Living with the Weather

Shift from Bacteriologic to Physiologic Interest in Medicine 

When bacteriology supplied the cause of infectious diseases it gave definite direction to the development of medicine, both preventive and curative, for several decades. By learning the cause and the method of transmission, preventive measures were instituted more or less simultaneously throughout the world. The effects of these were shown everywhere by a reduction in morbidity and mortality. As a result, in the United States the general death rate dropped from about 18 per 1,000 of the population 50 years ago, to about 11 today. Since most of the preventive measures have been particularly operative in case of diseases which affect the young, those who formerly would have died during the first two or three decades of life now live on to mature years or even old age. 

Whereas 50 years ago about 95 per cent of illness was acute, today 75 per cent of it is chronic. This shift in the nature of illness has changed medical thought and practice; and physicians are now devoting more of their study to problems of development, the chronic infections, degenerative and deficiency diseases, and to disturbances of a functional nature. 

The change in type of disease calls for a more intensive study of the patient; and physiology now becomes of greater importance than bacteriology in providing an understanding of present-day medical problems. As physiologic knowledge increases, its contribution to the understanding of all diseases becomes more and more important. Even defense against infections is a physiologic process; and the scientific treatment of all diseases follows physiologic principles. 

In our study of man as a physiologic being we are impressed with the fact that he is influenced by many stimuli of both a physical and psychic nature. They may originate either outside the body or within. Internal stimuli may be set free by such processes as the digestion of food within the gastrointestinal tract; by parenteral digestion of proteins; by secretions of various kinds; by bacterial toxins, or other toxic substances which arise within the body; or, by stimuli of emotional origin. Stimuli which arise in the external environment are also of many types. Among those which most frequently cause helpful stimulation, on the one hand, or stresses and strains which unbalance the physiologic mechanism, on the other hand, are the atmospheric forces in the midst of which we live, but to which we fail to assign a position of importance.

 

Man’s Physiologic Adaptation to Meteorologic Forces 

The human body is a receptor mechanism which receives and transforms stimuli of various kinds and varied intensity into action. It has a remarkable power of adaptation. One who is physiologically stable has the ability to adjust to heat equal to that in the tropics and to cold equal to that in the Arctic; to an atmosphere saturated or one almost devoid of moisture; to a gentle zephyr or to a wind movement of hurricane proportions; to a low or high barometric pressure; to light of great or of little intensity; and to varying degrees of electric potential. 

Atmospheric forces are rhythmic in nature, varying daily, seasonally, and cyclically. They also vary geographically. The forces may be mild or turbulent. The varying reactions with which man responds may depend on constitutional or acquired differences. He varies in reaction in illness and in health, and at different age periods. He may possess organs with varying susceptibility. Some men might be particularly subject to diseases of the respiratory tract; others to diseases of the cardiovascular, renal, gastrointestinal, endocrine or blood systems. From this it can be seen that there are many variables which will determine or modify the manner in which man’s physiologic mechanism will react to the atmospheric forces; and it is evident that he does not adapt so readily or so completely when ill as when well.

There is a difference in opinion as to what particular atmospheric force is most potent in causing changes in the body’s reaction. It may be, as far as present knowledge is able to determine, some one or some combination of several forces. The action of any force which produces stimulation is shown in changes in oxidation. This may be confined locally or expressed widely. The stress falls heaviest upon tissues which are the seat of pathologic change because the cells which are involved have altered reactivity. A hyperactive cell has its electric reactivity altered and its permeability increased. So, strong stimuli may produce effects which are purely physiologic, or effects which fall outside of normal physiologic limits and result in dysfunction or disease. If disease is already present in a quiescent state, they may reactivate it. They may increase activity if the process is already active, or they may even cause death of the patient. 

The usual effects of atmospheric forces of normal intensity impinging upon the body of the average man in health fall within the point of normal physiologic stimulation. However, at times of storm the stress is multiplied many times and may produce harmful effects. Thus we live and enjoy, become ill, improve or fail to improve and die with the weather. 

If we attempt to explain how these effects are produced, we will find difficulty in establishing the cause with absolute definiteness. However, careful observation of groups of people will make it possible for the observer to satisfy himself beyond doubt that people in general are meteorologically influenced in their reactions, and that different individuals react with different degrees of intensity to the same stimulus. 

 

Physiologic Effects of Different Meteorologic Forces 

Some of the earliest studies in this country were those of Huntington.¹ He stressed the effects of temperature and humidity. He made a study of the daily work of three or four thousand mill operatives in New England, and the Southern States, also of 1740 students at Annapolis and West Point. He found that the daily variation of temperature in which the mean maximum was about 64° F. and the mean minimum was about 38° F. was the most favorable for productive effort. Of course, humidity, wind movement and other forces are modifying factors. Another important factor was the changeableness from day to day. He found that neither too great changes nor monotony were favorable for best physical or mental accomplishment, but that moderate variability added to climatic efficiency. He called attention to the fact that in the past, atmospheric features similar to those which he described as optimal were present at the time that many nations reached the pinnacle of their civilization. 

Petersen,² in his epoch-making observations, has studied the effects of the various meteorologic forces upon the many physiologic reactions of normal men with different constitutional peculiarities, as well as those suffering from different diseases. 

Likewise he has endeavored to determine the force which affects man most and stresses particularly barometric change which is most marked at times of storm. 

Mills^3,4 has studied the demands made by daily variations in temperature on people living in different climates. He has particularly noted the effects according to the manner in which they depart from the optimum temperature variation established by Huntington. This he illustrates by the following charts. In each figure the stippled band represents Huntington’s optimum daily variation.

Figure 1 represents a climate in which the diurnal variation in temperature for most of the year falls within this optimum, hence is a climate which favors productive effort throughout the year. Figure 2 is one in which both daily and seasonal variations show wide swings calling upon the individual to make enormous daily and seasonal compensation. Such a climate is rigorous and calls for adaptation which the less vigorous may not be able to make, Figure 3 is a monotonous climate such as is found in the tropics where the temperatures, both daily and seasonal, fall outside and above the optimal limits. 

Fig. 1. Daily maximum and minimum temperatures, Sucre, Bolivia, 1923 (Mills).

Fig. 2. Daily maximum and minimum temperatures, Bismarck, North Dakota, 1925 (Mills).

Fig. 3. Daily maximum and minimum temperatures, Georgetown, British Guiana, 1923 (Mills). 

 

Under conditions of optimal temperature man is able to accomplish most, and is best able to maintain health. The temperature with great daily and seasonal variations makes extraordinary demands upon man’s adaptive mechanism, and may precipitate disease in those with low resistance. On the other hand, it stimulates the strong to withstand unusual effort and raises their resistance to disease. Those who live in monotonous non-stimulating climates do not suffer from diseases which are produced by stress, such as hypertension, hyperthyroidism and diabetes, to the same extent as those who live in more rigorous climates.

That the prevailing diseases from which people suffer in these various climates would differ is to be expected. So is it reasonable that the same disease might affect people of these varying climates differently. It is well known that the people of the tropics do not show the same resistance to tuberculosis that is shown by those who live in the temperate zone, also that the less resistant patients do not withstand the rigors of Northern winters as well as those who are more vigorous. 

Appendicitis is more common in the more stormy portions of the United States than in the warmer, milder portions, but the mortality is greater in the latter probably because of the lack of the invigorating meteorologic forces which increase the patient’s ability to withstand. 

The rigors of the North increase the incidence of such metabolic disorders as thyroid disease, diabetes and pernicious anemia, as shown by Petersen and Mills. 

 

Storms

All atmospheric forces are more turbulent at time of storms, and physiologic mechanisms are called upon to make greater compensation. Storms, in the meaning here used, denote the condition in which the air, warmed in the tropics, is sent Northward producing a high pressure area which meets the cold air from the Arctic regions coursing Southward, thereby producing a low pressure area. The struggle between these air masses is productive of a turbulence which is designated as a storm. The barometric pressure changes; temperature and humidity are altered; air currents vary, and electric potential shifts. 

The major factors which determine the direction and course of these air masses are the masses of water and land, and the contour of the land, as modified by mountains, river valleys and plains. These being fixed and definite, the storm tracks are accordingly quite definite. The paths for the storms on the American continent descend from the North Pacific through the Mackenzie Basin or from Alberta and enter the Northwestern part of the United States, then they course Southward along the Eastern slope of the Rockies until they are deflected Eastward and Northward to pass over the Great Lake region and down the St. Lawrence Valley. Many of them pass farther Southward over the Mississippi Valley, but the main tracks keep well to the North. The Great Lake region has the reputation of being the stormiest area in the world. Northern Europe, on account of the land and water topography, escapes much of the storminess which dominates the Northern part of the United States. Excessive storminess is accountable for the rigorous, variable climate in the Northern portion of the United States, and calls for a hardy people. 

If one would comprehend the possible sum total of effects produced on man by atmospheric forces, he must consider both the daily and cyclical changes which occur in air masses; and that all differences in temperature, humidity, velocity, changes in ionization and electric potential, and differences in light transmissibility require adjustment. Think of the adaptation that is required of man to adjust to air movement when it attains a velocity of cyclone proportions, or of the rapid changes in barometric pressure at the time of tropical storms! 

 

How Atmospheric Forces Produce Effects

These atmospheric forces produce their effects through all of the physiologic mechanisms of the body, nerves, hormones and body electrolytes. They act primarily upon the skin with its rich supply of sensory nerves. These transfer the stimuli centralward where they are transferred to motor mechanisms, usually of the vegetative system, to be distributed to the various parts of the body for action. Some of these forces, too, produce psychic effects which may result in either normal or pathologic stimulation of the physiologic mechanisms. 

The fact that the stimuli act upon all of the physiologic mechanisms is illustrated by the effects of heat stroke in which the loss of sodium, the deficiency of the adrenals, and reduced sympathetic stimulation each make up a part of the picture. 

Meteorologic forces may bring about general physiologic response or a response limited to some particular organ. The latter may be the case when the organ is the seat of disease which prevents full and free physiologic adaptation. 

There is nothing specific in these meteorologic forces. They produce effects similar to those caused by other stimuli which produce general physiologic effects. This may be illustrated by pulmonary and pleural pain. Patients who have had pulmonary tuberculosis with involvement of the pleura may, long after the disease ceases to be active, suffer from pains in those sensory nerves which were reflexly influenced at the time of the acuteness of the process. Such pain is frequently brought on at the time of storms. However, it may come with other forces which act widely upon the physiologic mechanism such as emotional stress, infections, tiring, and menstruation. The same is true of other types of visceral pain. It has long been recognized that the arthritic is sensitive to weather change. 

These general physiologic stimuli are by no means always harmful. Mild meteorologic effects produce normal body activity and aid in restoring health when damaged. This is shown in the effects of favorable climatic influences and pleasing emotions upon people. 

 

Effect of Meteorologic Forces on Disease 

Ill effects, too, may be shown in observing the clinical course of a disease, such as tuberculosis. Hemoptysis, pain, insomnia, pleural effusion, metastatic spread, and exacerbations appear seasonally; and also appear in multiples at the same season, being precipitated by storms. The season which shows most exacerbations and most spread of the disease is the late winter and early spring, after the patient has been long subjected to the stresses of winter weather. A period of lesser severity is shown in the fall at the approach of winter. There is five or six times as much acute miliary tuberculosis in the spring as there is in midsummer. The same is true of tuberculous meningitis among children. This is shown in figure 4, from Engel and von Pirquet. 

Fig. 4. The relative percentage of cases of tuberculous meningitis in children for the different months of the year, showing the enormous increase in the spring months and low percentage in summer (Engel and Pirquet: Handbuch der Kindertuberkulose, 1930, i, 531).

 

For many years we have observed that there is a seasonal increase in the number of severe cases of tuberculosis at the end of winter and early spring. Moreover, we have noticed that storms hasten death in patients who are quite ill. 

Figure 5, from the 1937 Health Report for the City of Sheffield, England, shows numerous curves, but I wish to call particular attention to the atmospheric temperature curve; the death rate from all diseases, that from heart disease, and tuberculosis and other respiratory infections. It will be noted that the preponderant number of deaths occur in the colder months. These are not only the months of storm, but the months in which the effects of storms are cumulative, so that after a succession of severe stimulations the patient’s resistance is lowered and easily overcome. The death rates in many of our large Northern cities have been analyzed by Huntington, Petersen and Mills, and show the same increase in the cold and stormy winter and spring months. 

Fig. 5. The relation of mortality curves to temperature and seasons (Annual Report on the Health of the City of Sheffield for 1936).

 

Figure 6 shows the temperature chart of five patients who were in the sanatorium at Monrovia during April and May of 1938. Their temperatures are plotted against the barometric, temperature and humidity records of the period. It will be noted that on April 22 and 23 the temperature and humidity increased, preceding a slight drop in the barometer, and that four of the patients show slight clinical disturbance. The most marked atmospheric changes came on May 4 and 5, when there was a drop in the barometer, and elevation of temperature and a continuation of a high humidity which was preceded by a rain on the first and second of the month. 

Fig. 6. Relation of symptoms and complications in tuberculous patients to meteorologic factors.

 

It will be noted that patient 10419 showed the beginning of an active tuberculous process which lasted two weeks. Patient 10838 was suffering from a complicating pleurisy with effusion. The temperature had attained a maximum and was receding, but showed the beginning of a second elevation on the fourth. Patient 10774 had been free from temperature or complications for months and developed a pleurisy with effusion which began on the fourth. Patient 10857 was a psychoneurotic who was recovering from a streptococcal infection. Note the sensitiveness to meteorologic forces as shown in the temperature elevation on the same day as the others. Patient 10817 showed a smaller elevation of temperature on the fourth than she did on the 21 and 22 of April, but it was accompanied by a mild activity in her pulmonary lesion. 

In observing many patients over the past 35 years, we have noted that exacerbations of the tuberculosis and complicating lesions, such as pleurisy and hemoptysis, are atmospherically conditioned and are especially connected with storms. 

Nor is the seasonal influence confined to human beings and their diseases. Brown⁵ reports that there is an increase in the incidence and in the metastatic rate shown by mice infected with syphilis and with experimental malignancy in the late winter and early spring, and further that this harmonizes with the seasonal variation in organ size and weight.

Just what force or forces are responsible for these effects is not clear. In Southern California, where changes in barometric pressure are slight, we note the same phenomena that are noted in more rigorous climates where the fluctuations are greater. It may not be the barometric pressure or the changes in temperature which are responsible, but a combination of several or all atmospheric forces. In this connection a most interesting observation is reported by the Russian physicians who are studying man’s reaction to the weather in connection with the attempt to plant colonies in the Arctic regions. They have found that two or three days before the approach of a violent Arctic winter storm the contractions of the heart decrease, sometimes to about half the normal number per minute, and that the output per contraction increases in proportion. Moreover, this occurs two or three days before any meteorologic instruments register any warning of approaching change. 

Body chemistry, endocrine function and the sensitivity of the components of the vegetative system all show seasonal adaptations. In the winter the tissues are more active, cells more permeable, and the potassium is more prominent than calcium. In the summer the reverse is true. It readily can be understood that there should be a difference in the incidence of those diseases which are seasonally conditioned. It can also be surmised that there would be a difference in diseases which are conditioned by atmospheric forces. 

Man is a constitutional and developmental variable, possessed of individual powers of reaction under conditions of both health and disease. He lives in an atmosphere disturbed by many forces, which are subject to diurnal, seasonal and cyclical changes. These various forces react upon his physiologic mechanism and cause many changes in its efficiency, sometimes calling out favorable response, again producing harmful effects. These reactions may result in well-being and conditions of health; in conditions of malfunction and disease; and eventually in healing with restoration to health; or in death. 

Man lives happily, he becomes ill, and recovers or dies with the weather.

 

References Cited:

1. Huntington, Ellsworth: Civilization and Climate, 1st ed. 1915, 3d ed. 1924, Yale University Press, New Haven, Conn.
2. Petersen, Wm. F.: The Patient and the Weather, 4 volumes, 1934-38, Edward Brothers, Ann Arbor, Michigan.
3. Mills, C. A.: “Health and disease as influenced by climatic environment,” Internat. Clin., J. B. Lippincott Company, 1936, Vol. II, Series 48.
4. Mills, C. A.: “Climatic stimulation in relation to resistance, to infection and general metabolic level,” Trans. Am. Clin. and Climat. Assoc., 1934.
5. Brown, Wade H.: “Constitutional variation and susceptibility to disease,” Harvey Lectures, 1928-29, p. 106, Williams and Wilkins, Baltimore.