The impact of soccer training on the immune system.

OBJECTIVE: The aim of this study was to evaluate whether the level of some immune markers changed in soccer players during pre-season and during playing-season. DESIGN: An observational study for one soccer season (one year). SETTING: Professional soccer players. PARTICIPANTS: Thirteen professional soccer players (age: 26.3 +/- 3.7 years). MEASURES: The effect of 11 months of soccer training sessions and matches on circulating leukocyte and lymphocyte subpopulations was investigated. Blood samples were taken before the season and also 6 weeks, 6 months and 11 months later. All samples were taken at 08:00 h. RESULTS: Total lymphocyte counts did not change in all samples. During the pre-season, however, the concentrations of some inflammatory lymphocyte subpopulations were changed: CD4CD45RA+ was elevated and CD57 and CD8CD57 showed a significant decrease (p < 0.05), At the competitive period, CD4 and CD8 were increased. At the end of the season there were significant changes in some immune cells: total leukocyte and neutrophil number and CD8+ cell concentration was increased compared to pre-season values and the CD4/CD8 ratio was decreased. CONCLUSIONS: The results suggest that athletes exposed to a long-term training periods can exhibit variations in some immune cells. The clinical significance of these variations requires more detailed investigation.

[Is autonomic control of the heart rate at rest altered by detraining? A study of heart rate variability in professional soccer players after the pretraining period and after the preparatory period for competitions]. / O controlo autonómico da frequência cardíaca em repouso e alterado pelo destreino? Estudo da variabilidade da frequência cardíaca em futebolistas profissionais após o defeso e após o período preparatorio das competições.

The aim of this study was to assess the influence of detraining and training on the autonomic control of heart rate (HR), using time and frequency (spectral analysis) domain components of heart rate variability. Sixteen professional football players (26.7 +/- 3.8 years; 74.9 +/- 4.1 kg; 177 +/- 6.3 cm) were analysed at the end of a 1 month holiday (detraining) and after a 6 week training period (training). HR was recorded over 15 minutes with Holter equipment. The athletes rested in a supine position, in a quiet place and all test were performed between 8 and 10 AM. The subjects were requested to refrain from meals or caffeine for 12 hours before testing. In spite of the high intensity of the training period, there was no significant change in results from detraining condition to training condition. These results can have two possible explanations: (i) the high level of cardiovascular capacity in the detraining trial originated by the recreative physical activity that the players underwent during their holidays, and/or (ii) the training period was not long enough to promote any relevant effect on the autonomic control of HR.