@splitwdw, I work out about 2 hours every day. I am trying to figure out how much I need to drink during a long run in hot weather. I suffer from cardiac drift.
Not sure what you mean by "suffer from cardiac drift". It's a natural occurring increase in your core temperature which elevates heart rate. Happens to all long distance runners. Here are some tips on hydrating before, during and after running plus a sweat loss calculator. http://http://runnersconnect.net/how-to-run-in-the-heat/