High intensity training and salivary immunoglobulin: a responses in professional top-level soccer players: effect of training intensity

This study aimed 1)- to test the hypothesis that salivary immunoglobulin A (s-IgA) would vary with training intensity sessions (low intensity [LI] vs. high intensity sessions [HI]) during a traditional training program divided in 4 training periods and 2)- to identify key variables (e.g. GPS data, RPE, training duration) which could affect s-IgA. Saliva samples of 10 elite professional soccer players were collected a)- before the investigation started to establish the baseline level, b)-before and after each 4 training sessions (LI vs. HI). Training intensity was monitored as internal (via heart rate responses and RPE) and external (via GPS) loads. HI sessions were associated with higher external load (GPS) and with higher RPE. Baseline and Pre-Training s-IgA did not differ between the 4 training sessions both for HI and LI. Post-Training s-IgA were not different (in absolute value and in percentage of change) between HI and LI sessions at the first three periods. However, at the fourth period, s-IgA concentration for HI session was significantly lower (p\u3c0.05) than the LI session. The percentage change between s-IgA post-training and s-IgA baseline concentrations differ significantly (p\u3c0.05) between HI and LI training sessions. Significant correlations between s-IgA and training intensity were also noted. HI soccer training sessions might cause a significant decrease in s-IgA values during the post-exercise window as compared with LI sessions. This study encourages coaches to monitor s-IgA in routine particularly during HI training periods to take precautions to avoid upper respiratory tract infection in highly trained soccer players