The weather-headache nexus

How do insights arise?

Many of the research studies follow a similar procedure. People with migraines or tension-type headaches keep a headache diary over a certain period of time, meticulously recording their pain episodes along with details like severity and duration.

These records are then compared with weather data (such as air pressure, temperature, humidity, precipitation, and wind), usually from the nearest weather station. Researchers also monitor changes like falling air pressure or rising temperatures, as many people link their attacks to shifts in the weather. This process generates a vast amount of data, which is then analyzed using mathematical models to compare the patient records with the weather data.

The goal is to identify statistically significant correlations between certain combinations of weather conditions and headaches. In this article, we present several studies and attempt to nail down the current understanding.

Results may vary

A study at Charité hospital, Berlin matched migraine patients’ headache diaries with weather data over a year. In six out of 20 patients, a clear link was found between migraine attacks and simultaneous weather events; specifically, a drop in temperature accompanied by rising humidity.

In their interpretation of the results, the authors included a possible impact of genetic factors, suggesting that some individuals may be born more sensitive than others to changes in the weather. This could explain why correlations were found only in a subset of participants. However, the researchers acknowledged the difficulty of pinpointing causes and effects given the many variables at play, including the patients’ current state of health, genetic predisposition, and measured weather data.

That said, the authors go on to propose that habitual migraine sufferers may indeed be genetically predisposed to react to weather processes.

Mosaic pieces, but no picture

Authors of a more recent study point out the limitations of existing headache-weather research, which they attribute to the highly inconsistent design and methodology of the various studies available. These differences make it extremely hard to draw reliable conclusions. To complicate matters, there is no definitive evidence showing how the weather affects our bodies and how such effects are mediated. No specific organ or system has been identified as responsible for these effects. At best, the findings are like pieces of a mosaic that may one day add up to a complete picture. Here are some examples:

Geomagnetism: Some publications speculate that the Earth’s magnetic field might play a role, with geomagnetic activity potentially linked to headaches. Amid all these speculations, nobody knows how our bodies would detect such activity. No sensory organ or brain area has been found that might support this function.

Temperature and pressure: On a positive note, we do know for sure that certain nerve pathways are affected by temperature and pressure changes. Also, animal studies in certain disease models show an effect of air pressure on pain sensitivity. However, we still lack a clear understanding on how these individual findings fit into the overall picture of headache disorders.

Inflammation: Another line of inquiry looks at the inflammatory processes long thought to be involved in causing migraine attacks. According to this theory, fluctuations in ambient temperature, pressure and humidity could lead to increased production of inflammatory chemicals and activation of immune cells, causing localized inflammation that either causes pain on its own, or helps trigger migraines.

Looking at the many individual observations on the effects of weather on our bodies, it’s clear how difficult it is to create a coherent narrative of cause and effect from these “bits and pieces”.

Are perceptions truths?

In a study at the University of Vienna study, patients kept a headache diary every day for three months. These meticulous and extensive records included the patients’ personal perceptions of the weather. Initial analysis suggested identifiable links. Deeper mathematical examination did not confirm these connections, however. This highlights a fundamental limitation of self-reported studies. Many people firmly believe, based solely on their own subjective perception, that there is a strong connection between weather (changes) and their headaches. Nevertheless, these perceptions rarely hold up under scientific scrutiny.

Can high-tech solutions help?

A team of Japanese scientists used a smartphone app to collect data from a large number of users about their headaches. The information was matched against a vast amount of weather data to look for patterns. Artificial intelligence (AI) was employed to analyze the data.

The results showed that low barometric pressure, high humidity, and rainfall constituted a headache risk for many participants. A drop in air pressure before and during attacks was identified as significant. The results are consistent with outcomes of earlier studies demonstrating a significant impact of weather changes rather than (stable) weather as such. Again, however, this study failed to identify a precise cause-effect relationship. While there is evidence suggesting that factors like humidity, cold, and rainfall can contribute to headaches and occasionally trigger migraine attacks, it remains challenging to draw conclusive assumptions from purely descriptive correlations about which processes are responsible for signal processing in the run-up to an attack.

The elusive search for proof

Few areas of research produce a more mixed bag of results and claims than the headache-weather connection. If you believe science can shed reliable light on what’s going on here, think again. While it is clear that our bodies react to weather, and that some people are more sensitive to changes, that’s about all anybody can say for sure.

As Angela Schuh, Professor of Medical Climatology at Ludwig Maximilian University (LMU) Munich, suggests in her book “Bioweather”, weather-related headaches may be partly due to the fact that our bodies are out of practice, preventing us from adapting quickly and correctly to different weather conditions. Furthermore, modern lifestyles – working indoors, getting too little daylight, maintaining irregular schedules – could also contribute to headaches in sensitive individuals.