Ran 18 miles Saturday morning in 2 hours and 45 minutes. Temperature was in the 70's and humidity was also in the 70's. I wore a belt that held 4 liquid bottles. 2 held water and the other 2 held Gatorade. I also packed 1 gel pack in the belt. I consumed the gel pack at about mile 14. The only real problem was that my left ankle was sore for about 7 or 8 miles. I was definitely stiff and sore at the end of this run. I could tell that just like last year after 17 or 18 miles it is more of a mind exercise than a physical exercise.