The physiological effect of fasting includes lower of blood sugar, lowering of cholesterol and lowering of the systolic blood pressure. In fact, Ramadan fasting would be an ideal recommendation for treatment of mild to moderate, stable, non-insulin diabetes, obesity and essential hypertension. On the other hand, patients who are suffering from severe diseases, whether diabetes or coronary artery disease, kidney stones, etc., are exempt from fasting and should not try to fast. There are psychological effects of fasting as well. There is a peace and tranquility for those who fast during the month of Ramadan.
Personal hostility is at a minimum, and the crime rate decreases.
This psychological improvement could be related to better stabilization of blood glucose during fasting as hypoglycemia after eating, aggravates behavior changes. There is a beneficial effect of extra prayer at night. There are 10 extra calories output for each rikat of the prayer. Again, we do not do prayers for exercise, but a mild movement of the joints with extra calorie utilization is a better form of exercise. Similarly, recitation of the Quran not only produces a tranquility of heart and mind, but improves the memory.