Weather sensitivity is the vulnerability of an organism to atmospheric changes, by triggering or amplifying latent dysfunctions and illnesses. The causes of this situation stem from the modern lifestyle, particularly for those who live and work in major urban areas, where pollution, processed food, stress and a sedentary way of life favor the appearance of such sensitivities.
There are four types of weather sensitivity:
- The weather-adaptable type – those that easily accommodate such fluctuations.
- The weather-dependent type – those that experience these changes on a psychological level and their health impact manifests trough nervousness, headaches or depression
- The anticipatory type – those that can predict weather changes through various symptoms, such as painful scars.
- The weather-sensitive type – those whose illnesses are activated by changing weather, such as rheumatism.
The ambient and our health are linked to the climatic (and bioclimatic) comfort. The most important climatic elements that exert a significant influence over the human body are: temperature, moisture, precipitations, air movement, atmospheric pressure and solar radiation. Due to rapid changes over time and space, these factors are more aggressive and stressful in their impact on our physiology.
The human body perceives weather changes through its peripheral nervous system receptors (thermal, tactile and proprioceptive) located in the skin, eye, ears or respiratory system. The information is then passed on to the central nervous system, where it’s analyzed and used to control the endocrine system, the cerebral cortex and the overall nervous system. Each individual reacts differently, according to his or her age, adaptation, defense mechanisms and illness.
Temperature plays a major role in our body. Thermal homeostasis is defined as the ability of the organism to regulate its temperature between the limits of normal values, or, in the words of physiologist Walter B. Cannanon, “the body’s wisdom”. Thermal homeostasis is dictated by the hypothalamus, a small nervous center in the middle of the brain, weighing only 4 grams. The temperature can be altered through sweating or by influencing the blood vessels that carry blood to and from the skin.
A positive or negative change in temperature is first sensed by the skin (the peripheral nervous system), and depends on the amount of water retained by the body (human body cells contain up to 70% water). Temperature regulation requires a significant amount of energy.
Body surface, age, outside temperature and the activity of endocrine glands, all condition the basal metabolism rate which represents the normal heat output of the organism.
Depending on age, sudden temperature changes cause different reactions. For example, old-aged people and young children are less likely to tolerate extreme temperatures, because of their inadequate capacity to adapt to their environment. The impact of temperature changes is illustrated by the relation between temperature and mortality.
Very high temperatures cause the most victims around the world. Together with age and gender, elevated temperatures influence mortality and morbidity.
Under conditions of stress caused by high temperatures, the body increases the amount of water it eliminates, together with salts, which leads to physical exhaustion and extreme fatigue.
The loss of water through perspiration depends on the external temperature of the environment, humidity and wind.
Conduction is the transfer of heat from the human body towards an outer object having a lower temperature.
Convection is the replacement of warm and humid air near the skin by colder, drier air, and it accounts for around 15% of the total heat loss.
Radiation is responsible for 60% of the total heat loss experienced by the human body.
Diseases caused by elevated temperatures are often cardiovascular in nature (heart failure, strokes), and are triggered by an increase in the heart rate, dilation of blood vessels, a drop in blood pressure and even a state of collapse (very low blood pressure, tachycardia). Other circulatory problems may appear, accompanied by thermal shock, intestinal infections, heatstroke (which can cause a state of delirium and even memory loss), sunstroke and dehydration.
The stress caused by very low temperatures affects people with depressed immune systems, particularly old people, newborns, alcoholics and those that suffer from another underlying medical condition. Nevertheless, there are several factors that influence our ability to adapt to such conditions, such as nutrition, the layer of subcutaneous fat and even gender (for example, women have a higher body temperature than men).
In contact with cold air, the body insulates itself through the process of generating heat (by means of muscular contractions) and peripheral blood vessel constriction (which decreases the amount of blood going to the extremities). Also, a thicker layer of adipose tissue helps with insulation.
A significant drop in temperature can cause hypothermia, which produces serious problems in the body when its temperature falls below 35 degrees Celsius. Below 31 degrees, muscles become stiff and under 24 degrees, the heart ceases to function entirely. Low temperatures also cause cardiovascular problems, such as tachycardia (an abnormal increase in the heart rate), high blood pressure, the Raynaud Syndrome, chest pains (due to insufficient levels of oxygen in the heart’s muscles), frostbites, aggravated rheumatism and various viral respiratory infections (the flu, pharyngitis, sore throat).
Adverse weather affects the mental state, by forcing people to remain in enclosed spaces for a long time, or due to a decrease in natural light. This makes the brain produce less serotonin (a hormone that lifts the mood) and more melatonin (a sleep-inducing hormone), leading to sleepiness, bouts of depression and a decrease in the ability to focus.
The US National Health Statistics Center had shown back in 1978 that mortality is 15% greater in the cold season than in summer.
Air moisture impacts our health because it influences evaporation and affects our comfort.
Relative air moisture (used in the temperature comfort index) and vapor tension (a component of the formula for humidity-determining stress at skin level) are the parameters that define the effects of water vapors in the atmosphere on the human body.
A mass of warm air contains more moisture than a similar mass of colder air, and, therefore, humidity is greater during summer and during daytime. High humidity favors the development and spread of bacteria and other infectious agents, such as tuberculosis (TB), and prevents evaporation, which can cause pulmonary stress. This type of stress can also appear when there are few water vapors in the air, leading to dehydration and blood thickening.
The effects of wind are mostly negative, due to the fact that wind affects temperature and air pressure, and also carries insects and pollen. Fohn winds are warm and dry katabatic winds that descend from mountain slopes and are charged with positive ions that can influence the organism.
Wind stimulates skin nerves, stimulates perspiration and blood circulation, can have a negative impact on TB, asthma, chest pains, rheumatisms etc.
Electricity in the atmosphere requires a constant adaptation effort from the body, due to the constant fluctuations of this parameter due to the changing seasons and weather conditions (Povară R., 2006). Lightning can generate quite an intense physiological stress, whereas a positive electric field is beneficial for the organism, because it improves oxygenation. Many sanatoria are located in areas with such conditions.
An increase in the number of positive ions in the atmosphere leads to what is called by some scientists the “storm syndrome”, which manifests itself through decreased immunity, headaches, muscle pain, fatigue and other issues. Air ionization can help alleviate certain respiratory diseases, such as chronic bronchitis, asthma, and also high blood pressure and problems of the nervous system.
Solar radiations, which are in fact electromagnetic waves, can create negative physiological effects because they are able to penetrate human tissues.
Radio waves are stronger during thunderstorms and can also be amplified by industrial activities, and can cause spasms and a state of general agitation. Microwaves come from radio and TV signals, and when they exceed a certain threshold, they can cause dizziness, headaches and changes in the behavior.
Infra-red radiation is indispensable for life, intensifying the activity of white blood cells, which accelerates the metabolism, influencing blood pressure and the cardiac pulse. The human body cannot absorb all the IR, and has to selectively filter it through the skin. IR can help treat rheumatism and various injuries affecting the body’s joints. When the 1.5 – 3 Kcal/square centimeter of skin/minute threshold is exceeded, skin burns, thermal shock, sunstroke and eye damage (particularly on the retina), blood congestion in the spine and kidneys and respiratory problems can occur.
Visible radiations, or light, as we know it, have an alternating character, depending on the Earth’s movements and create the organism’s daily and annual biorhythms. A forced change in the biorhythm can cause sensory and mental imbalances.
Ultraviolet radiation determines a number of biological processes, such as the synthesis of vitamin D, which combats rickets, and also has photo-ionization effects, the most important being skin pigmentation (tanning), erythema (an inflammatory reaction in the skin caused by the dilation of blood vessels), the formation of skin cancers, blepharitis (an inflammation of the eyelid), cataract (a disease where the cornea becomes opaque) and hair damage. UV is beneficial in the treatment of acne, boils, varicose ulcer, sterilizing various products and in the synthesis of vitamin D2, which helps the absorption of calcium and phosphorus in the bones.
Article written by Aurelia Surdu and translated by Mihail Mitoseriu.