I’m currently doing the training plan for Colorado State Championship road race 35+ 4/5. I chose this training plan because the course seems pretty similar to the Texas State Championship course. This week has 4 x 5 minute VO2 max intervals. Now, if i get out to train by 6pm, it’s still around 100f here in Central Texas. This seems to have an effect on hr, as the body seems to have to work harder to achieve the same power in the heat. Is it better to do these on the trainer or should i suck it up and ride in the heat?