The purpose of this study was to compare the effects of exercise intensity and exercise-induced muscle damage on changes in anti-inflammatory cytokines and other inflammatory mediators. Nine well-trained male runners completed three different exercise trials on separate occasions: (1) level treadmill running at 60% VO2max (moderate-intensity trial) for 60 min; (2) level treadmill running at 85% VO2max (high-intensity trial) for 60 min; (3) downhill treadmill running (-10% gradient) at 60% VO2max (downhill running trial) for 45 min. Blood was sampled before, immediately after and 1 h after exercise. Plasma was analyzed for interleukin-1 receptor antagonist (IL-1ra), IL-4, IL-5, IL-10, IL-12p40, IL-13, monocyte chemotactic protein-1 (MCP-1), prostaglandin E(2), leukotriene B(4) and heat shock protein 70 (HSP70). The plasma concentrations of IL-1ra, IL-12p40, MCP-1 and HSP70 increased significantly (P<0.05) after all three trials. Plasma prostaglandin E(2) concentration increased significantly after the downhill running and high-intensity trials, while plasma IL-10 concentration increased significantly only after the high-intensity trial. IL-4 and leukotriene B(4) did not increase significantly after exercise. Plasma IL-1ra and IL-10 concentrations were significantly higher (P<0.05) after the high-intensity trial than after both the moderate-intensity and downhill running trials. Therefore, following exercise up to 1 h duration, exercise intensity appears to have a greater effect on anti-inflammatory cytokine production than exercise-induced muscle damage.

Neutrophil activation remains unchanged after downhill running in well-trained runners, despite increases in plasma markers of muscle damage.

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Intense exercise stimulates the systemic release of a variety of factors that alter neutrophil surface receptor expression and functional activity. These alterations may influence resistance to infection after intense exercise. The aim of this study was to examine the influence of exercise intensity on neutrophil receptor expression, degranulation (measured by plasma and intracellular myeloperoxidase concentrations), and respiratory burst activity. Ten well-trained male runners ran on a treadmill for 60 min at 60% [moderate-intensity exercise (MI)] and 85% maximal oxygen consumption [high-intensity exercise (HI)]. Blood was drawn immediately before and after exercise and at 1 h postexercise. Immediately after HI, the expression of the neutrophil receptor CD16 was significantly below preexercise values (P < 0.01), whereas MI significantly reduced CD35 expression below preexercise values (P < 0.05). One hour after exercise at both intensities, there was a significant decline in CD11b expression (P < 0.05) and a further decrease in CD16 expression compared with preexercise values (P < 0.01). CD16 expression was lower 1 h after HI than 1 h after MI (P < 0.01). Immediately after HI, intracellular myeloperoxidase concentration was less than preexercise values (P < 0.01), whereas plasma myeloperoxidase concentration was greater (P < 0.01), indicating that HI stimulated neutrophil degranulation. Plasma myeloperoxidase concentration was higher immediately after HI than after MI (P < 0.01). Neutrophil respiratory burst activity increased after HI (P < 0.01). In summary, both MI and HI reduced neutrophil surface receptor expression. Although CD16 expression was reduced to a greater extent after HI, this reduction did not impair neutrophil degranulation and respiratory burst activity.

Australian and New Zealand Clinical Trials Registry (ACTRN12612001178831).

ACTRN12607000060448.

The aim of the present study was to determine the effects of a 4-week exercise training intervention on blood glucose, insulin sensitivity, BMI (body mass index) and cardiorespiratory fitness in patients with Type 2 diabetes, and to identify and establish criteria for patients who are more likely to improve their blood glucose from short-term exercise training. A randomized, controlled trial of exercise training, comprising two supervised and one non-supervised sessions of individualized cardiorespiratory and resistance exercise per week, was performed in 132 healthy patients with Type 2 diabetes (exercise training group, n=68), with the aim of accumulating a minimum of 150 min of moderate-intensity exercise for 4 weeks. BMI, waist circumference, blood pressure, blood lipid profile, blood glucose, insulin, insulin sensitivity [calculated by HOMA(IR) (homoeostasis model assessment of insulin resistance) and QUICKI (quantitative insulin check index)], beta-cell function (calculated by HOMA(beta-Cell)), HbA(1c) (glycated haemoglobin) and VO(2max) (maximal oxygen consumption) were measured at baseline and at 4 weeks. The exercise training group had significant improvements in VO(2max), BMI and triacylglycerols (triglycerides). There were no significant changes in blood glucose, HOMA(IR), QUICKI or HOMA(beta-Cell). Decreases in blood glucose were significantly predicted by baseline blood glucose and HbA(1c), with these variables accounting for 15.9% of the change in blood glucose (P<0.001). ROC (receiver operator characteristic) curve analysis revealed that patients with a blood glucose >8.85 mmol/l (sensitivity=73%, specificity=78%) and HbA(1c) >7.15% (sensitivity=79%, specificity=60%) were more likely to achieve a clinically significant decrease in blood glucose. In conclusion, in apparently healthy patients with Type 2 diabetes, a 4-week exercise intervention improved cardiorespiratory fitness, BMI and triacylglycerols. Elevated blood glucose and HbA(1c) predicted improvements in blood glucose.