If your dog has traded morning laps around the yard for long naps on the couch, you are not imagining the slowdown. Adult dogs sleep a lot to begin with, usually 12 to 14 hours a day, and puppies and seniors need more. A handful of ordinary things can push that number higher, and some of them are worth a call to your vet.
Weather is the simplest place to start. Warm, humid days turn a familiar walk into hard work, especially for older dogs, heavier dogs, and flat-faced breeds who already struggle to stay cool. Pain is the sneakier one. A FitBark comparison found that dogs with osteoarthritis logged about a third less activity than other adult and senior dogs, and that gap often reads as sleeping more rather than limping. Age does its own quiet work too. Recent senior dog blood work is starting to show how much aging changes underneath the surface.
Something at home can do it as well. A weekend full of guests, a move, a new baby, or a new pet can leave a dog flat out for days. So can plain boredom. A dog who used to get a long sniffy walk and now gets two quick laps of the block has energy to spare and nowhere to spend it.
What this means for your dog
Watch the whole dog, not just the clock. A dog who naps hard and still races you to the food bowl is usually fine. A dog who skips meals, stiffens up, or stops caring about the leash is telling you something else. Ask when the change started. Extra sleep that arrives with a house full of guests or a move often settles once the routine does. Extra sleep that shows up out of nowhere deserves a closer look. Call your vet if the naps come with vomiting, diarrhea, coughing, trouble standing, or more drinking and peeing than usual. Canine Journal keeps the fuller list of causes here. And if your problem runs the other direction, with a dog who is up and pacing at night, our piece on why your dog is restless at night is the better starting point.