The sauna and pregnancy

Sauna bathing does not appear to affect fertility in men. Nor is the sauna teratogenic. The haemodynamic changes brought about by the sauna are similar in non-pregnant and pregnant women, regardless of the duration of pregnancy. There are, however, differences in the hormonal responses. Pregnant women adapt well to the thermal stress of the sauna, which is also true of the fetus, provided that it is healthy. Although the fetal heart rate rises during maternal hyperthermia, cardiotocographic tracings remain normal during and after maternal thermal stress. Healthy pregnant women may safely have sauna baths throughout their pregnancy.     

The sauna and children

In Finland sauna bathing by infants and children is guided by an empirically acquired parental understanding of the limits of safe heat "exposure". Finnish children are rarely allowed into a sauna alone before they are 7 years old. Finnish parents observe the post sauna bathing behaviour of their children, and this helps them to establish safe limits of exposure and avoid any adaptation problems. The after effects of sauna bathing of children reported in this study are substantial enough to warrant clinical paediatric involvement in unravelling the relation between the psychosomatic symptoms reported by children and their exposure to the raised temperature. There is also the need, even in Finland, of investigating the sauna bathing of children to establish objective criteria for promoting safe sauna bathing habits. Sauna bathing is a centuries old family tradition in Finland. There are 1.4 million saunas in a country with population of some 4.8 million people. Most families either have their own sauna or one close to where they live. In addition, Finnish children have access to sauna facilities at local sporting, recreation and swimming centres. Sauna bathing often takes place in connection with physical education (PE) lessons or sporting club activities for those over the age of 7 years. The average Finnish family takes a sauna bath once a week, and Finnish children are introduced to sauna bathing in early infancy. Although exposure to the raised temperatures normally encountered in a sauna can cause thermoregulatory imbalances in children there are no established guidelines for the safe use of saunas by infants and children.     

The sauna and sauna bathing habits--a psychoanalytic point of view

Sauna bathing is a pleasant and relaxing experience that combines psychic, physical and social pleasures. A person's inner feelings about sauna bathing, its essential components are mainly unconscious. The sauna bath reduces the aggressive behaviour and enables bathers to forget the commonplace pressures of everyday life. The sauna evokes memories of childhood development, awakening feelings of maternal warmth and paternal power in the bather. The sauna is a positive mental health resource, even though its effects are transitory.     

The sauna and rheumatic diseases

Although sauna bathing is a traditional means of treating rheumatism, its effects on rheumatic diseases have not been studied. Animal studies suggest that hyperthermia could have a favourable effect in cases of chronic rheumatic inflammation. More than fifty percent of patients find that sauna bathing alleviates rheumatic pain and improves joint mobility. The effect is similar in both inflammatory and non-inflammatory disorders. Nearly all men experience sauna bathing as helpful, whereas one-fourth of women find it detrimental. Rheumatic pain is exacerbated and joint mobility decreases on the day after a sauna. Exacerbation of pain is more obvious in non-inflammatory diseases, especially in fibromyalgia, than in inflammatory diseases, and more obvious in women than men. It can be prevented by proper cooling.     

The sauna and body fluid balance

Sauna bathing may affect the fluid, electrolyte and acid-base balance. In addition to sweating and thirst, a sauna bath also has effects on many endogenous regulatory mechanisms maintaining the balance between the fluid compartments and appropriate distribution of the circulating blood. Although the sauna-induced fluid loss is usually not very severe, its adequate replacement as early as possible is important. In practice, the most convenient and effective way is to replace the fluid loss by small liquid doses repeated frequently during the bathing. If a sauna bath is taken after heavy physical activity, the fluid compensation may be necessary already before bathing.     

The Finnish sauna and cardiovascular diseases

From time to time it has been claimed that the thermal stress caused by sauna bathing can be harmful to persons with cardiovascular disorders. Furthermore, elderly persons in general, who have experienced no symptoms from bathing, have also been cautioned. However, several studies carried out in Finland did not confirm the adverse effects of bathing on the elderly and cardiovascular patients. The controversial results obtained in Finnish and in some foreign studies are at least partly due to the different test conditions. The typical Finnish sauna bath is safe, and even patients who have recovered from acute myocardial infarction can enjoy the sauna without incurring any harmful cardiovascular effects.     

The sauna and bathing in different countries

Hot baths have been popular at different periods in different countries, although the sauna in Finland, has been popular for two thousand years. Bathing practices and the use of the sauna differ, though a common feature is inducing sweating followed by cooling off to create a sense of wellbeing. But in many places the sauna has been used to mask other practices, including those which pander to people's sexual appetites. It would be advantageous therefore for supporters and advocates of the sauna to try to correct the abuses.     

Lungs and ventilation in sauna

For over a hundred years Finnish sauna has been documented as a physiotherapeutic method in respiratory diseases. Physiological changes of ventilation remain small (about 10%) in the sauna. Heat load, sauna air and sympathetic stimulation generally do not cause problems to the lungs. Electron microscopic studies have not shown irreversible damages to the airway epithelium. Sauna takers should avoid bathing during acute respiratory infections. Sympathomimetic drugs may provoke tachycardia and arrhythmias in the sauna.     

Plasma catecholamines in Finnish sauna

Plasma catecholamines were measured by a modified single-isotope radioenzymic assay in five healthy medical students during and after a Finnish sauna bath with or without previous beta-blockade. The plasma noradrenaline rose more than twofold after 10 min in the hot room (100 degrees C) while the plasma adrenaline content exhibited smaller increases. The plasma noradrenaline concentration remained elevated or further increased after 5 min in a cool swimming pool (22 degrees C) whereas the exposure to cool water restored the plasma adrenaline concentration to resting values. Plasma noradrenaline, but not adrenaline, was still markedly elevated after a rest period of 15 min after the cool pool. Oxprenolol (40 mg) given 30 min before the sauna did not alter the plasma catecholamine pattern although it effectively lowered the heart rate before, during, and after the exposure to the heat stress.     

Regular sauna bathing and the incidence of common colds

The high morbidity of common colds means that their economic importance is considerable, with colds causing more loss of productivity than any other infection. As no effective prophylaxis is available, this trial was to test the hypothesis that sauna bathing can reduce the incidence of common colds. Twenty-five volunteers were submitted to sauna bathing, with 25 controls abstaining from this or comparable procedures. In both groups the frequency, duration and severity of common colds were recorded for six months. There were significantly fewer episodes of common cold in the sauna group. This was found particularly during the last three months of the study period when the incidence was roughly halved compared to controls. The mean duration and average severity of common colds did not differ significantly between the groups. It is concluded that regular sauna bathing probably reduces the incidence of common colds, but further studies are needed to prove this.     

How the sauna affects the endocrine system

The sauna induces changes in the secretion of hormones, some similar to changes induced in any other stress situation and others characteristic of exposure to the sauna. Noradrenaline is usually the only catecholamine raised by the sauna in people accustomed to it. The secretion of the antidiuretic hormone is increased and the renin-angiotensin-aldosterone system is activated. The concentrations of the growth hormone and prolactin, in particular, secreted from the anterior pituitary are increased in the circulation. The concentration of the immunoreactive beta-endorphin in blood may also increase which may reflect the feeling of pleasure or, on the other hand, discomfort induced by the sauna. The views on the effects of the sauna on the secretion of the ACTH and cortisol are partly contradictory, probably due to differing ways of taking the sauna bath. In Finnish sauna takers the concentration of cortisol in blood is not usually increased. The changes induced by the sauna in various hormone concentrations in the circulation are, however, normalized within a couple of hours after the heat stress.     

The shoulder in sports

Many sports activities that involve the upper extremity entail similar patterns of movement. Analysis of these activities, a better understanding of the throwing motion, and an awareness of shoulder diseases or injuries have led to a rational plan for investigation and management of shoulder problems. Evaluation often extends beyond the usual medical boundaries and must be based on information obtained from an analysis of sports mechanics, a review of training methods, and a physical examination directed at determination of flexibility, strength, endurance, and the presence of inflammation. Three common sports injuries are damage to the acromioclavicular joint (shoulder separation), instability of the glenohumeral joint, and a spectrum of pathologic changes in the rotator cuff. Sports that are commonly associated with shoulder problems include swimming, baseball, tennis, football, and gymnastics. Treatment may comprise rest, changes in training methods, an alteration of technique, and a physical rehabilitation program. Surgical treatment has a well-defined role, but it is usually optional.     

Traditional use of the sauna for hygiene and health in Finland

Finns have used the sauna for centuries to clean themselves, to maintain their health and even to help in treating a variety of ills. Up to this century the sauna was widely used as a place for childbirth. But the main reason for a sauna is the pleasure of sauna bathing and the craving for the feeling after the sauna. The longevity and effects of the sauna in Finland are linked to the view of the sauna as a holy place; participants have to behave in the sauna as they would in the church. The use of the vihta or vasta (a sauna whisk made of birch branches) has been an essential part of sauna bathing. Beating with the vihta promotes sweating and stimulates the warm skin. Many curative and magical effects have been attributed to the practice. Seldom has the sauna been thought to cause any disease.