If you’re a woman managing a heart condition, here’s a question worth asking: can a geomagnetic storm change your heart attack risk? A 2025 study from Brazil’s National Institute for Space Research suggests it might. When the researchers lined up heart attack admissions against geomagnetic conditions, women’s heart attacks clustered on magnetically disturbed days more than men’s did — a hint that has also surfaced, in a different form, in a Lithuanian dataset, though the science is far from settled.
The short answer: Women appear to have more heart attacks on geomagnetically disturbed days than on quiet ones — at least in one Brazilian city, where about 11.2% of women’s cases in the 31–60 age group fell on disturbed days versus 7.1% on quiet days (Rezende and colleagues, 2025), while men showed no comparable increase. It’s an association from a single observational study, not proof that a geomagnetic storm causes heart attacks, but it lines up with older research enough to be worth your attention.
First, what a “geomagnetic storm” even is
The Sun constantly blows a stream of charged particles past us — the solar wind. Every so often it hurls a much bigger cloud our way, a coronal mass ejection. When that cloud slams into Earth’s magnetic field 93 million miles downstream, the field wobbles, and we call the wobble a geomagnetic storm. Most of them do nothing more dramatic than paint the sky green near the poles. We covered the broad strokes of the heart connection in Do geomagnetic storms increase heart attack risk?; this piece zooms in on the part that’s drawn the most recent interest — sex differences.
Scientists rate how disturbed the field is with indices like Kp (more on that in What is Kp, and why does FlareAware care?). Quiet days sit low on the scale; disturbed days climb. Researchers then do something simple: they line up hospital records against the calendar of quiet versus disturbed days and ask whether the heart attacks bunch up when the field is rattled.
What the Brazil study actually found
The study, led by Luiz Felipe Rezende and colleagues (2025), examined the records of 1,340 heart attack patients — 871 men and 469 women — admitted in São José dos Campos between 1998 and 2005, years that included the maximum of Solar Cycle 23 around 2000–2002. Each admission was sorted by whether the geomagnetic field that day was quiet, moderate, or disturbed. The female pattern was the notable one: among women aged 31–60, the relative frequency of heart attacks was about 11.2% on disturbed days versus 7.1% on quiet days. Men, who accounted for nearly twice as many heart attacks overall, did not show a comparable increase tied to geomagnetic conditions.
A few honest caveats, because they matter. This is one city, a few hundred women, looking backward at records — correlation, not causation, and the authors don’t claim otherwise. A 2026 author correction to the paper restated the underlying day counts (2,042 quiet, 452 moderate, 214 disturbed days), which is worth knowing if you read the original closely; it doesn’t overturn the female-versus-male pattern. So the real question is whether anyone else, anywhere, has seen something similar.
A second study, in Lithuania
Someone has. A few years earlier, a team tracked 703 heart attack patients — 435 men and 268 women — against minute-by-minute readings of the local magnetic field (Jaruševičius et al., 2018). For women, higher activity in one high-frequency band (the gamma range, ~32–65 Hz) showed a weak positive correlation with the most dangerous kind of heart attack, the STEMI (r = 0.25). For men, the correlations in that band were negative but not statistically significant. The authors read this cautiously, suggesting it “may indicate slightly different sensitivity of different sexes,” and flagged that age and sex differences between their groups could confound the result. It’s a small, observational signal, and it measures something different from the Brazil study, but it leans in a broadly compatible direction — which is why the two are worth mentioning together: consistent with a possible sex-specific sensitivity, not proof of one.
How might a storm reach the heart?
This is where it moves from numerology toward physiology — though everything here is proposed, not settled. One idea is almost musical. Earth’s field doesn’t just swell and fade during a storm; it rings, producing rapid pulsations. One type, Pc1, oscillates with a period of roughly 0.2–5 seconds, which overlaps the rhythm of a beating human heart. Analyzing 85,700 heart attack ambulance calls in Moscow, Kleimenova and colleagues (2007) found Pc1 pulsations present on about 70% of the days with an abnormal spike in heart attacks, and proposed a “stochastic resonance” mechanism — the notion that a weak, well-tuned signal can nudge an already-unstable system toward an irregular rhythm.
Two other doors have been studied. The first is the autonomic nervous system, the autopilot behind your heart rate and blood pressure. In a five-month study that enrolled 18 healthy women (16 analyzed), Alabdulgader and colleagues (2018) found that heart rate variability shifts with solar and geomagnetic activity even on calm days, and that higher solar wind intensity correlated with a higher heart rate, which they interpreted as a stress response. The second door is blood pressure. Following 447 untreated patients over five years and using a local geomagnetic index (the k-sum, not the planetary Kp), Ghione and colleagues (1998) found systolic and diastolic pressure ran about 6–8 mmHg higher on the most disturbed days, with no link to heart rate.
Put those together and you don’t get a proven pathway — you get a hypothesis. A jumpier nervous system, a modest bump in blood pressure, and a pacemaker that may be sensitive to field pulsations could, in principle, matter more in someone whose arteries are already vulnerable. “Could, in principle” is doing real work in that sentence, and it’s meant to.
Why women? Nobody’s sure yet
Some perspective on size first. Pooling the broader literature, a 2025 systematic review and meta-analysis of six studies put the heart attack and acute-coronary-syndrome risk during geomagnetic storms at a mean relative risk of roughly 1.3–1.5 across those studies (Gaisenok et al., 2025) — a 30–50% increase across the general population, not a dramatic one. Against that backdrop, why would women show up more strongly in the Brazil and Lithuania data? Honestly, no one knows yet. The Brazil authors point to possible differences in cardiac autonomic regulation and in antioxidant and metabolic factors between the sexes. Broader physiological and hormonal differences are an obvious place to look, but those remain open questions rather than established explanations — the repeated finding is that women seem to respond differently; the why is still unresolved.
What to do with this
So what do you actually do? Not move to the equator, and not dread the next aurora. The effect is a statistical nudge, and the overwhelming majority of disturbed days pass without incident. But if you’re a woman, particularly in mid-life and particularly if you’re already managing high blood pressure, diabetes, or known heart disease, a strong geomagnetic storm is a reasonable prompt to stick to your usual care plan and pay attention to how you feel. Heart attacks don’t always announce themselves the same way in women: alongside chest pain, the American Heart Association notes that women more often report quieter symptoms such as unusual fatigue, shortness of breath, nausea, or pain in the jaw, neck, back, or arm (American Heart Association, n.d.). Those are easy to talk yourself out of, so take them seriously whenever they show up — and if you think something is genuinely wrong, don’t wait it out; get help. A storm alert can’t diagnose anything. What it can do is give you one more reason not to brush off an odd symptom on a day when the odds are slightly tilted.
Timing makes this relevant right now. NOAA’s forecast panel projected Solar Cycle 25 to peak around July 2025, within a window running from late 2024 into early 2026 (NOAA SWPC, Solar Cycle Progression). As of mid-2026, in other words, we’re at or just past the cycle’s maximum — the stretch when disturbed days arrive more often than they do during the quiet years between cycles.
Knowing it’s coming
Unlike your blood pressure, you can’t feel the magnetic field move. That’s the gap FlareAware fills: it monitors NOAA’s geomagnetic activity data and sends you a heads-up when a storm is on the way, so you can be a little more careful on the days that warrant it and get on with your life on the days that don’t. You can set that up at flareaware.com.
One non-negotiable note: this is general information, not medical advice. Nothing here replaces your doctor, none of it should change your medication without their say-so, and if you think you’re having a heart attack, call emergency services — storm or no storm.
References
Rezende, L. F. C., De Paula, E. R., Muella, M. T. A. H., Dutra, S. L. G., Rosa, R. R., Saldiva, P. H. N., & Ometto, J. P. H. B. (2025). “Influence of geomagnetic disturbances on myocardial infarctions in women and men from Brazil.” Communications Medicine, 5. DOI: 10.1038/s43856-025-00887-7
Rezende, L. F. C., De Paula, E. R., Muella, M. T. A. H., Dutra, S. L. G., Rosa, R. R., Saldiva, P. H. N., & Ometto, J. P. H. B. (2026). “Author Correction: Influence of geomagnetic disturbances on myocardial infarctions in women and men from Brazil.” Communications Medicine. DOI: 10.1038/s43856-026-01478-w
Jaruševičius, G., Rugelis, T., McCraty, R., Landauskas, M., Berškienė, K., & Vainoras, A. (2018). “Correlation between Changes in Local Earth’s Magnetic Field and Cases of Acute Myocardial Infarction.” International Journal of Environmental Research and Public Health, 15(3), 399. DOI: 10.3390/ijerph15030399
Kleimenova, N. G., Kozyreva, O. V., Breus, T. K., & Rapoport, S. I. (2007). “Seasonal Variations in Myocardial Infarctions and the Possible Biotropic Influence of Short-Period Geomagnetic Pulsations on the Human Cardiovascular System.” Biophysics, 52(6), 625–631. DOI: 10.1134/S0006350907060152
Alabdulgader, A., McCraty, R., Atkinson, M., Dobyns, Y., Vainoras, A., Ragulskis, M., & Stolc, V. (2018). “Long-Term Study of Heart Rate Variability Responses to Changes in the Solar and Geomagnetic Environment.” Scientific Reports, 8, 2663. DOI: 10.1038/s41598-018-20932-x
Ghione, S., Mezzasalma, L., Del Seppia, C., & Papi, F. (1998). “Do geomagnetic disturbances of solar origin affect arterial blood pressure?” Journal of Human Hypertension, 12(11), 749–754. DOI: 10.1038/sj.jhh.1000708
Gaisenok, O., Gaisenok, D., & Bogachev, S. (2025). “The Influence of Geomagnetic Storms on the Risks of Developing Myocardial Infarction, Acute Coronary Syndrome, and Stroke: Systematic Review and Meta-analysis.” Journal of Medical Physics, 50(1). DOI: 10.4103/jmp.jmp_122_24
NOAA Space Weather Prediction Center. “Solar Cycle Progression.” https://www.swpc.noaa.gov/products/solar-cycle-progression
American Heart Association (n.d.). “Heart Attack Symptoms in Women.” https://www.heart.org/en/health-topics/heart-attack/warning-signs-of-a-heart-attack/heart-attack-symptoms-in-women
