According to popular wisdom, the link between climatic conditions and our minor and major ailments no longer needs to be proven. Attendance at medical offices and emergency services also increases in cold, humid or excessively hot weather. If the link between the weather and certain diseases such as heart attack is proven, for others it is more random and can only be explained indirectly: in bad weather we go out less, we exercise less, we eat fatter… Perceived quality of life and morale are affected. Here’s what we know so far about the influence of different types of weather
Dry cold increases heart and respiratory problems
The more the temperature drops below 0°C, the more hospitalizations and deaths from heart attacks increase. This is shown by a recent Canadian study (1). The cold causes a contraction of the vessels, it increases the arterial pressure and the viscosity of the blood, while the heart rate accelerates, hence more risk of clots and thrombosis, therefore of infarction. This mechanism also promotes angina attacks and strokes. Inhalation of cold air can trigger an asthma attack, especially in the event of effort, by causing constriction of the bronchi and respiratory spasm. In winter, the mucous membranes of the nose and throat defend themselves less well against attacks. And since we tend to stay indoors and ventilate less, germs proliferate and infections spread. The cold can also cause cracks (it dries out the skin), frostbite or Raynaud’s syndrome (it contracts the vessels).
Damp cold aggravates rheumatic pains
If there is one area where the weather has the reputation of playing an important role, even of serving as a barometer, it is in rheumatism. A majority of people with joint pain complain about the influence of time on pain and stiffness. They are increased by cold, humidity, the drop in pressure when bad weather approaches, or more rarely by heat… Sensitivity to atmospheric pressure (also sometimes felt during an airplane flight) is explained: the air presses with a certain force on the tissues, reducing their congestion when they are inflamed. Humidity, rain and fog also increase respiratory infections: they cause bacteria, viruses and pollutants carried by the wind to fall back to earth.
Wind promotes migraine, stroke and asthma
According to Chinese medicine, the wind upsets the energy balance. Autan wind, mistral, tramontana, foehn… Some winds are said to “drive you crazy”. What is certain is that the wind increases irritability and promotes headaches, migraines and insomnia. The frequency of cerebrovascular accidents (CVA) increases in winter in anticyclonic weather (low temperature, low humidity), especially when the wind speed is high. The harder it blows, the lower the temperature feels, hence an exacerbation of cold-related health problems.
In pollen season, from spring to autumn, dry and windy weather carries allergens and increases the risk of respiratory allergies (rhinitis, allergic asthma) and conjunctivitis.
Heat causes dehydration and heart attacks
The heat can be dangerous if it turns into a heat wave (for example in Paris, more than 31°C during the day and 21°C at night for three days in a row). Young children, the elderly or those suffering from a chronic illness are particularly exposed to the risk of dehydration: fatigue, risk of confusion, heat stroke, but also cramps, renal colic… And increased attacks in people suffering from schizophrenia or depression.
Even a moderate increase in heat (from 20°C to 25°C over 2 days) is associated with more deaths from heart failure, stroke and arrhythmia (2). This would be explained in particular by an increase in the workload of the heart, dehydration and salt depletion.
Pollution also plays a role
It further amplifies the consequences of the weather on health, in different ways depending on the season:
– Ozone pollution: in summer, in hot and sunny weather: it especially aggravates respiratory problems.
– Pollution with fine particles: in winter, in cloudy weather without wind: it especially increases the cardiovascular risk.
(1) Canadian study presented at the ESC congress in September 2015 (Liu S.)
(2) German study of 188,000 people, published in the journal Heart in 2014 (Breitner S.)
For further
What effect does the weather have on our libido?
Back pain: should we blame the weather?
