And one more thing...

After a few runs now where I've had the chance to stop at a hydration station and mix some water up with Gatorade (vs. just using water fountains to hydrate), I seem to get tummy aches. I can only assume this is from the Gatorade, as that has been the only difference in my runs. I bought some shot blocs, but haven't tried them yet. Will this be sufficient for electrolyte replacement on those longer runs? Has Gu worked better for people? I've never used this type of replacement product so I'm curious as to people's reactions to them. Thanks for any info you can offer!