There is a rule of thumb out there that post-exercise weight should not be more than X percent below your pre-exercise weight. In a 2 hour run this morning I lost 5 pounds, and that seems like a lot.
What’s that rule of thumb?
Here’s a short article on fluid loss and exercise from the University of North Carolina Medical School:
http://www.med.unc.edu/medal/olympicgold/fluidintake.htm
Here are a couple of excerps:
“…athletic performance will begin to suffer after a loss of just 2-3% of body weight. After losing 5% it is common for a person to begin feeling nauseous, dizzy, or sick.”
“After losing 7-10% of your body weight a person is in serious danger and may need hospitalization.”
Richard