Hot Baths --- How They Can Cure Various Ailments

In language, ritual, and daily hygiene, we mark our kinship to the many people who took themselves to Spa, Bath, Buxton, Plombières, Lourdes, and Baden. But few of us today take baths to cure paralysis, ease gout or rheumatism, soothe an ulcer, or treat ailments of the liver or the heart. Bathing for medicinal purposes went out with horse-drawn carriages, a quaint but outmoded practice of people less sophisticated than ourselves. The question we must pose is whether medicinal bathing was also an effective technology bypassed by subsequent developments or whether it was a form of quackery that resulted in mass delusion. Were all the doctors who presided at mineral springs taking advantage of the sick people who flocked there? Were all the people who swore by their bathing regimens simply deceived? Or was the proverbial baby tossed out with the bath water when balneotherapy, as it is called, was finally discarded by the medical profession?

Around 1983 Drs. J. P. O'Hare, Audrey Heywood, and their colleagues at the Royal Infirmary in Bristol, England, decided to try to answer these questions. Experts in the physiological effects of head-out immersion (sitting in water up to the neck), the team decided to test the physiological effects of an actual mineral spring bath. In what Harold Conn, a professor of internal medicine at Yale, has called a "delicious" episode, O'Hare, Heywood, and the rest of the team approached the Bath City Council for permission to use water from one of the hot-spring baths. These baths, along with all other therapeutic spas in Great Britain, had been closed a number of years previously as a cost-cutting measure, and public funds for their medicinal use had been withdrawn. Though unable to use the baths on site, O'Hare obtained permission to cart some of the spa water to Bristol.

The research quickly became an adventure with distinct overtones of a Monty Python comedy. O'Hare's team pumped five hundred gallons of Bath mineral water into a "bowser," or water tank on wheels, and hauled it to the Bristol Royal Infirmary by taxi. Once there the scientists tried pumping the water straight from the tank in the parking lot to the immersion laboratory five floors above ground. In a parody of scientific writing, they reported that, unfortunately, "pump failure supervened," and "attempts at resuscitation failed." Not to be deterred, however, a team of "healthy volunteers" worked up a good sweat by carrying the five hundred gallons of mineral water into the building by hand. By this time clearly aware of the comic nature of their enterprise, the team even made a photographic record of the project's staggering steps.

Once the experimental baths were filled, O'Hare and his colleagues reënacted a spa "cure" on eight unidentified subjects (evidence strongly suggests that they were the eight team members themselves). Like patients at Bath in the eighteenth Century, each volunteer drank water upon waking and spent the morning immersed up to the neck in a warm (35 degrees centigrade) mineral-water bath. Periodically the unimmersed researchers drew blood, collected urine output, and monitored the volunteers' blood flow and heart functions.

As the measurements accumulated, O'Hare, Heywood, and the others recognized their similarity to experimental data they and other investigators had gathered over the previous decade for quite other reasons. One of the earliest studies on record of the physiological effects of prolonged head-out bathing was performed by the American physiologist H. C. Bazett around 1920. Bazett observed that a marked diuresis, or increased urinary excretion, was one of the most characteristic effects of such baths on healthy men. Further study demonstrated that whether the water was cold, tepid, or warm made no difference in this effect, but full immersion of the trunk of the body did. Partial immersion of the limbs alone, or even the shallow immersion of a home bathtub, did not cause increased urination. Sitting up to the neck in a pool for a few hours, however, clearly increased the excretion of water, salts, and urea, the chief components of urine.

The true novelty of the O'Hare study is that it was the first to link spa therapies with the known physiological effects of bathing and conclude that such therapies in the past may therefore have had true medicinal value.

The sort of therapeutic value it had largely depended upon the physiological effects of water immersion, which went beyond excretory functions. Because all of the body's systems are integrated, the excretion of water, salt, and urea necessarily affects many other functions as well, especially regulation of blood volume and pressure. Head-out immersion creates greater pressure on the lower body relative to the upper body. Blood is therefore compressed out of the limbs and into the trunk, like toothpaste in a tube squeezed from the bottom up. Volume receptors in the trunk sense the rise in blood volume and elicit compensatory mechanisms, such as urination, to return the volume to normal by reducing the amount of water in the blood. At the same time, because water is supporting the body, the effects of gravity are lessened, and blood pressure drops. What this means therapeutically is that people in the past who had hypertension (high blood pressure), circulatory problems, or one of the many diseases in which fluid is retained probably benefited from prolonged bathing in spa waters.

During the 1970s, recognition that immersion affects control of blood volume led Murray Epstein and other investigators, including Daniel Bichet of the University of Colorado Health Sciences Center, to use it as a research tool in the study of specific diseases characterized by blood-volume imbalances. These include liver, kidney, and heart ailments resulting in excessive fluid retention. Cirrhosis of the liver results in retention of salt, decreased urination, and the consequent buildup of fluid (as much as twenty-eight liters!) in the tissues of the abdomen, a condition known as ascites. Dropsy --- what we today call edema --- is most often associated with nephrotic syndrome (a degeneration of the kidneys) and congestive heart failure, both of which can cause very noticeable swelling of the limbs due to fluid retention. (If you ever noticed that Great-Grandma's ankles looked twice as fat as her shoes, she probably had some form of dropsy.) Without intervention, both edema and ascites can become progressively worse, because the body "misinterprets" what is going on. Buildup of fluid in tissues can result in decreased blood volume, which the body's sensors read as a signal to increase fluid retention. For reasons that are still not fully understood, however, in disease states the additional fluid moves inappropriately into body tissues rather than remaining in the blood. A vicious cycle that can lead to death begins.

Most modern cases of liver disease complicated by ascites can be satisfactorily treated with drugs that increase urination. But patients with refractory ascites, unresponsive to conventional treatment, pose a special problem. Some physicians wondered if water immersion could be manipulated clinically; in other words, could the diuresis observed in research subjects with ascites --- as modest as it was --- be used to control or cure the condition? In one case reported in 1987, a middle-aged tax inspector with ascites failed to respond to drug therapy. Over the course of some ten days he took three prolonged up-to-the-neck baths along with drug therapy and experienced the complete elimination of his ascites. The physicians responsible for his treatment --- and they included the Dr. O'Hare who tested the mineral waters of Bath suggested that "the use of ... diuretics combined with water immersion is a safe and effective method of treating those cirrhotics with ascites who fail to respond to conventional treatment." Subsequently, physicians in Germany, Poland, and the former Czechoslovakia repeated the clinical combination of diuretics and water immersion with equally beneficial results.

Early in the 1980s immersion was also seriously considered as a medical therapy for patients suffering from a range of kidney diseases. Experimental research by two different groups indicated that nephrotic patients experienced much the same physical effects from immersion as the normal or cirrhotic bather. Some patients lost up to two kilograms of fluid in the form of sweat as well as urine, which brought about an obvious diminution of edema. Even those who experienced no major fluid loss felt subjective relief from swollen ankles. The researchers concluded that prolonged bathing was not only simple and therapeutically promising but also psychologically beneficial. With some success physicians have even turned to water immersion in the attempt to reverse hepatorenal syndrome, a kind of kidney failure due to liver disease that is almost always fatal...

These modern studies tell us that for certain diseases involving fluid retention deep-water immersion was in the past --- and still is today --- an effective physical medicine. The surprising thing is that other diseases, some of which no longer plague us, may also have responded to bathing. Here we rejoin Audrey Heywood, a member of O'Hare's Bath water team, who reasoned that if urinary excretion of salts benefited conditions such as hypertension, the excretion of other substances may have effectively treated other diseases. She began by delving into the records maintained at the Bath Hospital since the early eighteenth Century to see what physicians in the past had claimed to cure. She quickly found that one form of paralysis in particular, known as colica pictonum, apparently responded well to spa therapy.

Unheard of today, colica pictonum was characterized by a short episode of severe abdominal colic (paroxysms of pain), followed by a permanent palsy, or loss of sensation and control, in the hands or arms. Of the paralytic patients treated at Bath, seven percent suffered from this condition, and most were considered incurable by other doctors using other methods. According to hospital records, resident physicians believed that bathing in Bath waters completely cured almost half of these colica pictonum patients and obviously benefited nearly all. Heywood's next question was why spa therapy should have served these patients so well. She found her clue in the cause of the disease.

In 1768 it was recognized that a number of palsies initially thought to be distinct from one another and from colica pictonum were, in fact, all caused by chronic lead poisoning. Since Roman times lead poisoning had been common in Europe, due to the use of the metal in water pipes, earthenware, cooking pots, pewter plates and tankards, cosmetics, hair dyes, and medicines. Lead absorbed through the mucous membranes or skin preferentially concentrates in the nerves, leading to such symptoms as uncontrollable shaking, loss of sensation, weakness in the limbs, numbness, deafness, impotence, memory loss, and confusion. Many cases of colic, paralysis, and abnormal mental behavior throughout the ages were therefore probably caused by lead poisoning in one form or another; in the eighteenth Century it was often the result of drinking rum and other liquors fermented in lead stills.

Once Heywood knew that colica pictonum was caused by lead poisoning, everything else fell into place. First of all, she knew that one of the substances excreted during immersion is calcium. Second, she knew that ingested lead replaces calcium in many physiological systems. Perhaps, she hypothesized, bathing had the same effect on lead in the body as it has on calcium. This led to another experiment. A new immersion study was undertaken in which the amount of lead excreted in urine was measured during three-hour baths in warm water up to the neck. The results confirmed that excretion of lead, as of sodium and calcium, does increase during bathing. Although the amount of lead excreted in one three-hour bath is small, several such baths per week over some twenty-four weeks --- typical for a cure at Bath in the eighteenth Century would have significantly reduced the amount of lead in the body. Drinking the waters, an additional mode of therapy at most bathing sites, would also have increased the amount of urine produced and therefore the amount of lead excreted. As long as additional ingestion of lead was avoided, as was likely to be the case for patients following the regimen of eating and drinking recommended by spa physicians, the paralysis of colica pictonum could be completely reversed, just as the Bath records indicated.

Heywood went on to conjecture that this simple internal cleansing of the body by repeated bathing may have brought relief from other symptoms of lead poisoning as well, such as lassitude, headaches, and infertility, all of which were common complaints among people attending European spas in the past. Perhaps most striking is the connection between lead poisoning and gout, a condition in which excess uric acid crystals are deposited in the joints of the big toe, the ankle, and the knee, causing protuberant swelling and acute attacks of pain. Today we understand gout to be primarily an inherited disorder, resulting from the inability to metabolize or break down an excretory product called uric acid. Small, regular doses of lead can also induce gout in susceptible people.

In the eighteenth Century this sort of gout appears to have reached epidemic proportions among wealthy English landowners and merchants with an excessive fondness for port contaminated with lead from storage in lead-lined casks or from contact with leaded pewter. Indeed, the image of the corpulent, well-to-do man, his foot wrapped in bandages, was indelibly etched in satirical scenes of spa towns like Bath. Deepwater bathing probably reversed cases of lead-induced gout by increasing the excretion of the metabolic poison. Inherited forms of gout, usually associated with an inability to urinate copiously, may not have responded as well to immersion. However, if the sufferer also drank large amounts of water, as was recommended, even inherited gout may have been somewhat alleviated, since any induced urination would also mean the excretion of uric acid. Spa therapies were certainly prescribed for gouty patients through the 1930s in the United States and continue to be used today in conjunction with drug therapy in France, Germany, Italy, Poland, and Russia.