Sauna, solution to anorexia nervosa?

2010/09/01 Zarate Sesma, Jon - Farmazian doktorea. Biofarmazia, Farmakozinetika eta Farmazia-teknologiako irakasle kolaboratzaileaFarmazia Fakultatea UPV-EHU, Vitoria-Gasteiz | Txurruka Ortega, Itziar - Farmazia eta Elikagaien Zientziak Departamentua, EHU | Lasa Elgezua, Arrate - Farmazia eta Elikagaien Zientziak Departamentua, EHU | Miranda Gómez, Jonatan - Farmazia eta Elikagaien Zientziak Departamentua, EHU | Etxebarria Orella, Enrique - Fisiologia Departamentua, EHU | Rada Fernandez de Jauregi, Diego - Fisiologia Departamentua, EHU Iturria: Elhuyar aldizkaria

• Osasuna
• Medikuntza
• Anatomia/Fisiologia

Anorexia nervosa is a syndrome characterized by a person's voluntary denial of eating. Weight loss and severe alterations in body organs and systems, such as endocrine and metabolic imbalances, are evident in this disease.

Two subtypes of anorexia nervosa can be distinguished: on the one hand, restrictive anorexia nervosa, in which weight decreases by diet or high-intensity physical exercise; on the other, bulimic anorexia nervosa. In this second case, the patient ingests excessive amounts of food and ends up with vomiting.

According to the manual DSM-IV (Diagnostic and Statistical Manual of Mental Disordersen), the main criteria for diagnosing anorexia nervosa are to keep the body weight below 85% of the normal weight corresponding to age and height, to be afraid of obesity, distorted perception of the body appearance itself and the absence of rule in at least three continuous cycles. The symptoms of this clinical picture are late, increased physical activity, problems of thermoregulation, depression and risk of autolysis, problems of addiction and lack of organization of family life and social relationships.

The highest prevalence of this disease occurs in adolescent girls. In recent years the frequency of this disease has been increasing and currently one in 200 adolescents develops anorexia nervosa. Of these, 50% are completely cured, 30% suffer residual symptoms in later years, 10% become chronic and 8% die.

Many factors are investigated as causes of anorexia nervosa. However, it does not seem to be the only cause of the disease. Moreover, experts do not agree on whether they cause confusion of certain characteristics of the disease or previous facts.

Several agents can start the disease. On the one hand, the myth of thin women in the media of developed societies leads women to obsessively deal with their physique and, in some cases, develop emotional and eating disorders. On the other hand, education in eating habits that is received in the family is important. If young people are not taught proper eating behavior, they may develop eating disorders. In addition, it has been found that patients with weight problems have lower self-esteem and studies have been found that women with this problem may have eating disorders in later years. Finally, we must mention the biological causes, since anorexia nervosa is a disease related to appetite.

Although it is a multietiological syndrome, it is necessary to pay special attention to biological causes. The hypothalamus of the central nervous system, the regulating center of appetite, is responsible for the attraction or rejection of the person towards food. The changes that occur significantly affect the person's diet. Thus, analyzing the behavior of the compounds involved in this appetite control, we can come to understand the biological cause of anorexia nervosa. What's more, proposing treatments to correct changes in the hypothalamus may be possible to cure the disease.

How to cope with anorexia nervosa

There is no simple therapy to treat eating disorders. Proof of this is that five years after the start of treatment, a third of patients continue to suffer certain characteristics of the disease. Because anorexia nervosa is a serious disease and its poor outpatient prognosis, hospital treatment is necessary. However, there are patients who disagree with admission, who are considered healthy and who have no justification in any therapy.

The first goal of treatment is usually weight recovery. To do this, it is important to break the opposition climate that is generated between the patient and the family to achieve a controlled diet with psychotherapeutic treatment. Then try to maintain the weight obtained, as it is necessary to prevent relapse.

It should be noted that after the total physical recovery of the patient, the psychological alterations do not disappear. It is observed that women who have managed to recover do not have obsessive behaviors, thinking without flexibility, problems of expression of emotions, or control of self-controls and impulses. In addition, they remain obsessed with thinness and show psychopathology related to eating habits. They constantly seek perfection and are obsessed with symmetry and order.

Research on relapse prevention has aroused great hope. It has been observed that the use of psychological therapy along with fluoxetine antidepressant gives good results and reduces relapse. In addition, fluoxetine decreases the central symptoms produced by eating disorder, such as depression, anxiety, obsession, and compulsive character. However, due to the negative effects of the drug (mechanism of action, side effects, etc.) this medicine is not useful in malnourished patients.

Heat, new therapy?

It is logical to think that using the sauna helps reduce the body weight of people with anorexia nervosa. On the contrary, it seems that the sauna prevents the development of the pathology and improves the condition of the patient. This improvement may mean that people with anorexia do not use the sauna and that this activity is not considered a risk factor for this disease. On the other hand, due to the preventive character of the sauna, those who tend to anorexia would not fully develop the disease if they used the sauna.

Heat treatment was initially used to help control hyperactivity, as symptoms of hyperactivity are common in patients with anorexia nervosa. These patients cannot avoid being active and move at all times without any specific objective. Many times they perform excessive physical activity, work without measures, do not rest and that satisfies them very much. In addition, some studies have shown that reducing food intake is evident if there is excessive activity or physical exercise.

Excessive exercise in anorexia nervosa has always been considered to be a behavior caused by patients' desire to lose weight. But this idea is being discarded and, instead, a psychobiological approach is being imposed that considers hyperactivity as a central symptom of the disease. The hypothesis that is currently being imposed is that the excess activity of anorexia nervosa is not the intentional strategy of burning calories, but the behavior derived from the alteration of thermoregulatory homeostasis derived from food restriction. In addition, hyperactivity, due to food inhibition, acts as a maintenance factor in anorexia nervosa according to this hypothesis.

For the study of anorexia nervosa have developed many animal models, but at the moment none of them has been entirely suitable. However, among these animals stands out the model called ABA, Activity-Based Anorexia. In this model, animals suffer a special procedure, they are reduced feeding time, that is, animals only have an hour and a half a day to eat. During this time they can eat everything they want. In addition, they are given complete freedom to access a wheel of activity. In this way, the animal, due to the stress generated by the reduction of food, develops a pattern of hyperactivity behavior (running on a wheel continuously). The symptoms of animals undergoing the ABA procedure are similar to those of patients with anorexia nervosa such as hyperactivity, hypothermia, intentional food reduction and weight loss. Therefore, it is proposed that the ABA model be an optional model for human anorexia nervosa. Therefore, it is used to investigate possible alterations in anorexia.

As mentioned above, appetite is the sensation that occurs in the hypothalamus and its regulation is a complex process that depends on many compounds. In this process we must take into account two types of systems: orexigens, or food generators, and anorexigens, or those that reduce appetite. They all influence the hypothalamus and their interactions cause hunger and satiety. Changes in these systems can cause anorexia nervosa. Therefore, the research groups led by Dr. Gutiérrez of the University of Santiago de Compostela and Dr. Echevarría of the University of the Basque Country (2009) investigated in the animal model ABA one of the main systems of hypothalamus anorexigeno, the system of melanocortines. In fact, melanocortinas not only affect appetite regulation, but also behavior and thermal regulation. When comparing the animal model ABA with a control animal, it was observed that the animals ABA suffered a hyperactivity of the system of melanocortinas, which could be the cause of the decrease of appetite, hyperactivity and, therefore, the decrease of the body weight of the animals.

Interest in the potential benefits of heat in anorexia nervosa is based on the influence of ambient temperature on the animal model ABA. Animals in a state of exhaustion lose the ability to digest food and it seems that this effect returns with heat therapy. Therefore, a high ambient temperature can prevent or delay the development of self-exhaustion of rats subjected to the ABA procedure. On the other hand, the heat caused a reduction in the melanocortinas system in ABA animals. At least partially, this reduction may be due to the heat action mechanism. Heated animals recovered appetite and body weight and increased activity rates. It should also be noted that in rats without food restriction, that is, in controls, when increasing the temperature there was no special effect on activity, food behavior.

The next step would be to check whether effective heat treatment in animals is also effective in humans. It may be thought that patients would avoid heat by gaining weight. However, surprisingly, many patients look for heat: they heat themselves, drinking hot drinks, putting them near the heaters or covering them with blankets.

In a study, Gutierrez, along with researchers from Canada and Australia, applied heat to certain anorexies that characterized hyperactivity (2004). He used three strategies: continuous exposure of ambient heat, use of thermal vests and sauna baths in the infrared cabin. The results were better than expected and in the three cases analyzed the same pattern was observed, the immediate reduction of hyperactivity from the beginning of treatment and the progressive formation of patients. It seems, therefore, that heat treatment has its own benefits, regardless of the strategy used. It is significant that with the improvement of hyperactivity patients did not express anxiety or depression; that sleep, constipation and other body functions improved and that the obsessive count of kilocalories, fear of thickening and distorted perception of body shape decreased. Gutierrez, in another trial, analyzed the effectiveness of heat treatment through thermal vests to gain weight in sick nerve anorexies admitted under mandatory feedback regime. The results found no differences in weight gain between those who received heat and those who did not, but patients perceived an improvement in other symptoms such as better digestion and stress reduction.