Introduction. There is ample evidence that using carbohydrates during physical exercise contributes to increasing the duration of the physical load being experIenced. Still research devoted to the study of using carbohydrate solutions of different concentrations and in different quantities is of great interest. No definite results as to the time of assimilation of carbohydrates in respect to the starting point of the physical load undertaken are available either. Carbohydrates are the main source of energy during intensive exercise. The body of the athlete requires a greater amount of carbohydrates since they present in themselves the most efficient source of energy that prolongs muscle function by providing possibilities for the energy to be generated both aerobically and anaerobically. The topicality of the present study lies in the fact that it is aimed at establishing the effect of different solutions on the working capacity of athletes. The hypotesis of the research is: the assimilation of extra glucose 20 min after the start of running helps to prolong the duration of running. The aim of the research done was to establish the effect of using glucose during running on the duration of running possible. Subjects and methods. The subjects were seven long – distance runners (age 23.0 ± 1.9 years, height 1.82 ± 2.7 m, weight 77.0 ± 7.85 kg and body mass index 23.79 ± 2.06 kg/m2). Information as to health condition of the subjects, their physical activity and nutrition was... [to full text]