Biometeorology is the study of  the impact of weather and climate on living things including plants and animals. The effect of weather on living things has been informally observed, noted and manipulated by mankind from its very beginning. For example:

  • Agriculture is known to have developed at least 10,000 years ago and its successful outcome involved farmers developing an understanding of the relationship between weather and crop cycles and growth.
  • Fishermen have been aware for millennia of the interaction between weather conditions and their catch. Since the advent of the barometer, they have realized that shallow and fresh waters are affected more by changes in air pressure than deep waters.
  • The ability of birds to respond to changes in weather and the seasons of the year has been appreciated from antiquity. Interestingly, we now believe that they are able to detect changes in barometric pressure due to expansion and contraction of sealed air sacs or cavities in a manner analogous to that of an altimeter or barometer.

As long ago as 400 BC, the ancient Greek physician Hippocrates wrote about the effect of weather on people and it has been known throughout the ages that certain medical conditions, e.g. rheumatoid arthritis, are directly affected by weather conditions and humidity. Also, the ability of some people and animals to sense the arrival of a weather front hours or days in advance has also been recorded. However, the study of headaches due to weather-related variables (such as barometric pressure, humidity and temperature) though widely cited, is poorly documented in scientific literature.

Aside from the weather, Barometric Pressure Headaches can be experienced by people who take part in certain altitude related activities such as flying, mountaineering  or travelling to new locations at differing elevations. Air or barometric pressure exhibits an inverse relationship to altitude i.e. higher altitudes= lower pressure and lower altitudes= higher pressure.

Unfortunately, although numerous studies confirm what people have known for millennia ( i.e.that weather and altitude significantly affect living things, including causing headaches in weather or altitude sensitive people), at present, there appears to be no single and definitive explanation universally accepted to explain the precise mechanism and biological response to account for Barometric Pressure Headaches. Various explanations have been suggested which include the possibility that changes or fluctuations in barometric pressure are associated with:

  • Alterations in oxygen levels that result in blood and cranial vessels trying to compensate by contracting (vasoconstriction) and/or dilating (vasodilation) in the head region. Pain is caused by swollen blood vessels pressing on nerve fibres in the brain as well as from swelling/inflammation of brain tissue from various chemicals released during this process. This was the most popular explanation of migraines from the medical profession prior to the development of modern resonance imaging techniques. These now indicate that migraines are not simply due to blood flow changes but are much more complex in nature involving various changes in the brain.
  • Vasodilation of blood vessels in head due to barometric receptors in the brain being activated.
  • Atmospheric electrically charged/ionization of air particles that trigger headaches. Positive ionization has been linked to the release of excessive serotonin into the bloodstream.
  • Triggers involving changes in electrical activity within the brain.
  • Triggers involving pressure induced chemical changes occurring in the body.
  • Producing small pressure variations in the fluid of the brain that trigger brainstem migraine receptors.
  • Changes in neurotransmitters of the brain.
  • Differences in pressure concerning blood vessels, numerous tubes, cavities and sealed chambers filled with fluid or air in the inner ear, brain and head region. In particular, pain resulting from pressure differences between air trapped in the sinuses and the air outside (especially when barometric pressure decreases) which becomes exacerbated when the openings leading into the nasal cavities are blocked, is well documented.

Studies have shown many other factors may possibly trigger headaches and migraines through influencing brain patterns, nerves and body chemistry. Understanding the exact degree of association between the weather/barometric pressure and these factors is still to be determined:

  • Environmental electromagnetism.
  • Changes in the earth’s electromagnetic field during solar storms.
  • Air-borne particulate matter and pollutants especially in cities.