I'm a pilot and lately I've been finding myself exhausted while flying. Sometimes, it's hard for me to stay awake. What should I do to prevent this feeling of exhaustion?
Is it just when you fly? If so, then consider hypoxia. Get a low-cost pulse ox and check your oxygen saturation. Also consider carbon monoxide issue. If this is not just related to flying, then see a physician an screen for other issues such as low thyroid, sleep apnea, cardiac, etc.