Dr. Google

I did some research on the swollen hands after exercise thing. Turns
out to be quite common.

It is most common with runners, because of the high intensity cardiac
workout you get with running.

I wasn't running, but it was a more intense level of cardiac workout
than I usually do. And my body responded with a "what the heck are
you doing?" response.

Now what the actual cause for this happening, is a debated issue.
Some people believe it is from an electrolyte imbalance. Either too
little or too much salt. In my case I would say too little. I hardly
ever use salt and when I do, it is "No Salt" brand salt substitute.
The other school of thought is that the increased cardiac output
causes a centrifugal force kind of effect, where the blood pools at
the "outside" edges of your body - hands and feet.

So there you go. Sadly, I am NOT allergic to exercise.