Background: So far, there have been a few and incoherent results about the effects of physical activities. Fasting in Ramadan has an effect on the level of osmolarity and the concentration of serum electrolytes both in active and inactive females.. Objectives: The aim of this study was to observe the changes of serum electrolytes and osmolarity levels according to regular exercise during fasting. Patients and Methods: Twenty two healthy females who were elected by convenience sampling method were divided into two groups: 1) fasting + exercise (FE; n = 11) and 2) fasting + non exercise (FNE; n = 15). The FE group participated in aerobic training for four sessions per week during the fasting. All measurements were done once before the first day, on the second week, on the fourth week and two weeks after fasting month and these measures were used to analyze test results. Results: The mean differences were as follows: significant weight loss, BMI, WHR, in two groups at the end of Ramadan (P < 0.05). The mean of weight, BMI, WHR, body fat, protein, mineral and total water showed no difference between groups (P > 0.05). Potassium, creatinine, urea and uric acid had been decreased significantly in both groups (P < 0.05). Variance between groups was significant only in variable urea (P < 0.05). Variations within group had been changed in FBS; sodium, phosphorus and osmolarity levels were not changed significantly. Conclusions: According to this result, regular exercise in case of fasting in Ramadan led to some changes in serum osmolarity index, electrolytes and water. Therefore, it is important for female athletes to consider applying a suitable nutritious diet and sufficient water consumption during Ramadan.

Keywords