Thanks all. Appreciate the feedback. After this past weekend (40 mile ride +45 minute brick and then a 90 minute run), I suspect I’m teetering on the edge of overtraining and burnout. while the heat plays a role, it just doesn’t seem sufficient to explain how something that was “comfortable” is now be hard – and I’ve done it before with run training. My suspicion is that I’ve been biking too hard on the long rides (effectively at goal race speed although perhaps not race HR) and it’s now taking its toll.
Anyway, 3 weeks from the race (not doing Rev3) so tapering begins soon. Hopefully dialing it back will help get everything back in place.