"In nature there are neither rewards nor punishments -- there are consequences." - Robert Ingersoll
The parallel to Ultrarunning is pretty obvious. If you are undertrained for the distance, don't carry enough water, fail to have the right gear with you...BOOM. You blow up, figuratively. How badly you blow up depends upon how poorly you planned.
Not in a judgmental way, but just as simple a cause-and-effect result.
Or as I recall from my early Sunday School Bible training as a kid, a phrase that I use daily:
You reap what you sow.