Immune and hormonal changes following intense military training

Area of Science:

• Exercise physiology
• Immunology
• Endocrinology

Background:

• Military training programs often involve strenuous physical activity and sleep deprivation.
• These conditions can induce significant physiological stress on soldiers.
• Understanding the impact on immune and hormonal systems is crucial for soldier health and performance.

Purpose of the Study:

• To investigate the effects of a 5-day military course, following 3 weeks of combat training, on the immune and hormonal systems of male soldiers.
• To assess changes in specific immune markers and hormones in response to prolonged exercise and sleep deprivation.

Main Methods:

• Saliva and plasma samples were collected from 26 male soldiers before and after the military course.
• Assays were performed for secretory immunoglobulin A (sIgA), interleukin-6 (IL-6), dehydroepiandrosterone sulfate (DHEA-S), prolactin, catecholamines, glucocorticoids, and testosterone.

Main Results:

• Secretory immunoglobulin A levels decreased, indicating reduced mucosal immunity.
• Circulating interleukin-6 levels increased, suggesting sympathoadrenergic stimulation.
• Dehydroepiandrosterone sulfate, prolactin, and testosterone levels significantly declined.

Conclusions:

• Prolonged military training induces immune impairment, characterized by decreased mucosal immunity and elevated IL-6.
• Chronic stress during training negatively impacts immunomodulatory hormones like DHEA-S and prolactin.
• Reduced testosterone levels reflect a general decrease in steroid synthesis due to physical and psychological strain.