Why does your saliva start to taste like blood if you ride your bike up a hill or run fast for a while?
Edit: Thanks for the Awards and the nice Comments.
Also blew up bigger than I thought!
In: Biology
It may sound weird, but I experienced it once and got the explanation that it’s because your lungs get rid of the slimy protection film on your bronchia to get more oxygen into your blood. This slim on the other hand can have tiny red platelets which give you that weird blood taste and sometimes coughing afterwards as well.
There are many theories but no one knows why, some of the explanations here are a likely culprit but overall there likely isn’t a single root cause for everyone.
Not everyone experiences it, and it seems not to be directly correlated to your level of fitness either.
Also not everyone experiences it due to stress levels alone for example I only experience it when running in cold weather, the likely explanation for me is that colder dryer weather might cause more raptures in blood vessels in the throat, nose and tear ducts which means more blood cells get funneled into my mouth as I exhale or through the mucus.
P.S. some people mentioned metallic taste before throwing up, the metallic taste before throwing up isn’t related to this, that happens every time you are about to throw up and it’s due to a reflex trigger that increases saliva production to provide lubrication to reduce choking and to protect your throat and mouth from your gastric acid and any thing you might have swallowed that didn’t or couldn’t be digested (historically and even today some animals including mammals throw up bones that they swallow and also may throw up other particulates like sand or small rocks that they swallow intentionally or unintentionally during feeding, so the vomit reflex is likely shared across all of mammals just like the mammalian diving reflex).
You could quite likely cause that sensation at will by thinking about throwing up.
**Eli5 version**: Our blood contains iron. When you do strenuous exercise the pipes supplying blood to the balloons in your chest start leaking some of that iron-containing part of blood. When the balloons deflate, that’s when you exhale, some of that iron reaches your mouth from those balloons and your taste-thingamagigs tell you that you have iron in your mouth.
Oh god I figured it was just because I’m a weakling. The two people I’ve ever mentioned it to said it never happened to them.
This is weird. I work out all the time and yace never noticed any change to the taste of saliva. Interesting, though.
I’ve never had that happen that I know of, but I will say that I have really bad teeth and have definitely spent some time tasting blood. Ok cool. Bye.
The taste that can be present in your mouth might be similar to the one of blood, or just metallic. Happens usually when performing hard exercises with not a lot of previous training or preparation, exercising at high altitudes or in cold and dry air.The taste is a byproduct of the fact that the heart is working way harder than usual causing pulmonary edema (buildup of fluids in the lungs), and with this there’s an increase in pressure which causes a leakage of erythrocytes (Red blood cells) into your lungs. Haemoglobin (the molecule present in RBCs that allows transport of oxygen) are bound to iron ions and when RBCs have entered the lungs, haemoglobin can escape into the bronchi, then the trachea, larynx and finally reaches the mouth, where the taste receptors on the tongue sense iron and send a signal to your brain causing this metallic/bloody taste in your mouth.
Edit: Might be a little too specific and complicated for ELI5 but I’ll still leave it here
Basically why you exert yourself you blood cells “pop”.
Working out hard means the red blood cells are working hard too, the harder they work the more *heme* they release which is what gives that taste of metal. They can also leak into your lungs which can persist the taste as you breathe heavier during a workout.
It will go away after the body adapts though!
When you complete a quick, strenuous exercise, some excess hemoglobin is released from your blood cells into the lungs, which is then moved to your mouth during an exhale. Since hemoglobin is also made up of iron, that is what your receptors detect- hence the blood taste.
Since there are 397 comments here, I assume no one will ever see this.
The top answer is wrong. It has to do with the decreased blood pH from retained CO2.
The effect is a known symptom of patients with metabolic acidosis for instance. It is also a warning sign when free-diving. Obviously there is nothing moving into your mouth when you are underwater.
You can taste it yourself if you hold your breath for 90 seconds.
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