Whoever came up with the "dog days" tag didn't know what he was talking about. Sultry summer days aren't necessarily your pet's favorites.

Most of us assume that as we suffer with sunburn, mosquito bites, heat rash, and all the other woes befalling humans when the thermometer reaches 90, our resident canines are oblivious to misery as they busy themselves lolling their tongues and stealing licks of ice-cream cones.

Hardly, says veterinarian and author Dr. Michael Fox, director or the Humane Society's Institute for the Study of Animal Problems. If owners don't take a few precautions to protect their pets from hot-weather hazards, he warns, summer can be a miserable experience for animal and owner alike.

As for humans, diet and exercise should be curtailed during very hot spells.

"Most dogs will self-regulate their diets," says Fox, "but some will overeat, and you should take care to see that the dog gets fewer calories to meet its reduced requirements."

Exercise also needs to be specially tempered to meet the dog's respiratory capacity, which is far less than human's. Dogs can't sweat, and panting is the only way a dog can regulate its temperature. It the temperature outside the animal is higher than the temperature inside (usually around 101 degrees), it is likely to have breathing difficulties. (That's why it is so dangerous to leave a dog in a parked car when it's humid or the temperature over 70. Even in the shade with the windows cracked, a car's temperature inside can climb to more than 110 degrees in a few minutes, causing brain damage -- or death -- while you run in and pick up that quart of milk.)

Dogs, claims Fox, can still make excellent jogging companions. He recommends a good conditioning program for those just starting out (dogs as well as people), building up slowly. If you're going to job with your dog, keept it on a leash, and run only in the early morning or late evening, when it's coolest.

Beware of hot pavement. Your dog does not come equipped with thick socks and shoes and can burn his feet.

Also beware of the signs of heat stroke: heavy panting, a tongue that's deep red or purple, a dazed expression, and abnormal pupils. If your dog exhibits any or all of these symptoms, cool him off IMMEDIATELY, by submerging him up to his neck in a tub, or washing him down completely with a hose. Them get him to a vet.

Fox warns also that short-nosed breeds, like Pugs, Pekes, and bulldogs have more trouble cooling air and are unlikely to become successful joggers.

The beach is a particulary popular place for owners to take their dogs, but if you must have Spot at your side, be careful to keep him in during the hottest part of the day.

"Basically, you should take the same precautions with your dog that you would with a small child," says Fox. "Don't let it get too much sun or exercise, and make sure you take along some fresh water."

Don't assume that your dog can't get sunburned, either, just because it has a fur coat. White dogs, collies, and any dog that's been clipped is susceptible.

If your dog swims, remember not to let him get overtired. Most dogs, especially water dogs like labs and Chesapeake Bay retrievers, will continue to try to fetch that ball or Frisbee even when they've passed the point of being able to make it back to shore safely. Any ocean swimming should be followed by a fresh-water bath, to avert the dry-skin problems caused or exacerbated by salt water.

Also remember to take off your dog's flea collar before he goes in the water. The chemicals which kill fleas are intensified when the collar gets wet, and it can kill the dog along with the fleas.

Speaking of fleas . . .It seems Fox deals with these most unwelcome summer visitors the same as the rest of us -- unsuccessfully. Nevertheless, he recommends powders and dips, as well as a good house fumigation twice a summer. And as if the incessant scratching isn't bad enough, some dogs with flea allergies develop "hot-spots," open sores caused by the dog chewing at itself.This calls for veterinary attention at once to prevent infection.

While fleas can't be prevented totally, some other nasty types of insects can be warded off if you apply a small amount of insecticide (liquid or stick, not spray) to the tips of the dog's ears and its head.

Summer, lest you need reminding, doesn't have to be a dog's life.