JODIELYNNRENK asks: "I have a question regarding the effect, if any, on altitude on senior dogs. I have 2 dogs that are 12 years old; a lab and a lab/shepherd mix. I recently relocated to Colorado from Wisconsin, so we are at least 5,000 feet higher than we've ever been! I'm wondering if this change has any type of effect on my dogs, considering their ages. I do notice they seem to breathe more heavily, but I don't know if this is just because of their older ages or if the altitude could be making things more difficult for them."