[xiainx]

Don't forget that they were also almost 9,000' above sea level, carrying heavy backpacks (probably at least 25 pounds), and breathing in wildfire smoke. The AQI in Mammoth was in the low 200s on Sunday.

Also, they had 7 days to complete the rest of their hike. I suspect the stats for the hike out weren't too difficult, but the cumulative effects were.