Monitoring physiological biomarkers in soccer

Saliva and blood sampling has been increasingly used as a diagnostic tool for the assessment of physiological biomarkers in elite sport. In elite level soccer, considerable physiological and psychological stress can be experienced throughout the season. The consequence of having periods where players are in a sub optimal physiological state could lead to a reduction in performance, impaired immunity and increased risk of infection. Monitoring the variations and relationships of salivary and blood biomarkers in response to exercise and specifically elite soccer can provide detailed information on the physiological status of the players. This review will focus on the responses of salivary immunoglobin A (sIgA), cortisol, urea, and creatine kinase (CK) to exercise and elite soccer