Thanks for your reply. We've been walking her for six weeks, 5 days a week before it happened. We have two dogs, and we let them do some sniffing when we walk, but not too much as the main purpose of the walking is to lose weight. Her panting seems worse in the house than outside, but maybe it's because of the confined space. She's been licking and chewing at her one paw, and I read that could be a sign of allergies, which can also cause panting.