The team opened camp as extreme heat began to move in over the area.
Players hit the field before the heat index hit triple digits.
For the veterans, training in the hot weather is something they have prepared for but for some of the rookies it's an adjustment.
"Coming from Los Angeles, California, there's not that much humidity. Coming from Oregon, there's not that much humidity either. Just trying to get my body adapted to that environment," said Chiefs rookie De'Anthony Thomas.
"It seems like every year, camp just keeps sneaking up and sneaking up. We only had four weeks off this year, so it was very important for guys to go home and come back in the best shape you possibly can," said Chiefs quarterback Chase Daniel.
The team's first public practice will be held Thursday.
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