If I "push it" on the treadmill or during a race, for a sustained amount of time (as little as, say, 10 minutes), I will likely experience something that is a little hard to describe but I will attempt to do so. It is basically a metallic "taste", although it seems to be originating from my head, and it's more like a general sense of metal rather than a taste. If my brain had tastebuds, this would be what I'm experiencing. This may sound ridiculous to you or you may say "that's it!", I suppose your mileage may vary (pun intended).

I thought it might be blood, which would account for the metal sense, but I never see any blood.

I am taking no drugs and do not have any diagnosed medical conditions, and I'm 40 years old. I think this has been happening ever since I had the ability to run, so pretty much since tykehood.

Here is an interesting link but I'm still not satisfied. The mention of "taste phantoms" seems like a possible jumping-off point, though.


  • 4
    Not sure in your scenario, but as one possible clue metallic taste is often a sign of being in ketosis. If you'ved burned off any available blood sugar during your push, perhaps there's a common cause?
    – G__
    Jan 29, 2014 at 17:14
  • So... did you have a question, too ;) ?
    – user8119
    May 28, 2015 at 10:38
  • @LarissaGodzilla I suppose I'd kinda hoped the Physical Fitness site would be subject to a little less "format rigor" than stack overflow and maybe be a little more discussion-y. Jul 2, 2015 at 16:37
  • I had the same thing happen to me this morning during my workout, and from my research it could be ketosis (when your body runs out of carb energy and begins burning fats). I could not find out exactly why it smelt like/ tasted like metal; but you are right it seems to come from the head.
    – user23692
    Sep 26, 2016 at 12:30
  • Can you give us your typical diet? Might rule out ketosis.
    – John
    Sep 26, 2016 at 14:51

3 Answers 3


Barring any unknown medical issues, it's possible that you're simply exerting beyond your heart's ability to keep up, so to speak. The fact that you mention that this occurs when you push yourself. At rest, your heart pumps out as much blood as it pumps in. Blood from the body comes into the heart via the right side (atrium to ventricle) which is then pumped to the lungs for reoxygenation. That reoxygenated blood then goes back to the heart (the left side) to be sent to the rest of the body (and then that spent blood goes back to the heart via the right, etc.).

When the left side isn't efficiently able to keep up with the demands of your body, fluid starts collecting in minute traces in your lungs, sort of as a backlog. And since you're breathing, you're catching the scent and a small amount of the taste (which is tied to smell anyway) of the hemoglobins in your blood.

When you rest, your heart begins to catch back up to the body's slowly decreasing demand and the smell likely goes away at that point.

http://www.runnersgoal.com/why-do-i-have-a-metallic-taste-in-my-mouth-during-strenuous-exercise/ http://www.livestrong.com/article/322820-metallic-taste-in-the-mouth-during-exercise/

  • I think this is pretty solid, although I wonder if it's my lungs and not my heart. In any case, something in the cardiopulmonary chain is not doing it's job to my satisfaction and it feels a bit like I'm struggling to get sufficient oxygen. Can a person get asthma later in life? I guess I have my homework. Jul 2, 2015 at 16:40

This is a little late, but I'll bet you're smelling ammonia. It's very common when you exert yourself. See the following:



Hope it helps, Mike

  • Rather than posting some links, which may become invalid over time, you should explain your answer and use the links as reference.
    – rrirower
    Apr 22, 2017 at 17:05
  • I'm not a doctor, but this just really seems right. May 30, 2017 at 15:24
  • So did it go away? I got this for about a week and must have sweat out some bad stuff after not having worked out hard for a long time and then abruptly starting back full on!
    – Mike
    Aug 2, 2017 at 1:18
  • I haven't noticed this so much lately, but my gym routine is more weights-centric. I do some rigor on the stair machine and I do some "HIIT" on the treadmill (in quotes because I'm not sure the "H" is super accurate). Mar 12, 2020 at 16:31

You can start to think from most simple and common causes of metallic taste:

The Allexperts site you linked, mentions mouth dryness as one of the causes. 10 minutes into running you could have dry mouth from:

  • breathing through mouth (also, intense breathing through nose can cause dryness of the nasal mucosa possibly resulting in a "metallic smell.")
  • adrenaline release due to stress (running) resulting in a similar dry mouth as when you are anxious
  • mild dehydration (not that 10 minutes of running will dehydrate you, but being mildly dehydrated before you start running can add to mouth dryness during running)

Acid reflux can cause metallic (bitter, sour) taste (WebMD). You can have acid reflux without typical heartburn.

Any minor mouth (gum/teeth) or nose condition (with or without blood) can be associated with metallic taste.

About ketosis:

You do not go into ketosis in 10 minutes of running (if you are healthy and not on a ketogenic diet). If you had ketosis before starting running, you would also likely have metallic taste before running.

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