Medical Climatology

a branch of medicine concerned with the effect of climatic and weather factors on man and with the ways in which these factors are used for therapeutic and prophylactic purposes. Medical climatology studies the physical and chemical nature of various natural stimuli and the character and mechanisms of the physiological reactions and pathological changes elicited by these stimuli in man when he is in his native climate and when he is exposed to unfamiliar climatic conditions. Medical climatology investigates such important matters as the geographic distribution of diseases and the influence of geographic factors on the development of human diseases.

Since ancient times people have been empirically collecting information on the effect of weather on human health. The works of Hippocrates (fifth and fourth centuries B.C.) contain a brief assessment of the effect of seasonal, weather, and various geographic factors on the course of diseases and on the general condition of human beings. Recommendations regarding the use of natural climatic factors in the treatment of certain diseases can be found in the works of A. Celsus (first century A.D.) and C. Galen (second century). Medical scientists of the Renaissance such as P. Paracelsus (16th century) and T. Sydenham (17th century) attached considerable significance to the role of natural factors in the origin and treatment of diseases. Advances in the natural sciences during the 18th and 19th centuries and the development of meteorology were important preconditions for discovering the interrelations between the organism and the environment, and they made possible a study of the organism’s reactions to climatic influences. The first attempts at treating certain diseases in marine, mountain, and desert climates were made in several countries at the end of the 18th century. Special studies on medical climatology appeared in the middle of the 19th century (for example, the works of the French scientist G. Lombard).

The Russian climatologist and meteorologist A. I. Voeikov made an important contribution to the development and growth of medical climatology as an independent discipline. Voeikov summarized the views on medical climatology that prevailed at the end of the 19th century in his Study of Climates for Purposes of Climatic Therapy and Hygiene (1893).

The Soviet school of physiology played a significant part in laying the theoretical foundations for medical climatology: L. A. Orbeli’s teaching on the adaptative-trophic importance of the adrenosympathetic nervous system, K. M. Bykov’s theory of cortical-visceral relations, and I. P. Razenkov’s studies on the mechanisms of thermoregulation and on the effect of atmospheric pressure on the organism. Hygienic studies on the adaptation of the organism to the environment and the setting of standards to improve work and living conditions were an important contribution to the development of medical climatology (V. A. Levitskii, A. A. Letavet, G. Kh. Shakhbazian). Interest in medical climatology in the USSR increased sharply in the 1920’s after the creation of an extensive network of sanatoriums and health resorts and an intensive migration of the population. Research on the use of the restorative powers of nature was started throughout the USSR. The development of new lands required a thorough investigation of local climatic conditions in order to improve these conditions and facilitate the acclimatization of man. The growth of medical climatology resulted in its becoming differentiated into independent scientific fields: climatophysiology, climatopathology, climatotherapy, and medical meteorology (the Soviet scientists A. D. Slonim, A. P. Avtsyn, and G. M. Danishevskii and the foreign investigators W. Mörikofer, D. Assman, R. Reiter, and O. Edholm).

Climate affects a living organism (the biotropic effect of climate) through individual factors (meteorological elements): temperature, air circulation and humidity, atmospheric pressure, cloudiness, intensity of solar radiation, and so forth. Each factor can by itself influence various functions of the human organism. (For example, the wind intensifies heat emission and makes breathing difficult by impairing the coordination of respiratory movements and their normal rhythm.) However, the individual functions of the body usually depend on a combination of several weather factors. For example, thermoregulation is affected by the temperature, humidity, rate of air movement, solar radiation, and other factors. The intensity of the biotropic effect is often due not so much to the absolute magnitude of the meteorological elements as to their time gradient—that is, the quicker a quantitative change in some factor occurs, the less time the organism has to adapt and the sharper its response. Therefore, climatophysiology is very interested in studying weather fronts, which cause abrupt changes in atmospheric pressure, air temperature, cloudiness, and precipitation as they pass through.

Climatic factors exert their influence on the body reflexly through the central nervous system and the neurohumoral system. Under natural conditions man is simultaneously exposed to the influence of many natural factors that in the aggregate make up the weather. Periods when different types of weather succeed one another are particularly hard to tolerate; the more contrasting and sharper the succession, the more pronounced the pathological meteorotropic reactions of the body.

Types of climate (marine, continental, mountain, desert, polar) are distinguished, and they too have a significant influence on the human organism. In some geographic zones (the arctic, the antarctic, deserts) the climate is so harsh as to be barely endured by man (extreme conditions) even when he uses modern means of life support. Besides the major climatic zones, cities, dwellings, industrial plants, and places used for cultural and other purposes have their own specific characteristics and also expose man to climatic and weather factors. Climatic factors also affect man’s health indirectly, for example, by influencing the survival rate and life cycle of the causative agents and transmitters of infectious and parasitic diseases.

In addition to investigating these meteorological elements, medical climatology is greatly concerned with the effect on the organism of other biologically active factors such as changes in the chemical composition of the air (for example, its content of ozone and nitric oxide), fluctuations in the amount of oxygen in the free atmosphere, aeroionization, solar activity, and changes in the earth’s magnetic and electric fields. The rapid growth of industry is related to the appearance in the atmosphere of anthropogenic factors, that is, factors caused by human activity (radioactive and other kinds of dust, aerosols, certain gases), which actively affect the living organism.

Regular periodic changes in environmental biotropic factors (daily, annual, and other fluctuations) alter the activity of many physiological functions of the organism as well as man’s work capacity. The pronounced seasonality of fluctuations in the frequency of many diseases and pathological reactions (for example, angina pectoris and hypertensive crises) is related to these changes. Study of bioclimatic shifts in various geographic zones was of value in working out climatoprophylactic measures (use of drugs, special regimen for patients) to prevent the development of seasonal diseases and the worsening of the course of diseases previously contracted under the influence of unfavorable climatic conditions.

In the USSR, medical climatology is studied in institutes of health-resort medicine and physical therapy and in various research institutes of clinical medicine and hygiene. The medical commissions of the Geographic Society of the USSR are also interested in the subject. The problems and progress of medical climatology are discussed in the journal Voprosy kurortologii, fizioterapii i lechebnoi fizicheskoi kul’tury (Problems of Health-resort Medicine, Physical Therapy, and Exercise Therapy; since 1955) and in other medical and geographic journals.

Research institutes and scientific societies of bioclimatology also exist in foreign countries: the institute associated with the meteorological and hydrological service in the German Democratic Republic, the society for promoting medical meteorological research in the Federal Republic of Germany, and institutes of balneology and climatology and the bioclimatic society in the Polish People’s Republic. Similar institutes are also to be found in many other countries. The International Bioclimatic Society was founded in 1956. The following are some of the journals and collections that deal with medical climatology: Medizinmeteorologische Hefte (Hamburg, since 1949), Wiadomości uzdrowiskowe (Poznań, since 1956), and Presse thermale et climatique (Paris, since 1920).