Watsu, like reflexology, employs ancient principles used to unblock the free flow of energy through the body. Watsu combines water and shiatsu, a form of Japanese "finger pressure" massage applied to the meridians of chi. It was developed in 1980 by Harold Dull, who traveled to Japan to study Zen Shiatsu, a form of massage using stretches and touchpoints to release blockages. Back in America, Dull promoted the benefits of performing shiatsu moves and stretches in warm water.

Yin and yang describe the energy that flows through all living things. In Chinese, this energy is known as qi or chi. Yin and Yang imbalance is believed to cause stress.

A warm spa (95°–97°F or 35°–36°C) is a perfect environment for a Watsu aquatic bodywork session. Floating in water and supported by the Watsu practitioner, the Watsu receiver passes into a state of complete relaxation as gentle stretching is applied to specific points. More than just a massage, Watsu involves a series of free-flowing movements that increase flexibility and strengthen muscles.

Watsu combines water and shiatsu, a form of Japanese "finger pressure" massage applied to the meridians of chi.

The healing techniques of reflexology and Watsu are increasingly being integrated into the practices of physical therapists. Hot tub users can easily adapt the techniques of both therapies as well, to enhance well-being, health and relaxation.