The answer is the warm water and massaging bubbles coming from the hot tub Dennis gets in are the contact and temperature receptors. These are located in the surface of the skin. These receptors promote relaxation and relief from stress. When water is consumed and/ or applied in the external parts of the body, this is a great way to detoxify and hydrates the body. When the body is soaked in different temperatures, this can give good effect to the nervous system and may also help in the proper blood flow to the heart, lungs and to the entire body.