The Effects of Ramadan Fasting on Maximum Oxygen Uptake and Maximum Performance

The purpose of this study was to test maximal aerobic capacity and maximal performance during Ramadan fasting. Six volunteer subjects participated in the experiment. Venous blood samples were drawn, three-day dietary records were obtained, and body composition was measured before Rama{ian and during both the first and last weeks of Rama<;/an. Venous blood sarpples were analyzed for sodium, chloride, and protein. Treadmill measurements of maximum oxygen uptake (V02 max), ventilation, and respiration rate were recorded during the mornings and afternoons pre-Ramadiin, during the first week of Ramadah, and during the last week of Ramadan. First week Ramar!izn tests sho~ed a decrease in V02 max with a return to the pre-fasting levels in the last week. Ventilation and heart rate did not change, but respiration rate significantly decreased in the afternoon tests. Sodium, chloride, and protein increased during the first week and returned to the pre-fasting levels during the last week of Rama<;ian. Body weight significantly decreased throughout the experiments. While percent fat decreased during the last week, lean weight did not change. This study indicates a state of dehydration occurred during the first week of Ramadiin which was responsible for the decrease in body weight and may have contributed to the decrease in V02 max. Rehydration took place by the last week~! fasting with V02 max returning to pre-Rama<jiin levels.