what is the maximum distance that the electromagnetic signal produced by a human heart can be detected?
Searching the web
50 results
The electromagnetic signal from a human heart primarily refers to the magnetic field generated by the electrical activity of the heart (measured via magnetocardiography, or MCG). This field is the strongest rhythmic biomagnetic signal produced by the body—roughly 100 times stronger than the brain's magnetic field.
heartmath.org
Standard Detection Range with Sensitive EquipmentUsing highly sensitive instruments like SQUID-based magnetometers (Superconducting Quantum Interference Devices), the heart's magnetic field can be reliably detected up to about 3 feet (approximately 1 meter) away from the body in all directions. This is a commonly cited figure from research by the HeartMath Institute and related studies. The field extends outward but weakens rapidly with distance (following the inverse-cube law for magnetic dipole fields at larger distances).
heartmath.org
At closer ranges:Peak amplitudes are typically 10–100 picotesla (pT) when measured a few centimeters (e.g., ~3 cm) above the chest.
The field is much stronger nearer the heart itself (on the order of nanotesla near the myocardium).
These measurements require magnetically shielded environments or extremely sensitive sensors because the heart's magnetic field is still very weak compared to Earth's magnetic field (~30–60 microtesla) or urban electromagnetic noise.
pmc.ncbi.nlm.nih.gov
Practical and Theoretical LimitsEveryday or less-sensitive detection: The signal drops off quickly and is not detectable by standard consumer devices beyond very short distances (centimeters to maybe a meter at best with advanced but non-SQUID sensors).
Theoretical maximum: In principle, with ideal, noise-free conditions and ultra-sensitive detectors (approaching femtotesla sensitivity), the signal could be picked up farther than 3 feet. However, real-world environmental noise, the field's rapid decay, and the need for signal averaging or shielding limit practical detection. Some speculative or less rigorously documented claims mention "several feet" or even a few meters, but these are not standard in peer-reviewed contexts.
facebook.com
No widely accepted scientific evidence supports detection at distances of tens of meters or more using purely passive electromagnetic sensing of the natural heart field.
Related Technologies (Not Pure Passive Detection)Some systems detect heart-related signals at much greater distances, but they differ from the natural electromagnetic field:Radar or Doppler-based systems (e.g., microwave or laser vibrometry like the Pentagon's Jetson prototype) can detect heartbeat signatures from up to 200 meters by sensing chest wall movements or reflections, not the heart's own bioelectromagnetic field.
technologyreview.com
Search-and-rescue radars (e.g., NASA's FINDER) can locate people via vital signs through rubble at tens of feet.
These are active sensing methods, not direct detection of the heart's emitted electromagnetic signal.Key DistinctionsThe electric component of the heart's signal (as in a standard ECG) is measured via skin contact and does not radiate far.
The magnetic component radiates more effectively but still only to ~1 meter with current sensitive lab instruments.
Claims of the field "reaching 3 feet" often come from popular summaries of HeartMath research, which used SQUID magnetometers for confirmation.
psychologytoday.com
In summary, the maximum reliably documented distance for detecting the human heart's natural electromagnetic (primarily magnetic) signal with specialized scientific equipment is on the order of 3 feet (~1 meter). Beyond that, practical limits due to field strength and noise make detection extremely challenging without active remote sensing techniques. For medical or research purposes, sensors are almost always placed very close to the body (centimeters).
Although such technology MIGHT be able to detect a human heartbeat from a few meters, perhaps even a few tens of meters, the inverse cube signal degradation makes it impossible to detect from the distances being reported. The technology may be good for finding people in rubble, or hiding behind a wall?, but certainly not for detecting someone from hundreds to thousands of meters away.
I would keep an open mind that maybe they are using something else instead of the magnetometers.
I am actually friend with a former Naval officer who was a weapon specialist. He won't tell me the details but he said even in the 60, they have developed tons of very sophisticated weapons and technology.
This is why this is BS, according to GROK:
what is the maximum distance that the electromagnetic signal produced by a human heart can be detected?
Searching the web
50 results
The electromagnetic signal from a human heart primarily refers to the magnetic field generated by the electrical activity of the heart (measured via magnetocardiography, or MCG). This field is the strongest rhythmic biomagnetic signal produced by the body—roughly 100 times stronger than the brain's magnetic field.
heartmath.org
Standard Detection Range with Sensitive EquipmentUsing highly sensitive instruments like SQUID-based magnetometers (Superconducting Quantum Interference Devices), the heart's magnetic field can be reliably detected up to about 3 feet (approximately 1 meter) away from the body in all directions. This is a commonly cited figure from research by the HeartMath Institute and related studies. The field extends outward but weakens rapidly with distance (following the inverse-cube law for magnetic dipole fields at larger distances).
heartmath.org
At closer ranges:Peak amplitudes are typically 10–100 picotesla (pT) when measured a few centimeters (e.g., ~3 cm) above the chest. The field is much stronger nearer the heart itself (on the order of nanotesla near the myocardium).
These measurements require magnetically shielded environments or extremely sensitive sensors because the heart's magnetic field is still very weak compared to Earth's magnetic field (~30–60 microtesla) or urban electromagnetic noise.
pmc.ncbi.nlm.nih.gov
Practical and Theoretical LimitsEveryday or less-sensitive detection: The signal drops off quickly and is not detectable by standard consumer devices beyond very short distances (centimeters to maybe a meter at best with advanced but non-SQUID sensors). Theoretical maximum: In principle, with ideal, noise-free conditions and ultra-sensitive detectors (approaching femtotesla sensitivity), the signal could be picked up farther than 3 feet. However, real-world environmental noise, the field's rapid decay, and the need for signal averaging or shielding limit practical detection. Some speculative or less rigorously documented claims mention "several feet" or even a few meters, but these are not standard in peer-reviewed contexts.
facebook.com
No widely accepted scientific evidence supports detection at distances of tens of meters or more using purely passive electromagnetic sensing of the natural heart field.
Related Technologies (Not Pure Passive Detection)Some systems detect heart-related signals at much greater distances, but they differ from the natural electromagnetic field:Radar or Doppler-based systems (e.g., microwave or laser vibrometry like the Pentagon's Jetson prototype) can detect heartbeat signatures from up to 200 meters by sensing chest wall movements or reflections, not the heart's own bioelectromagnetic field.
technologyreview.com
Search-and-rescue radars (e.g., NASA's FINDER) can locate people via vital signs through rubble at tens of feet.
These are active sensing methods, not direct detection of the heart's emitted electromagnetic signal.Key DistinctionsThe electric component of the heart's signal (as in a standard ECG) is measured via skin contact and does not radiate far. The magnetic component radiates more effectively but still only to ~1 meter with current sensitive lab instruments. Claims of the field "reaching 3 feet" often come from popular summaries of HeartMath research, which used SQUID magnetometers for confirmation.
psychologytoday.com
In summary, the maximum reliably documented distance for detecting the human heart's natural electromagnetic (primarily magnetic) signal with specialized scientific equipment is on the order of 3 feet (~1 meter). Beyond that, practical limits due to field strength and noise make detection extremely challenging without active remote sensing techniques. For medical or research purposes, sensors are almost always placed very close to the body (centimeters).
50 web pages
Although such technology MIGHT be able to detect a human heartbeat from a few meters, perhaps even a few tens of meters, the inverse cube signal degradation makes it impossible to detect from the distances being reported. The technology may be good for finding people in rubble, or hiding behind a wall?, but certainly not for detecting someone from hundreds to thousands of meters away.
I understand the skepticism.
I would keep an open mind that maybe they are using something else instead of the magnetometers.
I am actually friend with a former Naval officer who was a weapon specialist. He won't tell me the details but he said even in the 60, they have developed tons of very sophisticated weapons and technology.