To investigate the acute changes in leukocyte number and cortisol after a single bout of soccer training.
Ten elite female national-team soccer players and 8 nonathletes participated in the study. The duration of the exercise was 2 h, and it was performed at an intensity of 75% of maximal heart rate (HRmax). Blood samples were taken before, immediately after, and 4 h after a soccer training session to determine total white blood cells; the subsets of neutrophils, lymphocytes, monocytes, eosinophils, and basophils; and cortisol. At the same time, blood samples were obtained from nonathletes who refrained from exercise.
Data analysis indicated a significant increase in total white blood cells in the athletes postexercise (P < .001). The leukocytosis was still evident after 4 h of recovery (78% higher than the preexercise values), and there was a significant difference between athletes and nonathletes (P < .001). This leukocytosis was primarily caused by neutrophilia—there were no significant differences in lymphocytes after the end of exercise or between the 2 groups (P > 0.05). In addition, there was a statistically significant difference in cortisol concentration between athletes and nonathletes after the exercise (P < .001).
These findings revealed that the single bout of soccer training at an intensity of 75% of HRmax induced leukocytosis without affecting the lymphocyte count in elite female athletes and probably the effectiveness of cellular components of adaptive immunity. Coaches should provide adequate time (>4 h) until the next exercise session.
Avloniti, Douda, and Tokmakidis are with the Dept of Physical Education and Sport Science, Democritus University of Thrace, Komotini, 69100 Greece. Kortsaris, Papadopoulou, and Spanoudakis are with the School of Medicine, Democritus University of Thrace, Alexandroupoli, 68100 Greece.