The effects of increased endurance training load on biomarkers of heat intolerance during intense exercise in the heat
Lim, Chin Leong , Pyne, David , Horn, Peggy , Katz, Amelia , Saunders, Philo , Peake, Jonathan, Suzuki, Katsuhiko , Wilson, Gary , & Mackinnon, Laurel (2009) The effects of increased endurance training load on biomarkers of heat intolerance during intense exercise in the heat. Applied Physiology, Nutrition and Metabolism, 34(4), pp. 616-624.
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 degrees C) and humid (similar to 40%) conditions, until core temperature reached 39.5 degrees 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)-alpha concentrations after exercise (IL-6, 3-7 times, p < 0.01, and TNF-alpha, 33%, p < 0.01) and during recovery (IL-6, 2-4 times, p < 0.05, and TNF-alpha, 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.
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|Item Type:||Journal Article|
|Keywords:||exercise, heat stress, overload training, inflammation, endotoxemia|
|Subjects:||Australian and New Zealand Standard Research Classification > MEDICAL AND HEALTH SCIENCES (110000) > HUMAN MOVEMENT AND SPORTS SCIENCE (110600) > Exercise Physiology (110602)|
|Divisions:||Current > QUT Faculties and Divisions > Faculty of Health|
|Deposited On:||25 Oct 2012 13:34|
|Last Modified:||29 Oct 2012 09:55|
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