I have a small Chit zu my brother in law gave me, the dog is a little over a year old.

I’ve been walking him about once an hour during daylight hours, but recently, he seems to want to go on longer walks of about a mile or just under a mile, several times a day.

Can it be bad for his heart health to walk him too much?

I can't imagine walking a small dog for hours several times a day.

doubt it, always had small dogs and they let me know when they are tired from walking too much, they just LDAR on the sidewalk for a min. really the the only way to gauge their general endurance.

I have a shih tzu with a little bit of Chihuahua and she's 12. Usually walk her 1.5 miles a day, sometimes twice. I take it easier in the summer when it's hot. She's sensitive to both hot and cold, but a little more sensitive to the heat. She's about 13.5 pounds for reference, vet has always said she has a healthy heart.

I walk him for 20 or 30 minutes at a time

I too have a chit zu poodle mix. She'll keep running all day. She usually lays down out side if she is tired on her walk.

They'll let you'll know if it's too much. She'll start panting a lot and maybe just lie down on the street.

I now walk him a minimum of 3 miles a day.

.75 miles, 4 times a day

I have a highly athletic yorkshire terrier. very high test. His balls are absolutely massive. If he was a man they'd be the size of footballs. Probably got bigger junk that half the misc without even correcting for proportion. Anyway, I digress. He's the cutest, sweetest, most amazing man. He needs a LOT of exercise so I take him into the deep woods for an hour. I used to do two hours a day, but it's been cold and the sun sets too early.
He gets reluctant if he smells too many coyotes - but that's just a guess. We saw a pack of them and I picked him up and got a stick from the ground. There are a lot of them on the farm. Is there a big dog around who might be causing some concern? I found that when I acted excited I was able to overcome his reluctance. Now he is back to his usual macho self.
Anyway dogs are love. he snuggles up to me and I know the greatest joy.

I’ve been walking him a minimum of 3 miles a day, and combined with weight training 3 out of every 4 days and good nutrition, I’ve been losing a lot of weight! I’ve been living in the same rural area for two and a half years and my all time low was 274 in 2021, today I was 271.