It comes on slowly - usually at the end of a ride or brick. Started last summer after a 5 hour ride with a 1 hour run. Only happens on my long workouts and not every time.

It continues for about an hour after the end of the workout regardless of what I do.

It is not stomach orlented - more windpipe and lungs. That is why I though of dehydration... but it feels like my body is very tired of breathing.

Not really pain... just irritation.

Not other symptoms other than feeling wiped out - like most long extending workouts.

I wonder if the body is just telling me that I have pushed the workout far enough.