Introduction: Data concerning gender differences in insulin sensitivity are conflicting indicating either similar, higher or lower sensitivity to hormone action in women in comparison with men. However, in most studies the participants were middle-aged or elderly, characterized by excess of body fat and unknown physical activity level.
Aim of the study: The present study aimed at the evaluation of the association between plasma insulin and glucose, maximal oxygen uptake, and body composition in young, lean women and men.
Material and methods: A total of 76 male students with body fat up to 20% and 75 female students with body fat not exceeding 30% participated in the study. Maximal oxygen uptake was measured during incremental bicycle ergometer test. Plasma glucose levels were assayed using the oxidase method and Randox commercial kits. Plasma insulin concentrations were determined using radioimmunoassay and BioSource kits.
Results: Both in men and women maximal oxygen uptake was significantly and inversely correlated with the percent of body fat (r=-0.234; p<0.05 and r=-0.340; p<0.003 in women and men, respectively). Neither in men nor in women were plasma glucose and insulin levels correlated with maximal oxygen uptake. Exclusively in males the tendency to higher plasma insulin with increasing body fat was noted (r=0,214; p<0.07). In female subjects plasma insulin levels were significantly and inversely related to lean body mass (r=-0.264; p<0.03).
Conclusions: In young, lean men increased body fat contributes to the elevation in circulating insulin. On the contrary, in young lean women low lean body mass adversely affects plasma insulin levels.