A collection of scientific and technical references on radiofrequency fields and cardiac outcomes.
The most-cited proposed non-thermal mechanism. Pulsed RF is reported to activate voltage-gated calcium channels in cell membranes, triggering oxidative stress and downstream cardiovascular effects, including tachycardia, arrhythmia, and sudden cardiac death. The effect is reported at power levels well below those required for tissue heating.
First reported in Germany in 1932 by Dr Erwin Schliephake after people were subjected to strong AM radio transmissions. During World War II, military personnel exposed to radar developed the same serious adverse health effects, known as "microwave sickness."
A study of 525 workers exposed to RF/MW radiation — published by Letavet and Gordon in 1960 — reported central-nervous-system-related disorders including hypotension, bradycardia (slower than normal heart rates), and elevated blood histamine content.
Silny (2007) reviews the demodulation of amplitude- or pulse-modulated electromagnetic waves in cell membranes. The review states that this "decreases the stimulation threshold of nerves and muscles and can introduce numerous adverse effects ranging from perception of pain to dangerous cardiac fibrillations."
The same review notes that pulse-modulated waves are demodulated in the electronic circuits of implants and "can inhibit cardiac pacemakers and introduce cardiac arrest in this way." The highest sensitivity results from repetition rates of pulses below 100 Hz — the range in which the PRF values documented in OTH-radar and jammer signatures fall.
A study of the Italian town of Potenza Picena, exposed to the EMF radiation of the military radar ARGOS 10 (located there from 1970 to 1998), analysed hospital admissions for 1986–1991. It found that "exposure to the radar radiofrequency emissions can increase the risk of cancer and heart diseases."
For heart-attack risk specifically, the comparison between exposed and fully exposed populations was reported as "highly significant," consistent with previous studies concluding that chronic RF exposure can bring about increased cardiovascular risk.
Pulsed microwaves can be perceived as sound — "clicks," "pops," or a "buzz" — without any receiving device, via thermoelastic expansion in tissue. The perceived character depends on pulse width, pulse repetition rate, and head geometry; the sensation may appear to originate behind, in, or above the head.
Watanabe et al. (2000) present a numerical FDTD analysis of the thermoelastic waves excited in a human head by pulsed microwaves, showing that surface heating is important in exciting the fundamental pressure-wave mode. The predicted vibration frequencies and threshold pressure amplitudes agree with experimental findings.
Robinette et al. (1980) assessed US Navy personnel exposed to radar microwave radiation during the Korean War. Comparing the cardiac mortality rate for "Diseases of the Circulatory System" in higher-exposed groups (FT+AT) versus the lower-exposed group (ET) yielded RR = 1.27 (95% CI: 0.92–1.75).
For hospital admissions, the results were statistically significant: diseases of blood-forming organs RR = 4.33 (95% CI: 1.53–12.3, p = 0.001); circulatory system RR = 1.53 (95% CI: 1.07–2.18, p = 0.007); cardiovascular disease RR = 2.03 (95% CI: 1.34–3.07, p < 0.001). The review concludes: "These military occupational groups exposed to radar have elevated cardiac mortality and highly significantly elevated cardiac disease rates."
The literature is not unanimous. Several systematic reviews report no consistent cardiovascular effect at exposure levels below thermal thresholds, while others report effects. Both directions are listed here so the reference set is not one-sided.