Sauna may provide some relief to patients with asthma and chronic bronchitis, and may also alleviate pain and improve joint mobility in patients with rheumatic disease. The sauna does not cause drying of the skin, and may even benefit patients with psoriasis, although sweating may increase itching in patients with atopic dermatitis.

Contraindications to sauna include unstable angina pectoris, recent myocardial infarction, and severe aortic stenosis. Sauna is safe, however, for most people with stable coronary heart disease.It is not harmful to the aged or even young infants over 3 months in moderation and does not affect wound healing. Sauna use may reduce the incidence of the common cold, and temporarily relieve the symptoms. It increases performance in endurance sport, increases plasma volume and red cell volume in athletes, decreased systolic blood pressure, significantly improved exercise tolerance, increased peak respiratory oxygen uptake, and enhanced anaerobic threshold in chronic conditions.

Sauna plus multidisciplinary treatment may reduce chronic pain more effectively than multidisciplinary treatment alone. Sauna reduces chronic pain more effectively than cognitive behaviour therapy. It is indicated for rheumatic pain (with cold shower) but not for neuropathic pain. Is effective for appetite loss and mild depression. Indicated in reducing symptoms in Chronic Fatigue Syndrome, and rheumatoid arthritis, and indicated for anorexia nervosa. Sauna improves function in conditions such as, congestive heart failure, and high blood pressure, improves vasodilation, improves heart arrhythmia, and reduces heart rate on exercise. Sauna has been proposed for treatment of other conditions such as, glaucoma, Sjogren syndrome,chronic fatigue syndrome, fibromyalgia, anorexia nervosa, obstructive lung disease,recuperation after childbirth, and also for lifestyle related diseases of, diabetes, arteriosclerosis, obesity, hypertension, hyperlipidemia, atherosclerosis and smoking induced symptoms.

Sauna has also been found to reduce levels of stress hormones adrenalin and noradrenalin and to increase levels of beta endorphin. However it also causes a substantial rise in the stress hormones ACTH (adrenocorticotropic hormone), and cortisol due to hyperthermic stress on the body. Cortisol remains high even after 30 minutes of rest.. Sauna also found to reduce prostaglandin F2alpha and protect against oxidative stress. It enhances activation of monocytes to bacteria and endotoxins.

Other benefits of saunas: It has shown that regular saunas combined with exercise therapy can efficiently clear organic chemicals, solvents, drugs, pharmaceuticals even PCBs and heavy metals from the body.

In addition a sauna followed by a cold shower has been shown to reduce pain in rheumatoid arthritis where pain is mediated by sensitised c-fibre sympathetics. Regular saunas have also been found to improve micro circulation reduce vasoconstriction and hypertension. Many symptoms of chronic illnesses may be due to vasoconstriction effects eg. cold sensitivity, pain even mood states, and sauna improves microcirculation and blood supply to constricted areas. Research has also shown that adaptation to cold through short term cold stimulus, as in cold swimming, immersion (or showers) has the added benefit of improving the body's anti oxidant capabilities, with increases in glutathione and reduction of uric acid, which may mean better handling of the stresses of illness.Those that are shown to involve reduced glutathione or increased glutathione use, include; cardiovascular conditions, pulmonary diseases, diabetes, inflammatory bowel diseases, cancer, osteoporosis, aging, and after pesticide exposure. Conditions involving oxidative stress include neuro degenerative diseases, CFS, bone fracture and others. Conditions in which increased uric acid may be a risk factor include, gout, metabolic disease and vascular diseases.

A reported study from the Thrombosis Institute in London into the effects of the cold bathing found that volunteers that followed a disciplined daily regime had increased immune white blood cells and the level of the bodies natural blood thinning enzymes substantially increased, improving micro circulation. It also stimulated the production of hormones such as testosterone in men, and boosted women's production of estrogen. Cold water immersion raises thresholds of pain tolerance, and aids adaptation to cold, reduces muscle spasm, can influence the frequency of respiratory infections and improve subjective well-being. It may cause an immunological modulation in terms of the Th1-type pattern, which is a proinflammatory cytokine profile. It is involved in diseases such as arthritis, diabetes, inflammatory myopathies, inflammatory bowel disease, psoriasis, CFS, fibromyalgia, chronic pain, fatigue conditions, auto immune disease and other inflammatory conditions. Cold water adaptation reduced total cholesterol and LDL cholesterol, lowered plasma viscosity and blood pressure rate product. Cold water immersion reduces recovery time in athletes, enhances repeat performance and reduces exercise induced muscle damage.

Cold water exposure challenges both the neuro-endocrine and the immune systems, reduces stress hormones and attenuates their response. Increases ADH and cortisol and increases immunomodulatory cytokines. Cold water exposure and adaptation can modify the sensory functions of hypothalamic thermoregulatory centres to lower heat loss and produce less heat during cold exposure and have immunostimulating effects. The thermogenic action of adrenaline in cold exposure produces heat and may reduce this stress hormone. An important effect is the ability of sauna to use up excess sympathetic nerve tone in both the central and peripheral nervous systems and just as importantly use up excess levels of local tissue hormones involved in feedback loops to the hypothalamus, thus aiding recovery in chronic illness. The therapeutic sauna with hot cycle followed by a cold cycle brings the benefits of both, forces all the blood to flow gently and evenly outwards to the skin to cool off in the heat of the sauna, and then forces it to flow evenly inwards to protect and heat the vital organs of the body when suddenly cooled. With sauna, sections of the body with chronically deprived blood, increase supply and reduce oxidative stress. As the blood supply cycles into the organs and then out to the skin it acts like a pump bringing stored chemical toxins from remote areas of the body through the microcirculation to the skin to be removed in sweat.

The parasympathetic system governs sweat glands secretion and is increased by sauna. It has been shown with drugs such as caffeine, that delayed metabolic (organ) clearance was offset by a minor (2.5 percent) elimination in (skin) sweat by sauna. Sweat tests have shown pharmaceutical drugs are eliminated in sweat. Narcotics, alkaloids, and barbiturates are eliminated in sweat, and elimination increased with heat. The beneficial effects of therapeutic sauna are both temporary and long term, with some benefits lasting about 24 hours. Adaptation and detoxification will occur after longer use when the practice can be suspended or continued if beneficial.