A Single Bout Of Moderate Intensity Exercise Has Neither A Pro- Nor Anti-inflammatory Effect

Abstract

The long-term anti-inflammatory and anti-atherogenic effects of regular physical activity may be due to the transient responses elicited by each bout of exercise. PURPOSE: To determine whether a 30-min walk at a moderate intensity induces a pro- or anti- inflammatory response and alters lymphocyte adhesion. METHODS: Twelve inactive male volunteers (age 54 ± 4 y, body mass 87 ± 9 kg, VO2 max 34.4 ± 3.9 ml.kg-1.min-1) completed two main trials, one exercise (30 min at 50% VO2 max) and one rest (30 min quiet sitting), separated by at least seven days. A baseline venous blood sample was collected prior to exercise or rest and then immediately post-trial (0 h), 2 h, 24 h, 48 h, 72 h and 168 h after each trial. Mononuclear cells were isolated from the blood and lymphocyte adhesion to cultured endothelial cells (HMEC-1) stimulated with 0.1 ng.ml-1 tumor necrosis factor-α was assessed. Lymphocyte and monocyte Heme Oxygenase-1 (HO-1) protein expression was determined by flow cytometry. Serum Interleukin-6 (IL-6) and C-reactive protein (CRP) were measured by ELISA. Data were analysed using a two-way repeated measures ANOVA. RESULTS: The intensity of the exercise performed by the volunteers was 53 ± 2% VO2 max (equivalent to 5.2 ± 0.7 METs). Over the seven days following exercise there was no significant change in circulating neutrophils, lymphocytes, monocytes or serum IL-6 and CRP concentration. Similarly, lymphocyte adhesion to cultured endothelial cells and HO-1 expression in lymphocytes and monocytes was not affected by walking at any time point. CONCLUSION: These results suggest that the long-term anti-inflammatory and anti-atherogenic effects of regular moderate intensity physical activity are unlikely to be due to the profound effect of each exercise bout since a single bout of walking did not lead to a detectable change in systemic markers of inflammation (pro- and anti-inflammatory) or lymphocyte adherence to cultured endothelial cells. The anti-inflammatory and anti-atherogenic effect of regular physical activity is either the result of very subtle changes associated with each exercise bout or due to other changes that accumulate when exercise is performed over weeks and months. Supported by The British Heart Foundation.