Whistling lungs after hard VO2max efforts

Hi everyone,

Today I did 5 hills in the 5 min to 8 min range as hard as I could. My power meter is being repaired at the moment but I gave it all and set several PR’s.

The first hill had a really hard 400 meter section at 17% gradient. At the top I was feeling as if my lungs were about to burst and my mouth had a blood taste. It took me a bit to recover but I did and did good times up the rest of the hills.

At the end of the ride I have had for 30 minutes whistling/wheezing lungs.

This is the first time ever this happens to me. Has anyone ever felt the same?

I don’t think its serious asthma because it is already gone but does anyone have any insight on how to avoid this or why it happens.

Thanks a lot!

I’m not going to comment on the blood taste but that sounds bad.

Purely speculation but my friend and I have chalked it up to being a tired diaphragm. Early in the season when I started going really long, coming home I always felt short of breath like I needed to cough. Lots of hours breathing harder than normal.

The other thing for me during vo2 work is it’s always going to irritate my throat lungs. Most sessions I’ll have a sore throat and cough afterwords

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Blood (iron) taste after really hard effort is something normal https://sciencenorway.no/exercise-forskningno-norway/why-does-your-mouth-taste-like-blood-during-intense-workouts/1435491#:~:text=Pressure%20on%20small%20arteries,in%20the%20lungs%2C%20called%20alveoli.
And it is rather nothig to worry about.


Thanks for the link quite clarifying, any experience with the whistling /wheezing lungs? Is what I was more concerned about

Maybe exercise induced asthma.

Exercised induced bronchospasm or bronchoconstriction I believe can present as both wheezing - sounds from narrowing airway on exhale. Or stridor - similar sounds on inhale.

I’m not a doctor and not giving any medical advice, but if it happens consistently and disrupts the athlete’s comfort or performance, they can consider consulting a doctor. Ideally a sports med doc with experience treating endurance athletes.

I’ll point out that part of the reason so many athletes have some diagnosis of asthma is because we push our lungs and airways to the limit. But EIB/EIA isn’t necessarily a sign of doing damage to our lungs/airways or any other underlying issue.


Seems very familiar to me - check out my thread. I am scheduled for a check up at the pneumology centre on Monday but I suspect it is (as already mentioned) exercise induced bronchoconstriction combined with allergy as an additional trigger.

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Thanks for your replies.

It is probably a form of exercise induced asthma for what I read.

It had never happened before even if I ve been riding for a while.

I really had to dig deep not to fall on the 39x28 over a very steep hill maybe I pushed myself much more than what my fitness and I could handle.

Maybe just need a bit of what Froome used at the Giro :smirk:

I’ll often get “track hack” after doing a true max effort in the 3-8 minute range, but it goes away by the following day.

IMO unless its affecting your ability to train or you have issues the following day, I wouldn’t worry about it.

Whistling/wheezing, are symptoms that occur in asthmatics. I would suggest that you see MD, specializing in asthma.