TY - JOUR
T1 - The effects of increased endurance training load on biomarkers of heat intolerance during intense exercise in the heat
AU - Lim, Chin Leong
AU - Pyne, David
AU - Horn, Peggy
AU - Kalz, Amelia
AU - Saunders, Philo
AU - Peake, Jonathan
AU - Suzuki, Katsuhiko
AU - Wilson, Gary
AU - Mackinnon, Laurel T.
PY - 2009/8
Y1 - 2009/8
N2 - The effects of increased training (IT) load on plasma concentrations of lipopolysaccharides (LPS), proinflammatory cytokines, and anti-LPS antibodies during exercise in the heat were investigated in 18 male runners, who performed 14 days of normal training (NT) or 14 days of 20% IT load in 2 equal groups. Before (trial 1) and after (trial 2) the training intervention, all subjects ran at 70% maximum oxygen uptake on a treadmill under hot (35 °C) and humid (*40%) conditions, until core temperature reached 39.5 °C or volitional exhaustion. Venous blood samples were drawn before, after, and 1.5 h after exercise. Plasma LPS concentration after exercise increased by 71% (trial 1, p < 0.05) and 21% (trial 2) in the NT group and by 92% (trial 1, p < 0.01) and 199% (trial 2, p < 0.01) in the IT group. Postintervention plasma LPS concentration was 35% lower before exercise (p < 0.05) and 47% lower during recovery (p < 0.01) in the IT than in the NT group. Anti-LPS IgM concentration during recovery was 35% lower in the IT than in the NT group (p < 0.05). Plasma interleukin (IL)-6 and tumor necrosis factor (TNF)-α concentrations after exercise (IL-6, 3-7 times, p < 0.01, and TNF-α, 33%, p < 0.01) and during recovery (IL-6, 2-4 times, p < 0.05, and TNF-α, 30%, p < 0.01) were higher than at rest within each group. These data suggest that a short-term tolerable increase in training load may protect against developing endotoxemia during exercise in the heat.
AB - The effects of increased training (IT) load on plasma concentrations of lipopolysaccharides (LPS), proinflammatory cytokines, and anti-LPS antibodies during exercise in the heat were investigated in 18 male runners, who performed 14 days of normal training (NT) or 14 days of 20% IT load in 2 equal groups. Before (trial 1) and after (trial 2) the training intervention, all subjects ran at 70% maximum oxygen uptake on a treadmill under hot (35 °C) and humid (*40%) conditions, until core temperature reached 39.5 °C or volitional exhaustion. Venous blood samples were drawn before, after, and 1.5 h after exercise. Plasma LPS concentration after exercise increased by 71% (trial 1, p < 0.05) and 21% (trial 2) in the NT group and by 92% (trial 1, p < 0.01) and 199% (trial 2, p < 0.01) in the IT group. Postintervention plasma LPS concentration was 35% lower before exercise (p < 0.05) and 47% lower during recovery (p < 0.01) in the IT than in the NT group. Anti-LPS IgM concentration during recovery was 35% lower in the IT than in the NT group (p < 0.05). Plasma interleukin (IL)-6 and tumor necrosis factor (TNF)-α concentrations after exercise (IL-6, 3-7 times, p < 0.01, and TNF-α, 33%, p < 0.01) and during recovery (IL-6, 2-4 times, p < 0.05, and TNF-α, 30%, p < 0.01) were higher than at rest within each group. These data suggest that a short-term tolerable increase in training load may protect against developing endotoxemia during exercise in the heat.
KW - Anti-LPS antibodies
KW - Cytokines
KW - Endotoxemia
KW - Heat tolerance
KW - Lipopolysaccharides
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U2 - 10.1139/H09-021
DO - 10.1139/H09-021
M3 - Article
C2 - 19767796
AN - SCOPUS:70349916666
SN - 1715-5312
VL - 34
SP - 616
EP - 624
JO - Applied Physiology, Nutrition and Metabolism
JF - Applied Physiology, Nutrition and Metabolism
IS - 4
ER -
