The track workout, 400 and 200 meter repeats in 82 degrees. The sweat was dripping, but after 6 weeks of workouts, I seem to be adapting. Not trying to run the intervals any faster than 5k pace so I don't overcook myself. I used to destroy myself with repeats, but that's not the best way for me. I seem to be able to absorb the slower reps and I'm not too tired for the rest of the week.