BLOOD BIOCHEMICAL CHANGES AFTER DRAMATIC INCREASE IN RUNNING TRAINING VOLUME: EXPLORATORY STUDY IN 3 ELITE SOLDIERS

Ultra-Endurance running training is a powerful stressor for all biological systems and depends mainly on its volume and intensity. Although the high physical demands, soldiers are an unstudied group and information on exercise indicators are essential. This study aimed to observe the changes in serum biochemical indicators in previously endurance trained elite soldiers after a 17-week training program with a dramatic increase in running volume. Three subjects (#1: 26 years, 169,5cm; #2: 27 years, 167,9cm; #3: 27 years, 180,7cm) running daily between 10-12 km/day, increased their running volume to prepare the participation in a 100-km ultramarathon race. For 17 weeks the training program included 10-12 sessions per week, corresponding to 200-260 km. Average daily running volume was 35.8±6.2 km. Blood samples were taken for analysis of urea, creatinine, glucose, cholesterol and triglycerides, AST, ALT, CK, aldolase, Na, chloride, P, Ca, K, Fe, Mg and cortisol. Despite a marked drop in iron and a rise in phosphorus, the overall mineral status remained within laboratory reference values. ALT, AST, Aldolase showed slight changes while a marked increase was found in CK. Creatinine decreased and urea maintained the high starting values. Changes of glucose, cholesterol and triglycerides had no clinical significance. After the 17-week the cortisol increased to outside of the reference values in two participants. This study shows that a dramatic increase in running training volume experienced by previous trained runners is mainly reflected in basal blood chemistry through the reduction of iron and creatinine and increase of cortisol.