Relations between vitamin D status, muscle tone and body composition in soldiers: association with long-term mission

Abstract

Vitamin D level is known to play an important role in the regulation of different human functions, including the functions of the cardio-vascular and musculoskeletal systems. The aim of the study was to find relations between vitamin D level, skeletal muscles tone and body composition in conditions of prolonged physical load.

Sixty-five well-trained male soldiers from the Estonian ESTCOY-8 infantry company were examined before and after a six-month military mission to assess the soldiers’ vitamin D level, skeletal muscles tone and body composition.

The results of the study showed that, during the long-term military mission, muscle tone of lower extremities decreased in conditions where vitamin D status was significantly increased (from average 40 to 104 nmol/L; p<0.001). We also found that the upper and middle part m. trapezius tone increased significantly during long-term strenuous military mission.

Our study showed that the long-time military mission influenced the skeletal muscles functional state. Decrease in muscle tone of lower extremities was related to increase in serum vitamin 25(OH)D level (in average by 64nmol/L). At the same time muscle tone of m. trapezius increased in our group of subjects, and this increase was linked to WHR.