A Blessing of Warmth and Bubbles
( Excerpts from an article by Rebecca Robledo, contained in the February 8, 1993 issue of “Pool & Spa News”)
Spas and Hot Tubs offer much more than sensations of warmth and effervescence; for many soakers, time in the tub can bring pain relief, inceased mobility and in some cases, even healing. How does this happen? What do hot water and jet action really do to the human body?
As anyone who has ever slid into a spa or hot tub can attest, things start happening from the very first moment of contact with the water. The most immediate sensation when settling in is one of buoyancy... followed soon after by one of enveloping warmth.
Of course, any water, hot or cold will provide the feeling of near weightlessness. What distinguishes a spa from a pool or even a cozily warm bath, say medical experts, is its high, sustained temperature, which brings about a fundamental shift in how the body’s circulatory system operates.
“The heat really adds another dimension to the buoancy that water has,” says David Horay, a Berkeley, CA chiropractor and co-author (with David Harp) of “ Hot Water Therapy”.“Any warm water will provide the benefits of buoancy, but it won’t provide the circulatory and blood pressure benefits of a spa.”
Once you’ve immersed yourself in the hot water, he explains, the temperature regulating mechanisms of your body kick into gear, trying to restore and maintain a normal temperature; your heart works harder, pumping blood to the surface in an attempt to disperse extra body heat into the air. As this increased volume of blood courses through your veins, a temporary increase in blood pressure occurs.
In trying to cool itself down, the body also begins sweating at an increased rate to bring moisture to the surface of the body, where it would under normal cicumstances evaporate and lower the temperature to normal again. Because the body is immersed in hot water, howerver, the sweat can’t cool the skin through evaporation. In fact, the blood brought to the skin’s surface becomes even hotter because water is more effective than air at transferring heat.
As the blood continues its cycles, gathering more warmth from the surface and transporting it deep into the body, the soaker’s core (or overall) temperature rises quite rapidly. In 104 degree water, studies show, a spa user’s core body temperature can rise to 102 degrees Fahrenheit in well under 20 minutes.
At some point as the body’s core temperature rises and ciculation is enhanced, a spa user is overtaken by a powerful feeling of relaxation. So what’s just happened?
According to medical experts, second change in the body’s blood pressure has occurred: As the now- warmed blood spreads thruoghout the body, it causes the blood vessels to expand. This dilation lessens the resistance to blood flow, and blood pressure drops. By dilating the vessels, this warm blood has, in effect, beaten a broader path, making for an easier flow and so increasing the body’s level of circulation. As this surge of warm, nourishing blood reaches deeper and deeper into the body, Horay and Harp explain, more blood vessels dilate and your muscles relax.
“The warmth not only stimulates activity in the bloodstream, it also has an effect on the nervous system as well,” says Thomas J. Tierney, a physical therapist who is founder/ director of Aquatic Rehabilitation Systems and president of Aquatic Physical Therapy Resources in Woodridge, IL. The spa water’s heat, he explains, causes the central nervous system to become depressed, which contributes to muscle relaxation as well as temporary pain relief.
The muscle relaxation that comes with using hot water also plays a significant role in relieving pain. When a muscle is tense, for whatever reason, it also pinches on particular nerves and blood vessels that run through it, adds Horay. This makes for “an unhappy muscle”. He says, “Not only is pressure exerted on the nerve, but blood flow is restricted (which creates an insufficient oxygen supply), and lactic acid and other metabolic wastes back up. These results can all contribute to pain.”
“Hot water and pressure both help the muscle to relax, “ says Horay. “When that happens, it means that the blood running through the vessels is able to flow more efficiently,” thereby reducing pain. And furthermore, pressure is released off the nerves.
The advantage of a spa over a simple hot bath, experts also note, is that all of the above described benefits are enhanced when jet action enters the picture : The mechanical stimulation jets provide intensifies these bodily responses in individual, targeted areas of the body, helping to further reduce painful inflammation.
The pressure of the jetted water can also promote healing by stimulating the body’s healing mechanisms, reports Mike Casey, a registered physical therapist and owner of Granada Physical Therapy in Granada Hills, CA.
Along with the increased oxygen level that the tissues enjoy in a spa, he explains, the heat and the pressure from the jets can raise the level of anti-bodies and white blood cells that provide the body’s defenses. These natural bodily defenses then “destroy the bad cells” around an injured area and help stimulate the formation of new tissue.
In addition, as heart rate and respiration are increased, the blood carries more oxygen to the body’s tissues, allowing them in turn to increase the rate at which they can eliminate metabolic waste products.
“When a muscle relaxes, its fibers become spaced far enough apart so that the blood vessels have no problems transporting the volume of blood necessary to flush out metabolic wastes and replace them with oxygen and other nutrients,” says Horay.
“By maintaining a healthy muscle,” he continues, “Not only can you relieve pain, but you can also prevent pain as well as susceptibility to certain injuries. By relaxing the muscle with hot water, you can prime it for stretching exercises, range of motion exercises and other gentle exercises that help strengthen and stretch the muscles out.”
For many spa users, muscle relaxation and pain relief, whether it’s from the stress and aches of everyday life or from the chronic pain and stiffness experinced by those who suffer from diseases such as arthritis, are the most important benefits of soaking. Spas also can play a critical role in directed, short or long term therapy programs for the injured and the ill, offering an environment in which it is easier to exercise muscles without strain or additional injury.
The soothing water action can do more than provide relaxation and pain relief. According to Rosalind Cartwright, director of the Sleep Disorders Service and Research Center, “Sleep deepens as body temperature falls. As a result, she recommends in the newsletter “Bottom Line Personal”, that people who suffer occasional sleeplessness, especially if it is induced by pain, can help themselves by soaking in water about 103 degrees F approximately two hours before bedtime.