Running (Specific endurance) 8:07:00  43.8 mi (11:07 / mi) +3267m 9:02 / mi
slept:6.5 shoes: S/lab ultra 4/21
Housekeeping: I started running from my car, not the trailhead, which added 1.5 miles to the usual R2R2R route. I stopped my watch when picking up water, swimming in the river, waiting for mules to pass etc (elapsed time 8:37). But despite that the supported FKT of 7:25 seems very do-able, especially considering how insanely hot it was, how much water I had to carry and that I really wasn't rushing at all.
Felt average running off the south rim. I didn't feel that great at all on the long gradual climb to Cottonwood (mile 15). Nothing specific, I just didn't have much energy. I felt much better on this part on Monday. I started to feel better again when the climb got steeper. I really enjoyed the north rim. Green, plenty of shade, completely different to the south rim. Although the final 2 miles to the top were on deep sand which was hard work. On the way back down again I started to really feel the heat, but I felt pretty good. 43°C on the clock at Phantom Ranch. Dipped in the river before the South Kaibab climb. I started with 2.5L this time which turned out to be about right. I was surprised that I actually felt fairly good for the first few miles of the climb. Probably better than Monday. Ran the first 5 miles, then started to feel a quite wobbly so hiked a lot of the final 1.5 miles to the top. I presume I was really really hot, but I had actually stopped feeling hot and was almost shivering. I guess thats what heatstroke feels like. Anyway, it didn't seem safe to not back off. Once I got to the top I was back to normal pretty quickly.
One slight niggle on the lateral side of my right foot. I only felt it on the long downhill from the north rim to the river but not at all the rest of the time. I remember feeling it on Sunday (it was so minor I forgot to mention it) and presumed i'd tied my shoes too tight. It kind of feels like a bruise.
I wasn't keeping track of how much I drank, but I think it was close to 10L in total. Mix of Spring drink and water. Took an S-cap every hour. Gels, some dates, a bagel. Works out around 70g/hr.
Pretty pleased with this, especially as I felt stronger towards the end (until the wobble at least). I feel quite confident with the heat/ hydration/ electrolyte stuff. It's reassuring that no part of WS will be as hot for as long without aid station ice.