1 and day 6) and D (obese boys Tc, all 6 days): ‡P < 0.001 between day 1 and day 6 for obese boys.