This study accounted for weather, and found an increased rate of nearly 30 percent in heart attacks (MI) during geomagnetic storms. https://doi.org/10.1007/s00484-013-0660-0 That is massive, akin to the increase you'd expect during an environmental catastrophe, such as a severe heatwave or something.
The narrative isn't so much the static magnetic field but fluctuating/time varying magnetic fields induced on Earth during magnetic storms. When a magnetic field changes it can induce currents in tissues. It's proportional to both the strength of the field and the rate of change. During an extreme geomagnetic storm, the rate of change can be up to 500 nanoteslas per minute.
It's being argued that these tiny (less than 1% of Earth's static field strength) fluctuations in Earth's magnetic field are stressing cells and the body, resulting in the correlations between geomagnetic storms and heart attacks, strokes, autonomic dysfunction, and other serious illnesses.
Mine did, too, then I looked into it and it does seem there's a lot of research concluding that fluctuations in the Earth's magnetic field during geomagnetic storms is causing more heart attacks, nervous system dysregulation, etc. https://magneticstorms.co/health/heart but I'm not as well versed in science compared to many of the people on Lemmy.
I thought so, too, but it does seem like a lot of seemingly reputable sources are talking about it as if it's common knowledge now.. https://magneticstorms.co/health/heart and yeah, good point! I think there are sites where you can track space weather, but if someone's a paramedic I'd hope they'd be tracking patients more than space weather..