Background: On the basis of available reports it can be stated that physical stress causes changes in distribution and activity of many components of the immune system. It is believed that psychophysical stress in soldiers can influence their immune system depressively and in consequence increase the risk of upper respiratory tract infections. Therefore, it was decided to conduct studies aimed at the estimation of the influence of military training on the some parameters of cellular immune response.
Material/Methods: The study group consisted of 40 draft aged from 18 to 23 years. The research was conducted in the first 8 weeks of service, in the period of the most intense draft stress adaptation. The participants were divide into 2 groups, A and B respectively, 20 soldiers each. Group A derived from an assault unit. Their training induced strenuous physical stress. Group B derived from a support unit. Their training required less physical effort then one of group A. Performed examinations involved: lymphocyte percentage count, lymphocyte proliferative response to mitogen, CD69 antigen expression on T lymphocyte surface, delayed hypersensitivity reaction with CMI Multitest. All assessments were done twice at 8 weeks interval.
Results: After 8 weeks of training in the A group a statistically significant increase in the percentage of lymphocytes revealing antigens of the II Class Main Histocompatibility Complex (MHC) was found. In addition, in this group a statistically significant decrease in the value of lymphocyte stimulation index, a statistically significant increase in the percentage of cells revealing CD69 antigen expression after PHA stimulation were observed. During investigated period in the B group following statistically significant changes were found: an increase in the percentage of CD3+ and CD4+ cells, a decrease in the percentage of CD16+CD56+ and an increase in the CD4+ to CD8+ ratio.
Conclusions: The obtained results show that military service conditions influence some parameters of the cellular immune response but do not result in the clinically significant suppression of the immune system.

Keywords: psychical stress, physical workload, cellular immune response