Effect of 8 days of water-only fasting and vigorous exercise on anthropometric parameters, lipid profile and HOMA-IR in middle-aged men

Study aim: The aim of the present study was to determine the effect of 8 days of water-only fasting and physical exercise on somatic variables, lipid profile, insulin resistance and cardiovascular function in middle-aged men.Material and methods: Body weight, body composition, lipid profile, serum concentrations of insulin, glucose, beta-hydroxybutyrate (beta-HB), heart rate (HR), blood pressure and the homeostasis model assessment of insulin resistance (HOMA-IR) were determined in 16 apparently healthy men at rest and after aerobic exercise. This test procedure was also repeated after 8 days of water-only fasting.Results: Fasting intervention resulted in a reduction in body weight and fat mass (p < 0.001). The simultaneous effect of fasting and exercise resulted in significant changes in lipid profile, carbohydrate metabolism and cardiovascular function. Post hoc analyses showed that the reductions in insulin and glucose concentrations as well as the HOMA-IR index were caused by the fasting, and changes in the lipid profile and cardiovascular function were caused by the exercise test.Conclusion: The combined use of fasting and physical effort resulted in an optimal effect on health indicators of the surveyed men.