Swimming and hydrotherapy: low impact exercise for dogs

The principle is buoyancy: a submerged body receives an upward push proportional to the volume of water it displaces, and that push counteracts gravity. The more of the dog is submerged, the less body weight bears down on paws, hips, knees and spine. During swimming, with the body almost entirely underwater, joint loading drops markedly compared with walking or running on land, where every footfall sends a force spike through the limb.

At the same time, moving through water demands more muscular effort than moving through air at the same speed, because the resistance of the medium is far higher. A swimming dog works the leg, back and core muscles to hold its position and generate forward thrust, and the cardiorespiratory system responds with a heart rate that climbs quickly. The result is an exercise that builds endurance and muscle tone while keeping joint load low, a combination that is hard to achieve on land without the risk that running or jumping carries.

Swimming applies to very different situations, from recovering after orthopaedic surgery to keeping a sporting dog in shape between training sessions, but it is not a neutral choice: some conditions make it risky or call for close supervision. The table separates cases where water is generally an ally from those that need a vet's opinion first or should avoid it altogether.

Not everything called swimming is the same activity. Free swimming, in the sea, a lake or a dog friendly pool, depends on the environment and the animal's spontaneous behaviour: it is the most accessible form but also the least controllable. The underwater treadmill, typical of rehabilitation centres, allows the water level, belt speed and duration to be adjusted precisely, often keeping partial ground contact rather than true swimming. Hydrotherapy guided by a professional, in a rehabilitation pool with hands on support, combines swimming with targeted exercises under the constant supervision of a trained veterinary physiotherapist.

For a healthy dog swimming for fun, free swimming is almost always enough, provided the safety rules are followed. For a dog in clinical recovery or with an orthopaedic diagnosis, the underwater treadmill or guided hydrotherapy offer a level of control that free swimming cannot match, which is why serious rehabilitation pathways favour them in the early stages.

Water introduces risks that do not exist on land, and many of them are prevented with simple choices applied consistently. Some concern the environment, others the dog itself, others the equipment used.

• A canine life jacket for the first sessions, for senior dogs, for dogs unsure in water, or for outings in open water with currents or waves.
• Gradual, never forced, entry: a dog pushed or thrown into water often develops lasting fear, while entering in small steps builds confidence.
• Water temperature assessed case by case: very cold water tires a dog faster and raises risk in dogs with heart or joint problems, but there is no single threshold that applies to every dog, setting and season.
• Attention to currents, tides and waves in the sea or a river: a dog that swims well in a pool can struggle in open water even when conditions look calm.
• Choosing between salt water, chlorinated water or lake water based on skin, ears and any past irritation: each has different advantages and drawbacks and should be judged for the individual dog, not by default.
• Drying and checking the ear canals after every session, because water trapped in the ear promotes ear infections, especially in dogs with floppy ears or an existing predisposition.
• Constant supervision: never leave a dog unattended in water, even one that swims confidently and even in a private pool.

A less well known but real risk is repeated water ingestion during play, for example when a dog snaps at splashes or drinks while swimming: excessive amounts of water swallowed in a short time can cause hyponatraemia, a dangerous dilution of sodium in the blood. Vomiting, abdominal bloating, unsteady gait or lethargy shortly after a water session should be treated as an emergency and brought to a vet's attention right away.

A good start does not aim to get the dog swimming as fast as possible, but to build a positive experience that holds up over time. The sequence below applies both to a puppy discovering water and to an adult dog that has never been near it.

1. 1

   Pick a calm, shallow setting

   A gently sloping shore, a quiet dog friendly pool or a dedicated tub work better than a choppy lake or a wave washed beach for the first contact.

2. 2

   Let the dog explore without forcing it

   Get the paws wet first, then the belly, letting the dog set the pace. Food and a familiar voice help; a tight lead and pushing do not.

3. 3

   Use a life jacket on the first outings

   It supports buoyancy and lets the dog focus on paddling instead of staying afloat, cutting down initial stress.

4. 4

   Stay close during the first swim

   A hand under the belly or beside the flank gives physical and felt security, especially in the first metres while the dog finds its leg coordination.

5. 5

   Keep the first sessions short

   Better to come out of the water while the dog is still interested than to wait for the first sign of tiredness: the next session will be easier to offer.

6. 6

   Increase duration and difficulty gradually

   Only after several positive outings should you extend time in the water or introduce light currents and longer distances, always watching how that individual dog responds.

The right length for a session depends on age, physical condition, clinical goal and the individual dog's fitness level, and there is no number of minutes that works as a general rule: for a dog in rehabilitation the programme is set by the veterinary physiotherapist, while for a healthy dog you start with short sessions and lengthen them based on the observed response, not a fixed schedule.

1. Watch the breathing during and after the session: it should settle within a reasonable time, without prolonged panting.
2. Check the gait on leaving the water: a new limp or hesitation compared with before should be reported to the vet.
3. Note body weight and girth at regular intervals if the goal is weight loss, to see whether the programme is working.
4. Log the actual active swimming time of each session, not just the total time spent in water, distinguishing real swimming from simply wading.
5. Track any episodes of ear infection, skin irritation or digestive upset after sessions, to see whether the setting or protocol needs to change.
6. Watch the dog's interest over time: falling enthusiasm for an activity it used to enjoy is a signal worth noting, not just a mood.

Keeping these observations written down, even in a simple form, makes it easier to tell real improvement from impression, and gives the vet or physiotherapist concrete data to adjust the programme instead of rough memories gathered on the spot.