Background: Excessive workload may have transient detrimental effects on left ventricular function and arterial stiffness. Furthermore, heavy endurance physical exercise has been shown to induce short-term systemic inflammation response. Recently, vitamin D has attracted increased attention owing to its potential anti-inflammatory effects. The aim of this study was to investigate the impact of a 6-month military mission on arterial stiffness, inflammation, and vitamin D level.

Methods: Sixty-five soldiers (age 26±4 years) deployed to a peacekeeping mission in Afghanistan for 6 months were examined before and after the mission. We assessed arterial stiffness by carotid-femoral pulse wave velocity and pulse wave analysis using the Sphygmocor device. A set of inflammation-related markers was assessed in the blood using biochips. Serum 25-hydroxyvitamin D level was measured using a radioimmune assay.

Results: Arterial stiffness and brachial and central blood pressure did not differ significantly before and after the mission. Vitamin D level increased by 2.6 times (40±15 vs 104±24 (nmol/L), p<0.001). Significant increases were observed in high-sensitivity C-reactive protein (0.68±0.7 vs 1.47±3.55 (mg/L), p=0.03), leukocyte count 5.4±1.1 vs 6.3±1 (x10⁹/L), p<0.001), as well as in various pro-inflammatory cytokines, including IL-1α (0.13±0.18 vs 0.2±0.23 (pg/mL), p<0.001), IFN-γ (2.6±2.4 vs 5.3±3.4 (pg/mL), p<0.001), and MCP-1 (151±61 vs 229±95 (pg/mL), p<0.001).

Conclusion: Arterial stiffness was not altered by arduous conditions during the deployment. However, there were significant changes in the spectrum of inflammation markers and vitamin D levels. We speculate that elevated vitamin D levels may have ameliorated the possible inflammation-induced changes in arterial stiffness.