We adopted a lab/golden mix that's around 1 1/2 year old. I noticed that his breathing is very rapid compared to our 6 yr old lab Chloe. It's about 4 breaths to Chloe's 1. Is this something we should worry about? I'm not sure what a "normal" heart rate is. He tested negative for heartworms before we adopted him. He had a physical by our vet after we brought him home and she listened to his heart and didn't say anything was wrong. I didn't notice his rapid breathing at that point so it was not brought to her attention. I was just curious to see if this is normal or if we should have him checked again. He gets regular exercise and is squirrel obsessed so he is almost constantly on the move. Thanks.