Biometeorology is the study of the impact weather has on the natural world, including animals, plants and humans. This includes the impact on symptoms of existing diseases, contribution to new conditions and temporary physiological changes. There are a number of illnesses and symptoms that are caused or exacerbated by certain types of weather. Here we discuss some of the more obvious conditions, as well as some, perhaps, more surprising ailments.
Cold and flu
Many people claim to be struck down with the common cold during colder seasons or when the weather rapidly changes. Although it’s not entirely clear why, scientists believe it’s because rapid temperature swings weaken your immune system and cold viruses transmit better in cold air. When atmospheric pressure changes, many people also feel it acutely in their sinuses.
Asthma and allergies
Changing seasons (the growing season in particular), air pollution and certain weather conditions (i.e. heat, extreme cold, fog) can exacerbate asthma and other allergies. A geographic understanding of these impacts can help people manage their symptoms (see tWC article on British Hay Fever Maps).
As atmospheric pressure decreases, blood pressure drops. This means that when low pressure systems (depression) are driving the weather, blood pressure, on the whole, is lower. Furthermore, low temperatures also cause blood vessels to narrow, meaning blood pressure is generally lower in the summer and higher in the winter. Such changes to blood pressure can have an impact on many other illnesses, as a knock-on effect.
Sudden changes in atmospheric pressure, such as the drop in pressure that occurs prior to a storm, can trigger joint pain. Research has also indicated that cold weather can cause painful changes in joint fluid thickness. Regular exposure to sunlight, specifically ultraviolet B (UV-B), is also thought to reduce the risk of developing rheumatoid arthritis. (See tWC article theweatherclub.org.uk/node/322)
Atmospheric pressure is known to trigger headaches and migraines, though the precise reason is unclear. It may be that it effects the pressure in the brain or the way the brain blocks pain, or it may even be linked to evolution as a way of keeping humans in tune with the environment. The time of the year can also impact on headaches, as longer exposure to bright light and, for those with allergies, pollen exposure, can trigger migraines and headaches.
Blood-sugar changes and diabetes
During weather fronts, which are associated with low atmospheric pressure, blood viscosity, or thickness, increases. This may mean that diabetics may have more trouble controlling their blood sugar during the passage of a cold front.
According to research, each 1 degree Celsius drop in temperature is associated with around 200 additional heart attacks across the US. Higher blood pressure and an increased risk of blood clots are thought to contribute to the risk.
Hot, humid weather and air pollution (which can worsen during hot weather) can make breathing difficult, particularly for people with pre-existing lung conditions such as chronic obstructive pulmonary disease.
Extreme heat can cause heat stress. This is when the body’s means of controlling its internal temperature starts to fail and can be fatal. (See tWC article).
Although certain aspects of the weather have been pin-pointed to cause or exacerbate symptoms and illnesses, it can often be a combination of factors that have an impact; For example, is a change in temperature affecting a person’s well-being, or is it the change in pressure, air quality or humidity, or a combination of them all? Furthermore, there are still other illnesses which may have a link to the weather, yet this link is still be recognised. Climate change will continue to have an impact on human health - both physically and emotionally – via changes to the weather and other environmental and sociological pathways. Health professionals in hospitals, surgeries and emergency services need to be aware of impending weather events that may have an impact on health in order to predict and plan for likely outcomes. With increasing research into the field of biometeorology, such short-and long-term impacts can be better anticipated.