The real problem is exercising after diving, as you may increase the formation and travel of microbubbles.
The most recent research (check DAN’s site for actual article) is that exercise 24 hours prior to diving actually decreases the incidence of DCS. However, I do not think
by exercise they meant an ironman. I would think there are a lot of micro injuries and muscle tears that may be affected by diving.
But the big issue as has been mentioned is dehydration and fatigue. Someone on ST I think was a coach of an IM COz athlete that dove a couple days after IM Coz and got bent, and the diagnosis was exercise induced DCS. I was surprised as there was at least 24+ hours or more between the IM and diving. The science is still sketchy on DCS. (ETA - whoops - thread linked, was diving before…, still find that odd getting “bent” Sunday during IM from a Thursday dive… and frankly don’t buy it… bubbles don’t last that long)
If it were me, I’d take at least one full day off, hydrate well, and dive conservatice profiles using EANx.