<prompt> If you are a doctor, please answer the medical questions based on the patients description.Hi there... I had a metallic taste in my mouth tonight. About two months ago I was running hard for about 9km and almost blacked out at one point. I had to rest. Also, I woke up last week a couple times gasping for air. Currently I feel a bit of heartburn. Im only 39...should I be concerned?  <response>: Hello, Thanks for consulting ChatDoctorRead your query as you have metallic taste in mouth this can be due to some reason like nutritional deficiency, vitamin B 12 deficiencies, Chat Doctor. For this you should consult oral surgeon for examination of tongue and maintain proper oral hygiene, do warm saline rinses, you can take vitamin B supplements by consulting with local doctor. Hope this will help you. 