Hydrotherapy is the practice of using heated water for pain relief and management—and the best hot tubs promote health and wellness with hydrotherapy. Hydrotherapy is important, having the warm water massage deep into your back and all the health benefits that it gives to you. A hot tub relaxed muscles and can be used before or after exercise. As little as 20 minutes in a hot tub can help to relax tense muscles and relieve anxiety and stress. The heat of the water makes the blood vessels dilate resulting in an increase in blood circulation.