Strong, pulsating jets and warm, bubbly water -- many people use a dip in a hot tub to unwind. For those who need justification for this relaxing means of self-indulgence, some professionals say therapeutic benefits exist.

Michael Morse, instructor in the kinesiology department at Penn State, stresses that stress relief is a primary benefit of hot tub use. "You can really relax in the water environment," he said.

Larry Kenney, professor of kinesiology, said, "In my opinion, the sole physiological benefit of hot tubs is an aid to relaxation."

John Miller, instructor of kinesiology, said the biological components involved in stress relief by way of using hot tubs include increased blood flow, oxygen consumption, capillary permeability, inflammation, cell waste and muscle contraction velocity.

Craig Denegar, associate professional athletic trainer, said although he doesn't know of any documented benefits of hot tub use, heat massage has been used for generations to relieve aches and pains.

Morse recognized that depending on the stage of the injury, hot tub use might or might not be a suggested way to alleviate pain. "It's important to understand whether the aches and pains are a direct result of an acute injury, in which case, ice is the recommended modality of treatment," he said. "In the recovery or rehab phase, the warmth can benefit any muscles in the body as the heat will enhance blood flow and improve motility."

Miller suggests taking a dip to soothe "general, mild aches and pains associated with muscle strains and arthritis."

The first component to a hot tub is hot water. Hot water "removes waste products through increase in blood flow in the long term," Miller said. But he said in the long term, the hot water will make a person feel more fatigued.

Morse agreed that hot water enhances blood flow. He said being immersed in hot water helps treat aches and pains with minimal stress on the joints due to the effect of buoyancy.

He pointed out that this benefits range of motion in all joints.

The second factor in hot tub therapy is jets. Morse said, "They act as an aqua massage, very similar to the hands of an experienced massage therapist."

Miller added, "They stimulate skin receptors which may help to block the transmission of pain messages to the central nervous system."

Both Miller and Morse suggest following up a flexibility session or stretching with a soak in a hot tub.

Some professionals remain skeptical about the therapeutic benefits of hot tub use.

William E. Buckley, professor of exercise science and health education at Penn State, said, "The therapeutic effects of a hot tub have not been established."

He added, "You may note that there are virtually no full-body, temperature-oriented therapeutic hot tubs at any sports medicine facility, hospital, etc. There is a reason for that," he said. "It feels good. That's why many people like them."