I mean, he didn't run. 45km a day, when you walk 8 hours per day, is about 5.6kmh, which is absolutely doable for humans. Still, doing that every fucking day for an entire year is a stunning effort. I've been on hiking trips where we did 40-50km each day for three days and I needed a few days to recover. Oh, and I didn't hike through the continent known for its heat and deserts and wars.
Edit: I stand corrected. The guy is even more of a beast.
You can follow him on Strava and see all his runs, looks like he was doing up to 80km a day. On the 3rd of April he did 85km and the next day 81km. Insane!
Edit: his longest run according to Strava was 110km
Oh he did way more than that, and faster than walking. Come on, he did run.
It's been all over the place, but his typical run the past month or so was 75km at 7m:30s/km pace (8km/h). In the beginning he was doing ~50km runs at 5m/km pace (12km/h). I think the slowest I've seen him doing is 9m:15s/km pace (6.4 km/h).
He absolutely did run, but usually at an endurance pace, not at a race pace.
He had struggles in the beginning, but his aerobic fitness is probably astronomical by now.