Not long ago, Nicole Rosell’s 11-year-old terrier mix Lily blew a disc in her neck, leaving the previously active pooch temporarily paralyzed. Surgery helped to relieve the compression on her spinal nerves, but then the hard work of rehabilitation began. Among her treatments was one fairly novel to many dog owners: hydrotherapy sessions on an underwater treadmill.

Although Lily didn’t have enough coordination to walk on land, the water was buoyant enough to support her as she took her first tentative steps. Now she’s ready to frolic. “She’s doing really well; she’s off all her pain meds,” says Rosell. “She walks a little differently, but she’s back to her playful self. I feel great knowing she’s not in pain anymore.”

Related: Caring for Your Older Dog

Rosell is one of many dog owners who have seen the benefits of water therapy first hand. She isn’t just a client, though. She’s a canine rehabilitation assistant at Holistic Veterinary Care in Oakland, California. She spends her days around the “pool” helping sick or injured dogs just like Lily.

Rehab: Not just for people anymore

Although people have known the benefits of hydrotherapy for decades, using it in dogs is relatively new. If your pooch has dog arthritis or is barely walking after being hit by a car, or if he’s older and not getting enough exercise anymore because his joints hurt, hydrotherapy might be the answer.

Exercising in water allows dogs to work most of their muscles, getting a full range of joint motion without the stress caused by motion on hard ground. After an injury, the therapy can help reverse muscle wasting caused by lack of use. It reduces tissue swelling and is considered a natural anti-inflammatory. Hydrotherapy can also provide a good cardiovascular workout.

It’s most commonly used to treat dogs with arthritis, dysplasia (joint malformation) and joint injuries, as well as dogs with soft tissue problems like tendinitis or muscle sprains. But in some cases, it’s also used to help an overweight dog get the exercise he needs to lose weight.

For overweight dogs, there’s no single fix, according to Gary Richter, DVM, the owner and medical director of Montclair Veterinary Hospital and Holistic Veterinary Care in Oakland, California.

. “They have to exercise, change their diet, and change their lifestyle,” he says, “but if you have a dog who is overweight and has trouble exercising, hydrotherapy can help.”

Related: Dog Toys: Which Ones Are Safest?

Hydrotherapy pools use warm water, which experts recommend keeping at a temperature around 85 degrees. This is warm enough to facilitate blood flow and relax muscles, but not too warm that it causes overheating.

Dog hydrotherapy has flourished for more than 15 years in the United Kingdom. In recent years, more and more U.S. veterinarians are embracing the practice. You can find hydrotherapy units at many veterinarian offices, and some facilities are set up just for hydrotherapy. To find a qualified practitioner in your area, visit the International Association of Canine Water Therapy.

Richter says the increased interest in hydrotherapy is part of a larger trend in rehab therapy for dogs. “It’s a natural carry over from the human medical side,” he says. “If someone had a knee or back surgery, no one would think of not doing rehab.” Hydrotherapy is one piece of that puzzle, he concludes. But like any other treatment, he says, “it’s all based on the individual’s need.”

Pool or treadmill for your pooch?

Your dog can do one of two types of hydrotherapy treatments. In the first, he’ll walk on an underwater treadmill. In the second, he’ll swim in a pool against a current. In both cases, a trained therapist will guide your pooch.

“We often go in with the dog, at least the first few times,” says Rosell. “We use a vest or harness system until we know they are comfortable and independent. Even if someone says their pet hates water, we can usually get them used to it. We’ve had 5-pound dogs, short-legged dachshunds and Great Danes in our pools.”

Dogs with a hind leg or hip injury (sometimes from being hit by a car) are usually put on a treadmill. This allows the therapist to control the treatment by adjusting the speed and incline of the treadmill as well as the water depth. An advantage of the treadmill is that the therapist can observe the dog’s movement from outside the pool.

Related: How to Keep Your Pooch Safe at the Dog Park

For dogs that need all-over conditioning and love to swim, a pool with a current may be the way to go. It works their whole body and may be an even better cardio workout. Some experts believe dogs are calmer and more playful in pools.

Some dogs benefit from both the treadmill and the pool.  Redd, an active Siberian husky, was ten when she tore her cranial cruciate ligament (in her knee) while playing with the family’s puppy. "When she came out of surgery I would’ve sworn she would not walk again, let alone run,” says her owner, Elaine Bild. Redd started rehab ten days later. She walked over poles, did figures eights with cones and finally made it to the underwater treadmill.

After a couple of months, Redd “graduated” from the treadmill and moved on to the pool. Today, at 14, “she runs with the youngsters,” says Bild. And she isn’t done with hydrotherapy. “She’s always loved the water so much that we decided to take her to [water therapy] every other week. She swims laps for an hour. For a dog her age it’s really good exercise.”

Tips for pet parents 

Here are some tips for dog hydrotherapy newbies:

Make sure the therapy is right for your dog. The risks are minimal, but your vet should give your dog a thorough rehab exam ahead of time to make sure your dog is a good candidate for treatment. The vet will make sure that your dog is able to handle the cardiovascular workout that hydrotherapy entails. Dogs with certain skin conditions or incontinence are not good candidates for hydrotherapy.

Ask your vet for a referral to a properly trained rehab therapist. Make sure whoever is treating your dog is trained and experienced in hydrotherapy. The pools should be clear and clean (a little fur floating in it is OK). Equally important, the therapist should be kind and gentle with your pooch.

Discuss your dog’s overall health issues. If a dog has issues swallowing, for example, the therapist will want to keep the water level well below the mouth area. “The treadmill is better for these dogs, because it offers a more controlled environment,” says Rosell.

Consider getting pet insurance. Hydrotherapy can be expensive. If you already have pet insurance, check with your provider. Several pet insurance companies will cover hydrotherapy if your vet recommends it as part of rehabilitation.

The length of the treatment will depend on your dog and the injury or illness being treated. A young dog that just had knee surgery may need treatment for a couple of months. Hip dysplasia could take up to a year of treatments. And vets say that an elderly dog with chronic arthritis may benefit from weekly or bi-weekly swims for the rest of his life.

Related: The Right Way to Walk Your Dog

Mary Purcell is a freelance writer and health researcher in Piedmont, Calif., with expertise in policy analysis. She has a master's degree in Latin American studies from Georgetown University.