Hello, Chronic fatigue and drowsiness my be indicative of poor general health condition, stressful lifestyle (emotional or physical), some major vitamin/mineral deficiency, inadequate quality sleep, over exertion, never taking a break from work, etc. Other medical conditions that cause such symptoms are chronic fatigue syndrome, anemia, anxiety disorders, live, kidney issue, etc. You are a swimmer and swim three times a week for two hours and feel exhausted and drowsy the rest of the time; any type of exhaustion after swimming needs to be investigated to rule out developing CAD. You are suggested to get a complete medical check up done. Get all required blood workouts, urinalysis and imaging tests done to detect the factor causing you discomfort. You will be treated accordingly. In the meantime stay away from addictions if any. Take home made balanced food rich in vitamins and minerals. Avoid stress and anxiety. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Nupur K., General & Family Physician