The influence of an arduous military training program on immune function and upper respiratory tract infection incidence

Mil Med. 2006 Aug;171(8):703-9. doi: 10.7205/milmed.171.8.703.


The effects of the first 19 weeks of U.K. Parachute Regiment (PARA) training on upper respiratory tract infection (URTI) incidence and immune function (circulating leukocyte counts, lymphocyte subsets, lipopolysaccharide-stimulated neutrophil degranulation, and salivary immunoglobulin A concentrations) were investigated for 14 PARA recruits and 12 control subjects. No significant differences were reported between groups for the number or duration of URTIs, lymphocyte subsets, or salivary immunoglobulin A concentrations during training. URTI incidence was greater in the PARA group at weeks 2 and 3 (p < 0.05), coinciding with a decrease in circulating leukocyte and lymphocyte counts (p < 0.05). Neutrophil degranulation was similar in the PARA and control groups at weeks 0 and 19. Decreases in saliva flow rate occurred in the PARA group at week 15 and weeks 18 to 20 (p < 0.05). These results show a limited effect of PARA training on URTI incidence and immune function. The progressive decrease in saliva flow rate during PARA training may indicate an ensuing state of hypohydration.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aviation / education
  • Energy Metabolism / physiology
  • Exercise / physiology*
  • Humans
  • Immune System / physiology*
  • Immunoglobulin A, Secretory / analysis
  • Incidence
  • Leukocytes / physiology
  • Lipopolysaccharides / analysis
  • Military Personnel / education*
  • Respiratory Tract Infections / epidemiology*
  • Respiratory Tract Infections / immunology
  • Saliva / immunology
  • Teaching Materials
  • United Kingdom / epidemiology


  • Immunoglobulin A, Secretory
  • Lipopolysaccharides