Weakness and fatigue. About his health.

My father aged 60 years had undergone Coronary Artery Bypass Grafting (CABG) in 2021. He recovered well after the surgery and does not have any known history of diabetes or high blood pressure. However, for the past couple of months he has been experiencing occasional dizziness and sudden weakness. When we checked his blood pressure it was normal, but we still decided to take him to the hospital. He was kept under observation for 24 hours and all the reports came back normal. The doctor discharged him and suggested that the problem might be due to gastric issues. Recently, he has been getting tired easily, so we decided to check his blood sugar and lipid levels. His fasting blood sugar was 166 and triglycerides were 266. After one month, we repeated the tests and his fasting sugar was 151 and triglycerides were 208. At present, he sometimes feels weak and is not able to walk fAt present, he sometimes feels weak and is not able to walk fast as before. We are concerned about his health.