Swimming provides a great cardiovascular workout.

Reaching for floating toys, with using core body and all four legs, or just keeping afloat means your dog's heart will have to work harder than with any other activity.

In the pool the chest is under pressure from the weight of the water squeezing inwards. Each breath requires more effort, particularly when breathing in. The muscles around the chest have to work harder when your dog is swimming, and short, regular dips in the pool will improve your dog's whole respiratory system.