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.


METHODS
An observational study for one soccer season (one year).


METHODS
Professional soccer players.


METHODS
Thirteen professional soccer players (age: 26.3 +/- 3.7 years).


METHODS
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.
Rebelo
A N
AN
Faculty of Sport Sciences, University of Porto, Portugal.
Candeias
J R
JR
Fraga
M M
MM
Duarte
J A
JA
Soares
J M
JM
Magalhães
C
C
Torrinha
J A
JA
D000328:Adult; D016516:CD4-CD8 Ratio; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D005500:Follow-Up Studies; D006801:Humans; D007111:Immunity, Cellular / Q000276:immunology*; D007694:Killer Cells, Natural / Q000276:immunology; D007958:Leukocyte Count; D007962:Leukocytes / Q000276:immunology; D018655:Lymphocyte Count; D016131:Lymphocyte Subsets / Q000276:immunology; D009504:Neutrophils / Q000276:immunology; D012916:Soccer / Q000193:education / Q000502:physiology*; D013601:T-Lymphocytes / Q000276:immunology