Lots of stuff causes dizziness after/during exercise. But if you Google "dizziness after exercise" you'll get 10,000 articles and lame blogs that are basically just copies of one another that all essentially make the same vague blanket statement:

In rare cases, heart conditions can cause dizziness after/during exercise.

But, LOL, not a single one of these articles/lame blogs actually deep dives into what specific heart conditions they are referring to.

So I ask: What specific heart conditions would cause dizziness after/during exercise, and why do they make one dizzy?

  • 3
    What exactly are we talking about here? Actually dizziness like hard to stand up or just runner's high where you feel kinda euphoric, light headed, relaxed, flexible and air headed.
    – maplemale
    Nov 6, 2015 at 19:51
  • "Dizziness" as in light headedness almost to the point of fainting. Not a vertigo "the whole world is spinning" senation, and not a runner's high.
    – smeeb
    Nov 6, 2015 at 20:02
  • 1
    Interesting. Most of the conditions that I am aware of (as a lay person) would also cause dizziness during exercise.
    – JohnP
    Nov 6, 2015 at 20:07
  • Hi @JohnP (+1) - I'll relax the constraint for strictly "after" exercise (please see my edits). The reason for this is that, in my case, I definitely get hints of dizziness during exercise, but it typically does not set in until after my cooldown period.
    – smeeb
    Nov 6, 2015 at 20:19
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    In addition to heart conditions there are some non-cardiac conditions and many meds that can do the same. Are you including those in your question or strictly heart conditions?
    – Carey Gregory
    Nov 7, 2015 at 0:52

1 Answer 1


Dizziness or giddiness during exercise is classically caused by obstruction to the outflow of the heart i.e. aortic stenosis (see MedlinePlus). This condition is most commonly seen in either young persons due to bicuspid aortic valve or in elderly with sclerotic aortic valves. In developing countries, it may occur due to rheumatic heart disease also.

When a normal person exercises, extra blood flow is needed in the muscles. Hence, heart starts pumping more blood to keep up with this increased demand of the body. However, in persons with aortic stenosis, orifice of the outlet of the heart is small and fixed. Hence, blood flow (cardiac output) cannot increase when person exercises. Due to blood vessel dilatation in muscles, blood goes preferentially to muscles and flow to the brain gets reduced. Hence giddiness or dizziness occurs. It can progress to syncope, i.e. transient unconsciousness and fall.

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