Intense afternoon exercise can increase body temperature and delay the circadian clock, leading to later sleep and wake times.

“You can also shift your clock by engaging in exercise in the four hours after your temperature minimum to wake up earlier on subsequent nights”

“if you exercise very intensely, so this might be weight training or running or some other very intense exercise, typically that's going to further increase your body temperature. ... And it's going to so-called delay your circadian clock. It's going to make it such that you want to fall asleep a little bit later, maybe even a lot later.”

“Some people find if they exercise late in the day, they have trouble sleeping. In general, intense exercise does that, whereas the kind of lower intensity exercise doesn't.”