Advice wanted/needed for big hike. Not prepper related

[Ranger]

is it the white rose walk you're doing by any chance? did that one about 30 years ago with a bunch of lads from blaydon youth club. one of them had to be casevac'd with heat exhaustion after about 9 miles.
if you're carrying a pack i wouldn't try jogging as this would give your knees and ankles a hell of a pounding and could cause injuries/ problems. better a good,steady pace from the off.