Fasting involves abstaining from food and water for periods as long as 12 hours. People with long standing medical problems such as diabetes, high blood pressure, recent surgical operations face the dilemma of a decision between faith and health. This situation also applies to the elderly.
My advice to people with medical conditions who are considering fasting is to discuss with their doctors before embarking on fasting. I am certain that faith organisations have exceptions to fasting. Your health is important and God is magnanimous. Stay healthy during the Ramadan.