Proceedings of The Physiological Society
University of Central Lancashire (2002) J Physiol 543P, S242
Effect of moderate exercise on the functional capacity of neutrophils of sedentary individuals
J.M. Marchena, A.B. Rodr
Department of Physiology, Faculty of Science, University of Extremadura, Avda Elvas s/n, 06071 Badajoz, Spain
- Figure 1. Phagocytosis index (A) and candidicide index (B) for neutrophils from sedentary individuals. The bar represents the mean and the standard deviation (S.D.) of 6 determinations performed in duplicate. +P < 0.05 relative to the values obtained in the basal state (Student's unpaired t test). *P < 0.05 relative to the values obtained immediately following the exercise (Student's unpaired t test).
It has been suggested that moderate exercise is good for the immune system, although the effect will depend on the intensity and duration of the exercise (Nieman & Pedersen, 1999). The goal of the present work was to evaluate the effect of a single session of moderate exercise (60 % VO2,max) on the functional of capacity of neutrophils from sedentary individuals. Under the approval of the Ethical Committee of the University of Extremadura, six sedentary men were subjected to a 45 min session on an ergometric bicycle. The functional status of their neutrophils was evaluated before the trial, at the end of the trial, and after a further 24 h had passed. To this end, neutrophils were isolated from blood samples in a density gradient (Ficoll/Histopaque). After incubation for 60 min with Candida albicans, their functional capacity was evaluated by the phagocytosis index (number of candidae ingested by 100 neutrophils), phagocytosis percentage (percentage of neutrophils which have phagocytosed at least one candida) and phagocytic efficiency (mean number of candidae phagocytosed by each neutrophil that has phagocytosed at least one candida), and their microbicidal capacity by the candidicide index (number of dead candidae) and the candidicide percentage (percentage of dead candidae per 100 neutrophils).
The results showed a significant rise (P < 0.05) in the phagocytosis index after exercise (153.33 ± 17.95) and 24 h later (132.00 ± 15.34) relative to the basal levels (111.67 ± 6.50). No significant differences were observed, however, in the phagocytosis percentage, although there was a significant difference (P < 0.05) for the phagocytic efficiency between the basal value (1.46 ± 0.11) and after the performance of the exercise (1.90 ± 0.35). With regard to the microbicidal capacity, the candidicide index rose significantly (P < 0.05) following the exercise (112.67 ± 13.25) and after 24 h (100.00 ± 11.59) relative to the basal value (78.00 ± 10.39). No significant differences were observed, however, in the candidicide percentage (Fig. 1).
A conclusion that can be drawn from the study is that, when a sedentary individual performs moderate (60 % VO2,max) exercise, there is a resulting protection of the host via activation of one of the groups of cells responsible for the non-specific immune response.
The authors thank Elena Circujano Vadillo for technical assintance. This research was supported in part by Grant IPR98AO18 from the Junta de Extremadura-Fondo Social Europeo.
All procedures accord with current national guidelines.
Where applicable, experiments conform with Society ethical requirements