I'm probably completely paranoid as it's most likely due to the temperature there, but after adopting Koda I noticed that he panted an awful lot, and it wouldn't take much (I'd let him out in the backyard, he'd walk around for two minutes, come back in, and pant for fifteen). This was during February when I adopted him, so the weather was in the 60's. Point being, I found it rather odd, and after getting him checked out at the Vet (He was a stray), got his shots, and a heartworm test...He came back positive. That explained the panting. It's the strain on his heart and lungs.
As I said, I sincerely doubt Kaiah has heartworm, especially
at 7 months, as it takes 6 months from the time a dog is bitten by a mosquito for it to mature into adult heartworm, but maybe have a test done? Just to be safe? Unless you have Kaiah on preventative, then it most definitely has nothing to do with that.
Geez, I really am paranoid now.
I feel like some "born again heartworm prevention speaker" or something... Oh man, someone stop me.