Maybe it's the loneliness of the long-distance runner that prompts so many training for the upcoming marathon to run with their dogs.
But marathon training isn't necessarily a healthy workout for your pet. "People think they're doing their dogs a favor by running long distances with them, but they're really not," says Bill Berloni of the Humane Society of New York. "Experienced marathoners have built up an endurance; their joints can take a lot of pounding and pressure. Dogs aren't made the same way."
Yet dogs don't complain - and therein lies the problem. "Your dog wants to make you happy, so he won't tell you if he's in pain - he may even ignore the pain," says Dr. Arnold Plotnick of the ASPCA.
The most common canine injury, says Plotnick, is a torn cruciate ligament, which causes arthritis and may require surgery. Still, if running together is quality time you and your dog simply can't live without, here are some pointers for exercising responsibly.
Rest and rehydrate
Marathoner Jenny Hassler knows the importance of rest stops. The Manhattan woman, who is deaf, runs three times a week with Ripple, the Labrador-pit bull hybrid who is her certified hearing dog.
"If we are doing a two-mile run, Ripple can go straight through just fine," says Hassler, who plans to run the road race on Nov. 7, "but if we do a longer run, like five miles, I'll stop twice to give her water and let her have a little break. If we go longer, I'll stop more often."
Experts suggest running with your dog on soft terrain because it's much easier on their joints. Look for fountains, as Hassler does, or carry bottled water so you can keep your dog hydrated.
If you notice your dog panting heavily or limping, vets say, stop and check all four legs and paws - the animal may have injured a paw-pad on broken glass, for example. If that's the case, stop running and take the dog to a vet immediately.
And avoid exerting your dog when it's extremely hot or cold to prevent heat stroke or hypothermia.
Born to run
If you're looking for a running companion, of course you have to consider the dog's health, athletic predisposition, age and history. Assuming everything is in order, your best bet is a large, long-limbed canine with a high energy level. Tom Bradley of New York's Westminster Kennel Club recommends Labs, golden retrievers, pointers, Weimaraners, Dalmatians, elkhounds, foxhounds, vizslas, Brittanys, Akitas, Samoyeds, Siberian huskies and malamutes. On the mutt front, Berloni suggests shepherd mixes or any healthy hybrid "in the 50-to-70-pound range, because a dog that size can pretty much keep up with a human's pace."
Don't expect heroics from bulldogs, pugs or other easily winded breeds. Ditto short-legged or toy-size dogs like Yorkies and dachshunds.
"When we walk a Dalmatian two blocks, it takes it 10,000 paces," Berloni explains. "For a Chihuahua, the same distance takes 50,000 paces, so the dog's doing five times as much work."
Slow and steady
It's hard to exhaust some dogs, as New York State Assembly member Pete Grannis discovered while running between four and six miles, twice or three times a week, with Princess, his vizsla.
"She wonders why I don't go further," Grannis laughs. "I'm too slow for her!"
But don't expect to turn your couch hound into a greyhound in a day, especially if he's overweight, experts say. Start with long, brisk walks before gradually working up to short sprints, jogs and longer-distance runs.