Immune responses, upper respiratory illness symptoms, and load changes in young athletes during the preparatory period of the training periodization

Abstract

Diego Trevisan Brunelli,1 João Paulo Borin,1 Ariel Rodrigues,1 Valéria Bonganha,1 Jonato Prestes,2 Paulo César Montagner,1 Cláudia Regina Cavaglieri11Faculty of Physical Education, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil; 2Graduate Program of Physical Education and Health, Catholic University of Brasilia, Brasilia, Distrito Federal, BrazilObjective: The aim of this study was to investigate the immunological responses and the association between variation in exercise load and self-reported occurrence of upper respiratory illness (URI) symptoms in young basketball athletes.Materials and methods: The sample was composed of twelve young male athletes aged 12.7 ± 0.6 years, with a height of 170 ± 10 cm, body mass of 57.6 ± 12.6 kg, and fat-free mass of 18.7 ± 5.9%. Daily training and occurrences of URI symptoms were recorded. Blood samples were collected at baseline (M1) and after 8 weeks (M2) of the preparatory period of periodization training to measure total and differential leukocyte counts, serum interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α).Results: There was a significant decrease in monocytes at M2 compared to M1 (P = 0.004). There were no significant alterations in total leukocytes (P = 0.07), neutrophils (P = 0.07), or lymphocytes (P = 0.09). No significant changes in plasma concentrations of TNF-α (P = 0.30) or IL-6 (P = 0.90) were found. The weekly load from week 6 was higher when compared with weeks 1, 2, 4, and 8 (P < 0.05), and week 8 was the lowest when compared with week 5 (P < 0.05). Self-reported URI incidences were highest at weeks 1 and 2.Conclusion: Variations in weekly training load during the preparatory period were not correlated with changes in self-reported occurrence of URI incidences, suggesting that young athletes may have an attenuated response to exercise-induced perturbations to the immune system.Keywords: immune system, upper respiratory illness, young athletes, cytokines