Geomagnetic disturbances caused by the Sun influence the occurrence of heart attacks, especially among women

To reach this conclusion, Brazilian researchers cross-referenced data obtained from the local public health network with data from an indicator of variations in the Earth’s geomagnetic field. The study was published in the journal Communications Medicine.

By Karina Toledo  |  Agência FAPESP – An article published in the journal Communications Medicine points to a correlation between disturbances in the Earth’s magnetic field resulting from solar storms and an increase in the frequency of heart attacks, especially among women.

The authors reached this conclusion by analyzing data from the public health network of São José dos Campos, in the state of São Paulo, Brazil, recorded between 1998 and 2005, a period considered to be one of intense solar activity. Focusing on hospital admissions for myocardial infarction, the analysis included information from 871 men and 469 women. Data from the Planetary Index (Kp-Index), an indicator of variations in the Earth’s geomagnetic field, were also incorporated into the statistical analysis.

“We classified the days analyzed as calm, moderate, or disturbed. And the health data were divided by sex and age group [up to 30 years old; between 31 and 60; over 60 years old]. It’s worth noting that the number of heart attacks among men is almost twice as high – regardless of geomagnetic conditions. But when we look at the relative frequency rate of cases, we find that for women, it’s significantly higher during disturbed geomagnetic conditions compared to calm conditions. In the 31-60 age group, it’s up to three times higher. Therefore, our results suggest that women are more susceptible to geomagnetic conditions,” Luiz Felipe Campos de Rezende, a researcher at Brazil’s National Institute for Space Research (INPE) and the corresponding author of the article, told Agência FAPESP.

As Rezende explains, geomagnetic disturbances are caused by the impact of the solar wind on the magnetosphere, the outermost region of the atmosphere where the solar wind meets the Earth’s magnetic field. The effects of these disturbances on satellite communications and global positioning systems (GPS) are well known.

Since the late 1970s, studies conducted in the Northern Hemisphere have suggested that magnetic particles ejected by the Sun may also have an impact on human health, particularly the cardiovascular system. Data from these studies suggest possible explanations, such as changes in blood pressure, heart rate, and circadian rhythm, which regulates the sleep-wake cycle and all bodily functions. However, this remains an open scientific question.

“This is the first study on the subject conducted in our latitudes, but it isn’t conclusive. Therefore, the intention isn’t to cause alarm among the population, particularly among women. There are some limitations to consider: this is an observational study conducted in a single city, using a sample size that isn’t yet ideal for medical questions. However, we believe that these findings represent an empirical result of hypothetical significance and relevance that shouldn’t be disregarded in the scientific context,” the researcher says.

This also appears to be the first, or at least one of the few studies, to suggest that women are more susceptible to geomagnetic disturbances. The article did not explore the causes of this phenomenon. “We didn’t find any significant publications on this subject in the literature. It’s a question for future studies,” Rezende points out.

Prediction and prevention

The Sun undergoes cycles of increased and decreased magnetic activity, averaging 11 years. It is estimated that the “solar maximum” phase occurred between late 2024 and early 2025. This is the period of the cycle with the highest magnetic activity. According to experts, 2025 will be a year of high solar activity. However, it is worth noting that disturbances in the Earth’s magnetic field occur sporadically. INPE maintains a website that monitors these variations.

“Scientists around the world have been trying to predict the occurrence of geomagnetic disturbances, but the accuracy, for now, isn’t good. When this type of service is more advanced – and if the impact of magnetic disturbances on the heart is confirmed – we’ll be able to consider prevention strategies from a public health perspective, especially for individuals who already suffer from heart problems,” Rezende says.

The article “Influence of geomagnetic disturbances on myocardial infarctions in women and men from Brazil” can be read at www.nature.com/articles/s43856-025-00887-7.