It is established that the efficiency of thermoregulatory mechanisms of the body is considerably high: the extreme cooling of patients (1 to 3 minute exposure to the air with the temperature down to -120°C or forced air cooling of separate areas of the body with the temperatures down to -180°C for several minutes) provokes a chain of defense reactions, but at the same time no overstrain of thermoregulatory mechanisms is registered.
It is stated that the defense physiological reaction to dosed general cooling is very favorable for the patients with rheumatic disorders, because it relieves pain and the muscle spasms. Besides, the response is manifested through vegetative-vascular changes, due to activation of the adrenal system. At the same time, other authors, who used exposure to extreme temperatures (down to -120°C in cryo-cabins) for treatment of the patients suffering from chronic rheumatic arthritis did not register the difference in the adrenal function stimulation between the patients and the control group of healthy people, because release of cortisol and 17-oxicorticosteroids (17-OCS) by this gland during the process of cryotherapy did not display considerable alteration.
According to dr. R. Fricke (1989), the favorable effect of ACT for treatment of motor apparatus disorders (the patients have stayed in cryo-cabins with the temperature of -160°C for 1 and 3 minutes) is called forth by stimulating the functioning of anterior lobe of hypophysis. He found out, that under the influence of ACT procedure, the level of cortisol in blood serum of the patients was decreased, the level of prolactin and somatotropic hormone remained unchanged, the content of noradrenalin increased and that of adrenalin was within normal limits. Recently some investigators tend to explain the ACT influences by contribution of the neuropeptide system and formation of endogenous morphinoid substances. This phenomenon was confirmed by data obtained by monitoring the patients with pain syndromes of the vertebral column, receiving cryoapplications with the temperature -140°C and the patients with bronchial cryospasm, treated by cooled air (for desensibilization).
While studying the cardiovascular system reaction for cooling, it was established that general aircryotherapy does not cause excessive blood circulation strain; that is why it can be used for patients with ischemic heart disease in the initial stage. When monitoring such patients in cryo-cabins (with the temperature about -110°C, staying in the cabin up to 3 minutes) and after the procedure, no provocation of myocardial ischemia and no cardiac rate disturbances were registered. The patients with normal arterial pressure (AP) under the influence of general ACT showed the increase by no more than 10 mm of Hg, though in case of hypertension the increase may also be higher.
Presently it is believed that the vessels constriction under the influence of cold is the first defense reaction of the body for cooling, the second defense reaction is luminal expansion of the blood vessels observed in different time (from 1 to 3 hours) depending on cooling dosage. The intensity of cold impact definitely has effect on the degree of consequent skin reddening (reactive hyperemia), however no linear dependence has been registered. It is believed that the first defense reaction is aimed at heat preservation, the second one provides intense heat buildup At the same time dividing the vessels response into first and second category is rather relative.
The real situation is characterized by rhythmical oscillations of contraction and expansion of vessels in the skin, which thus prevents ischemic damage of tissues. It must be stressed, that the optimum effect of ACT may be achieved with skin cooling to the temperature of 8°C - 15°C.
The initial body response to cryotherapy is related, first of all, to stimulation of skin receptors. Long cooling causes their inhibition and partial paralysis, which is related to the patient's subjective feelings: first he feels cold, then burning and pricking, then pain, which gives place to anesthesia and analgesia.
The aptitude to regulate the muscle tone is one of the most valuable properties of ACT. Majority of authors use cold in order to reduce muscle spasm, others, viceversa, to enhance muscle tone. The latter achieve their goal through brief exposure to moderately low temperature (about 0°C). This results in increasing muscle strength and endurance.
Reducing muscle spasm is of great practical importance. The muscle relaxation is registered after a long (more than 10 min) cooling within the temperature range around 0°C or after a short-time ,but intensive exposure, to cold (up to -180°C).
The researchers proved that cold therapy with ice pack, as well as 2-3-minute exposure to cold air (down to -180°C) or staying in a cryo-cabin (about -110°C ) do not change muscles temperature and the temperature of nerve trunks. The ACT spasmolytic effects are brought about through the exteroceptive system of the skin and gammamotoneuronic system.
The recuperative (sanogenetic) mechanisms of cryotherapy are based on anesthetic, antiphlogistic and spasmolytic effects.
Therapeutic efficiency of general ACT (staying in a cryo-cabin with the temperature about - 110°C for 0.5-3 minutes) for the patients with rheumatic disorders of articulations is shown not only in reducing pain, but also in reliable improvement of articulation functioning and general improvement of the state of health. Besides, it was determined, that the same effects occur to the covered parts of body as well, for example, articulations of hands and feet protected with gloves and shoes.
Considerable improvement of patient's functional state is registered within several hours after the procedure.
The cooling of tissues affected by burns with liquid nitrogen vapors having the temperature - 100°C prevents secondary processes of deepening for the thermal injury.
Cryotherapy is efficiently used in a neurogeriatric clinics (for treatment of nervous system diseases of the aged people). Practically, there are no age limits for ACT with super-low temperatures established; the exposure to the cold air with the temperature down to -180°C was used for the patients up to 81 years old. It has been observed that ACT increases physical endurance of the patients by 6.8%, according to the data of bicycle exercise.
It should be stressed that the anesthetic effect, decreasing the need for analgesics, muscle relaxation, anti-inflammatory medication, the absence of side effects and age limitations for most methods make cryotherapy an important means of rehabilitation for chronic pain syndromes, in particular, those of neurological and rheumatic character.
The attention paid to this problem is determined by a clinic's requirement for complex rehabilitation methods, which give excellent results, as shown by recent investigations.
Exposure to cold simultaneously with or after some other physical agents (ultrasound, therapy with oxygen under high pressure - hyperbaric oxygenation, microwave irradiation and laser emission, ultraviolet blood irradiation) under experimental and clinical conditions demonstrated the possibility to enhance or reduce the action of a chosen factor by way of cooling. In order to enhance treatment efficiency the electric therapy is used together with ACT, in sequence.
Recently the devices and methods for simultaneous cold influence with direct or pulse (diadynamic, interference) currents are developed. Besides, there are separate cases of using ACT with alternating magnetic field. It is often recommended to combine the ACT procedures with physical exercises. Many researchers mention positive and considerable effect of the ACT procedures applied before physical exercises for the patients with rheumatic disorders.
For this category of patients discontinued treatment method is suggested. It consists in the exposure to cold for 3 min. with a 5 minute complex of therapeutic exercises, which are alternated consequently several times. The efficiency of combining the ACT with isometric exercises was shown as well, causing so called postisometric muscle relaxation. It is recommended to combine local exposure to cold air, for example, for an articulation, with bending and unbending, in this case, during all the procedure.
The patients with autonomic neuropathy underwent intensive movement therapy each time after cold immersions. This was aimed at achieving compensation of heat emission. After medical arthroscopy of the knee joint an ice pack for 15-20 min is used to decrease edema.
The basic medical efficiency of cryotherapy is related to stress stimulating influence upon hypothalamic-hypophysial-adrenal system, and with stimulation of the peripheral blood circulation as well. The total cryotherapy shows maximal medical efficiency. The treatment efficiency is determined not only by maximum air temperature level, but also by the rate of temperature descent. The duration of general cryotherapeutic modality makes 30-180 sec. During the cryotherapeutic procedure the patient's skin temperature goes down instantly to 0°C, but then due to the intensification of peripheral blood circulation, goes up to 35°C (the normal skin temperature is 32.5°C). The compensatory temperature rise lasts within one hour and a half. Together with compensatory temperature rise, during the cryotherapeutical modality the pain sense and constraint in articulation affected by rheumatic polyarthritis are suppressed.
The possibility of pain suppression in joints combined with overcoming of constraint makes easier the performance of curative gymnastics, which together with diet provides good results in rheumatic polyarthritis treatment. The analgesic influence of cryotherapy is considered to be a result of decreased activity of inflammatory mediators. That is why cryotherapy is prescribed for all types of polyarthritis: acute and chronic, infectious and non-infectious.
Other ways of general cryotherapy application are possible as well, for example, for the treatment of immunodeficiency and in order to increase nonspecific resistance of the body, or when treating burn wounds. Taking into consideration the comfort and velocity, the hardening effect of cryotherapeutical procedures allows using this technique in mass as a powerful preventive method, which is very easily arranged to be used both on an outpatient and on an inpatient basis (for instance, in preventoriums of large enterprises).
The modality of this cold therapy method was first based on practice of known and studied cold application procedures used for rheumatic disorders of articulations. However, quite soon, this method became core in comprehensive treatment of a variety of most severe diseases, which were very difficult or almost impossible to cure before. In the eyes of foreign experts, the application fields of extreme cryotherapy, which can be used as a valuable component of multimodal therapy, include the following: treatment of inflammatory articulation diseases, degenerative articulation diseases with secondary inflammation component, vertebral column disorders, inflammatory and degenerative, inflammations of soft tissues, collagen disorder, autoimmune diseases etc.
Japanese program of children hardening in extreme cryo-cabins proved to be quite efficient, as there was registered considerable decrease of the incidence for catarrhal infections in children after 10 sessions of general cryo procedure compared to the control group. Besides, the results of general extreme cryotherapy method for the treatment of bronchial asthma, chronic lung diseases, pollinosis proved to be quite satisfactory. The most valuable experience in general cryotherapy application is accumulated for treatment of depressive state, elimination of stress syndrome, drug addiction therapy, usage as a stimulator which amplifies functional abilities of the body. It is quite impossible to enumerate all the nosologic forms, therapeutic efficiency of which makes more than 85%. They include psoriasis, atonic syndrome, disseminated sclerosis, rheumatic polyarthritis . Based on the above facts this technique may be considered one of most remarkable achievements of the 20th century.