Heat adaptation during race week

My question is about heat adaptation. I was reading Jason Koop’s book on training for Ultrarunning where he talks about heat adaptation. Approaching the race, he suggests something that follows training tapering, a block of heat training out in advance of the race, then cutting back considerably during race week. Another recommendation is to arrive a week or more early.

My specific situations are Ironman 70.3 Hawaii (“Honu”), in early June, and Ironman Cozumel, in November. I live in Honolulu and am told that Cozumel weather is very similar. I have done Honu several times and find the heat along the Kona coast a challenge, even in June.

I have always stayed in an air conditioned condo, virtually the only option up near the race location, about an hour’s drive north of Kona. Lava fields, grass, and goats. Hot and dry.

I know the two most important strategies will be fitness and hydration. On top of that I can schedule some of my bike and run workouts to start later in the morning, well after the sun is up. But this increases the stress from the workout, and getting the right balance is a challenge. Koop prefers a heat session immediately after training, so as not to reduce the training quality. Not sure I’ll have time, but spending an hour on the beach might work!

My specific question is about how much time to spend outdoors during race week. I have a variety of workouts planned, all short duration, with some race specific intensity. Other than that, will I be better off staying cool indoors, getting plenty of rest, or should I spend a few hours outdoors in the heat? If you have Koop’s second edition, the example in figure 7.9 ends heat training four days before race day.