SQUID Magnetometry and Biomagnetic Fields: Measuring the Invisible Force of Healing Hands

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The Quietest Instrument Ever Built

Somewhere in a basement laboratory, shielded by layers of mu-metal and aluminum designed to block the Earth’s magnetic field and every stray electromagnetic signal from the civilization above, sits a device cooled to four degrees above absolute zero. Inside its cryogenic chamber, a tiny loop of niobium wire has become superconducting — its electrical resistance has dropped to exactly zero, and it has become sensitive to magnetic fields so faint that they are measured in femtotesla: quadrillionths of a Tesla.

This is a SQUID — a Superconducting Quantum Interference Device. It is, by several orders of magnitude, the most sensitive magnetic field detector ever constructed by human beings. It can detect magnetic fields one billion times weaker than a refrigerator magnet. It can measure the magnetic field produced by a single firing neuron. It can detect the magnetic signal generated by the electrical current flowing through your heart from across a room.

And in the early 1990s, a researcher named John Zimmerman pointed one at the hands of a Therapeutic Touch practitioner — and measured something that changed the conversation about energy healing forever.

Biomagnetic Fields: The Body’s Magnetic Signature

Every electrical current produces a magnetic field. This is not metaphysics — it is Maxwell’s equations, one of the most thoroughly validated laws in all of physics. And the human body is an electrical system. The heart generates electrical currents measured by the electrocardiogram (ECG). The brain generates electrical currents measured by the electroencephalogram (EEG). Muscles generate electrical currents measured by electromyography (EMG). Every nerve impulse, every ion channel opening, every cellular process that involves the movement of charged particles produces a corresponding magnetic field.

These biomagnetic fields are extraordinarily weak. The heart’s magnetic field — the strongest biomagnetic signal in the body — peaks at about 50 picotesla (50 trillionths of a Tesla) directly over the chest. The brain’s magnetic field is roughly a thousand times weaker, around 100-1000 femtotesla. For comparison, the Earth’s magnetic field is about 50 microtesla — a million times stronger than the heart’s field and a billion times stronger than the brain’s.

This is why biomagnetic fields were not detected until the late 1960s, when David Cohen at MIT first used a SQUID magnetometer to record a magnetocardiogram (MCG) — the magnetic equivalent of an ECG. Cohen went on to record the first magnetoencephalogram (MEG) — the magnetic equivalent of an EEG — in 1972.

Why Magnetic Fields Matter

You might reasonably ask: if we already have the ECG and EEG, which measure the same electrical activity that produces these magnetic fields, why bother with the far more difficult task of measuring the magnetic component?

The answer reveals a fundamental advantage of magnetic measurement:

No contact required. ECG and EEG require electrodes placed on the skin, which introduces impedance matching problems, skin preparation requirements, and physical constraints. Magnetic fields pass through the body and air unimpeded, and can be measured at a distance without touching the subject.

No volume conduction distortion. Electrical signals are distorted as they pass through the varying conductivities of brain tissue, skull, and scalp. This “volume conduction” smears the electrical signal, making it difficult to localize its source. Magnetic fields are not distorted by tissue conductivity, providing much better spatial resolution for source localization.

Frequency content preserved. The frequency spectrum of the magnetic signal is preserved without the filtering effects of tissue impedance, providing a cleaner picture of the underlying neural activity.

Three-dimensional information. The vector nature of magnetic fields provides information about the orientation and direction of current flow that is not available from surface electrical measurements.

These advantages made SQUID magnetometry the gold standard for functional brain imaging throughout the 1980s and 1990s — and they also made it the ideal instrument for asking a question that had never been rigorously asked before: Do the hands of healers produce measurable electromagnetic fields?

John Zimmerman and the Therapeutic Touch Experiments

John Zimmerman was a researcher at the University of Colorado School of Medicine in Denver. In the late 1980s, he became interested in a seemingly simple question: Therapeutic Touch (TT) practitioners claim to manipulate a patient’s “energy field” with their hands. Is there anything measurable coming from their hands?

Therapeutic Touch, developed in the 1970s by Dolores Krieger (a nursing professor at New York University) and Dora Kunz (a natural healer), involves the practitioner holding their hands near the patient’s body — typically two to six inches away — and using intention to detect and manipulate what they describe as the patient’s “energy field.” Despite its name, Therapeutic Touch often involves no physical contact at all.

The practice had been controversial since its inception. Skeptics argued that there was no known physical mechanism by which one person’s hands could affect another person’s physiology without contact. Proponents pointed to clinical studies showing measurable effects — reduced anxiety, accelerated wound healing, altered immune markers — and argued that the mechanism would be discovered eventually.

Zimmerman decided to look for the mechanism. He placed Therapeutic Touch practitioners in a magnetically shielded room and measured the magnetic field emissions from their hands using a SQUID magnetometer.

The Results

Zimmerman’s findings, published in 1990, were remarkable:

Baseline measurements. When the practitioners were at rest, not performing healing, the magnetic field from their hands was in the range expected for any human hand — roughly 1-10 femtotesla, barely above the noise floor of the instrument.

During healing intention. When the practitioners entered a healing state — focusing their intention and performing the characteristic hand movements of Therapeutic Touch — the magnetic field from their hands increased dramatically: by a factor of approximately 1,000, reaching levels of 1-10 picotesla and in some cases exceeding 100 picotesla.

Frequency characteristics. The enhanced magnetic signal was not static. It pulsed at frequencies between 0.3 and 30 Hz, with the strongest emissions in the range of 7-8 Hz. This frequency range is significant — it overlaps with the frequencies used in pulsed electromagnetic field (PEMF) therapy, which has been clinically validated for bone healing, pain relief, and tissue repair.

Specificity. Not all practitioners produced the same signal. The strength and frequency characteristics varied between practitioners, and correlated to some degree with the practitioner’s experience and reported “felt sense” of energy flow.

The PEMF Connection

The overlap between the healer’s hand emissions and therapeutic PEMF frequencies is perhaps the most significant finding in the entire field of biofield research.

Pulsed electromagnetic field therapy has been approved by the FDA for the treatment of non-union bone fractures since 1979. The therapeutic frequencies range from 2 to 50 Hz, with the most effective frequencies for bone healing clustered around 7-8 Hz. These same frequencies have been shown to promote cartilage repair, nerve regeneration, wound healing, and pain relief.

Zimmerman’s finding suggested that the hands of trained healers emit pulsed magnetic fields in precisely the frequency range known to promote tissue healing. This does not prove that Therapeutic Touch works through this mechanism — but it provides a plausible, physically measurable candidate mechanism that does not require any new physics.

The implication is profound: what healers call “energy” may be a real, measurable electromagnetic signal, emitted at biologically active frequencies, and detectable by the most sensitive magnetic instruments available.

Seto’s Confirmation: Large Biomagnetic Emissions from Qi Gong Practitioners

Zimmerman’s findings were substantially confirmed and extended by Akira Seto and colleagues at the Central Research Laboratory of Komatsu Ltd. in Japan. Published in 1992 in the Journal of the International Society of Life Information Science, Seto’s study measured the magnetic field from the palms of practitioners of various healing arts, including Qi Gong, Yoga, and Zen meditation.

Seto’s protocol was meticulous. Using a highly sensitive magnetometer (a fluxgate magnetometer rather than a SQUID, but still capable of detecting fields in the picotesla range), he measured the magnetic field from the palms of three groups:

Control subjects. Ordinary individuals with no healing training showed palm magnetic emissions of approximately 1 femtotesla — essentially at the noise floor.

Practitioners at rest. Healing practitioners who were not actively performing their practice showed slightly elevated but still minimal emissions.

Practitioners during practice. During active practice — Qi Gong, yoga, or meditation — certain practitioners produced magnetic fields from their palms reaching 1-10 milligauss (0.1-1 microtesla). This is an extraordinary finding — these emissions were approximately 1,000 times stronger than the heart’s magnetic field and 1,000,000 times stronger than the baseline emissions from ordinary hands.

Seto noted that not all practitioners produced these large emissions, and that the emissions seemed to correlate with the practitioner’s subjective experience of “energy flow” and their years of practice. He also noted that the emissions were pulsatile, occurring in bursts at frequencies in the low-frequency range (below 30 Hz).

The Heart’s Magnetic Field: A Three-Foot Broadcast

While the hands of healers represent a special case, the most consistently measurable biomagnetic field in every human is the heart’s magnetic field. And its characteristics are extraordinary.

The heart generates the largest electromagnetic field in the body. Using SQUID magnetometers, researchers have measured the heart’s magnetic field at distances of up to three feet (approximately one meter) from the body. The HeartMath Institute, using a custom-built 16-channel magnetometer array, has demonstrated that the heart’s field is roughly 5,000 times stronger than the brain’s magnetic field and can be detected several feet away.

But the most significant finding is not the field’s strength — it is its information content.

The Heart’s Magnetic Field Carries Emotional Information

Research by Rollin McCraty and colleagues at the HeartMath Institute has demonstrated that the heart’s magnetic field contains information about the person’s emotional state — and that this information can be detected by others.

In a series of experiments, McCraty measured the magnetic field of one person’s heart and looked for its signal in the brainwave (EEG) recording of another person sitting nearby. The findings:

• When two people sat within conversational distance (about three to four feet), the heartbeat signal of one person could be detected in the EEG of the other person.
• The effect was strongest when the two people were in physical contact (holding hands), but was detectable even without contact.
• The coherence of the heart rhythm mattered: when one person was in a state of heart coherence (a smooth, sine-wave-like HRV pattern associated with positive emotions), the signal transfer to the other person’s EEG was stronger and more consistent.

This finding provides a measurable, physical mechanism for what people experience as “sensing someone’s energy” or “feeling the vibe” of another person. The heart’s electromagnetic field literally broadcasts your emotional state into the space around you, and other people’s nervous systems detect and respond to that broadcast — measurably, in their brainwave patterns.

Magnetoencephalography: Mapping the Brain’s Magnetic Whisper

While the heart shouts electromagnetically, the brain whispers. But SQUID magnetometry has become sophisticated enough to capture that whisper in exquisite detail.

Magnetoencephalography (MEG) uses arrays of hundreds of SQUID sensors arranged in a helmet-shaped array around the head. Modern MEG systems contain 300 or more sensors, each cooled to liquid helium temperature, collectively mapping the brain’s magnetic field with millisecond temporal resolution and millimeter spatial resolution.

MEG has become a critical tool for consciousness research because it can track the brain’s magnetic activity in real time, without the distortions inherent in EEG.

MEG and Meditation Research

Several landmark studies have used MEG to study brain activity during meditation:

Gamma synchrony in long-term meditators. Antoine Lutz, Richard Davidson, and colleagues at the University of Wisconsin used both EEG and MEG to study Tibetan Buddhist monks with 10,000 to 50,000 hours of meditation experience. The MEG data confirmed what EEG had suggested: these monks produced extraordinary levels of gamma-band (25-42 Hz) synchrony during compassion meditation — levels that had never been observed in any other context. The magnetic source localization provided by MEG showed that this gamma activity originated from distributed cortical networks, not a single brain region, suggesting a global integration of neural processing.

Theta activity in mindfulness meditation. MEG studies of mindfulness practitioners have revealed increased frontal midline theta activity (4-8 Hz) during meditation, with source localization pointing to the anterior cingulate cortex and medial prefrontal cortex — regions associated with attention monitoring and emotional regulation.

Alpha blocking and default mode network. MEG has been used to map the magnetic correlates of default mode network (DMN) deactivation during meditation. The DMN, often associated with self-referential thought and the “narrative self,” shows characteristic alpha-band (8-13 Hz) activity at rest. During focused meditation, MEG reveals reduced alpha power in DMN regions, consistent with the subjective experience of reduced self-referential thinking.

The DC Magnetic Field: Becker’s Forgotten Discovery

The biomagnetic fields measured by SQUID magnetometers are alternating fields — they oscillate at specific frequencies corresponding to the heart’s rhythm, the brain’s waves, or the healer’s pulsatile emissions. But there is another component of the body’s magnetic field that receives far less attention: the direct current (DC) component.

Robert O. Becker, an orthopedic surgeon at the Syracuse VA Hospital, spent decades studying the body’s DC electrical system — a system separate from the alternating-current (AC) signals of the nervous system. Becker found that the body maintains a steady-state DC electrical field that he called the “current of injury” system, and which he later recognized as a global regulatory system.

Becker’s key findings, published in his landmark books The Body Electric (1985) and Cross Currents (1990), included:

• Regeneration currents. When a salamander loses a limb, a specific pattern of DC current appears at the wound site, guiding the regeneration of the lost tissue. Becker showed that by manipulating these currents artificially, he could induce partial regeneration in frogs (which do not normally regenerate) and accelerate bone healing in humans.
• Perineural DC system. The glial cells (Schwann cells and satellite cells) that surround nerve fibers constitute a separate conducting system — the perineural system — that carries DC signals. This system operates in parallel with the nerve impulse system but carries a different type of information: analog, continuous, and global rather than digital, pulsed, and local.
• Magnetic field effects. The DC currents in the body produce corresponding DC magnetic fields. Becker demonstrated that external DC and low-frequency magnetic fields could influence biological processes including bone healing, nerve regeneration, and tumor growth.

Becker’s work was largely ignored by mainstream medicine during his lifetime, but his findings about DC currents and bone healing laid the groundwork for modern PEMF therapy. His concept of the perineural DC system — a body-wide analog communication system operating alongside the neural impulse system — anticipates many aspects of current biofield research.

The relevance to SQUID magnetometry is this: the biomagnetic fields we measure are the AC component of a larger electromagnetic system that includes both alternating and direct current components, operating at multiple scales from cellular to organismal. We are measuring the overtones while the fundamental tone — the DC field — remains largely unexplored by modern instruments.

Harold Saxton Burr: The L-Fields

Decades before Becker, another researcher had mapped the body’s electromagnetic fields with remarkable thoroughness. Harold Saxton Burr, a neuroanatomist at Yale University, spent over 30 years (1930s-1960s) measuring what he called “L-fields” — electrodynamic fields of life.

Using sensitive voltmeters, Burr measured the voltage gradients on the surface of trees, plants, salamanders, frogs, and humans. His findings, published in over 90 peer-reviewed papers, included:

• Trees maintained stable voltage gradients that fluctuated with lunar cycles, sunspot activity, and thunderstorms.
• Frog eggs showed specific voltage patterns that predicted the future location of the nervous system before any physical differentiation had occurred.
• Women showed cyclical voltage changes correlated with the menstrual cycle, with a sharp voltage spike at the time of ovulation — accurate enough to predict ovulation timing.
• Cancer tissue showed measurable voltage differences compared to healthy tissue, detectable before clinical symptoms appeared.
• Wound healing progressed along predictable voltage gradients, with the wound site maintaining a negative potential relative to surrounding tissue.

Burr argued that the L-field was not merely a byproduct of biological activity but an organizing field — a morphogenetic field that guided the development and maintenance of biological form. He wrote: “The pattern or organization of any biological system is established by a complex electro-dynamic field, which is in part determined by its atomic physicochemical components and which in part determines the behavior and orientation of those components.”

This is a radical claim, and it remains unproven in its strong form. But Burr’s measurements themselves — the voltage patterns, their correlations with physiological states, their predictive power — have been confirmed by subsequent researchers and form a foundational layer of biofield science.

Measuring the Unmeasurable: Technical Challenges

SQUID magnetometry of biological systems faces formidable technical challenges that shape what can and cannot be measured:

Magnetic Shielding

The Earth’s magnetic field is approximately 50 microtesla. The heart’s magnetic field at chest distance is approximately 50 picotesla — a million times weaker. The brain’s magnetic field is another thousand times weaker still. To measure these signals, you must either subtract the Earth’s field with extraordinary precision or physically block it.

Modern magnetically shielded rooms (MSRs) use multiple layers of high-permeability mu-metal (a nickel-iron alloy) to attenuate external magnetic fields by factors of 1,000 to 1,000,000. The most sophisticated MSRs also use active compensation coils — electromagnets that dynamically cancel residual fields detected by reference sensors.

These rooms are expensive — $500,000 to $2,000,000 or more — and are a major barrier to widespread biomagnetic research.

Cryogenics

Conventional SQUID sensors operate at 4.2 Kelvin (liquid helium temperature), requiring bulky, expensive cryogenic dewars that must be regularly refilled. A typical MEG system consumes 100-200 liters of liquid helium per week. This has restricted SQUID-based biomagnetic measurement to well-funded research institutions and hospitals.

High-temperature SQUID sensors, operating at 77 Kelvin (liquid nitrogen temperature), have been developed but are generally less sensitive than their low-temperature counterparts.

Signal Processing

The biomagnetic signal of interest is always embedded in noise — environmental magnetic noise, physiological noise from other body sources, and sensor noise. Extracting the signal requires sophisticated signal processing: adaptive filtering, spatial filtering (beamforming), independent component analysis, and other techniques borrowed from radar and sonar engineering.

The analogy to signal processing is exact. The biofield researcher faces the same challenge as the submarine sonar operator: detecting a faint signal in a noisy ocean. The tools are similar — matched filters, spectral analysis, array processing — and the skills required are the same engineering skills.

The Bridge Between Physics and Healing

The SQUID magnetometer has done something that no other instrument in the history of science has accomplished: it has provided direct, physical, quantitative measurements of the electromagnetic fields that healers and mystics have described for millennia.

The heart broadcasts an electromagnetic field that carries emotional information and can be detected by others. The brain produces magnetic fields that map consciousness states with exquisite precision. The hands of trained healers emit pulsed magnetic fields at frequencies known to promote tissue healing. The body maintains DC electromagnetic fields that correlate with health, disease, and regenerative capacity.

None of this requires new physics. All of it follows directly from Maxwell’s equations, the quantum mechanics of superconductivity, and the known bioelectric properties of living tissue. The fields are real. The measurements are reproducible. The correlations with health and consciousness states are consistent.

What remains unresolved is the question of causation versus correlation. Does the heart’s electromagnetic field directly influence other people’s brainwaves, or is it merely a measurable correlate of some other mechanism (like subtle body language or pheromones)? Do the magnetic emissions from healers’ hands actually promote tissue healing, or are they an epiphenomenon of whatever the healer is really doing?

These are scientific questions with scientific answers — answers that will come from more and better SQUID measurements, from intervention studies, from careful controls, and from the integration of biomagnetic data with other biofield measurements.

The SQUID magnetometer is the quietest instrument ever built. And in its silence, it is hearing something that has always been there — the electromagnetic voice of the living body, speaking in the language of fields and frequencies, broadcasting its state to everything around it.

The mystics were right that we are beings of energy and light. The physicists were right that everything measurable follows known laws. The SQUID sits at the intersection of these two truths, listening.

References and Further Reading

Zimmerman, J. T. (1990). New technologies detect effects of healing hands. Brain/Mind Bulletin, 16(2), 20-23.

Seto, A., Kusaka, C., Nakazato, S., et al. (1992). Detection of extraordinary large biomagnetic field strength from human hand during external Qi emission. Acupuncture & Electro-Therapeutics Research, 17(2), 75-94.

McCraty, R. (2015). Science of the Heart, Volume 2: Exploring the Role of the Heart in Human Performance. HeartMath Institute.

Cohen, D. (1968). Magnetoencephalography: Evidence of magnetic fields produced by alpha-rhythm currents. Science, 161(3843), 784-786.

Lutz, A., Greischar, L. L., Rawlings, N. B., Ricard, M., & Davidson, R. J. (2004). Long-term meditators self-induce high-amplitude gamma synchrony during mental practice. Proceedings of the National Academy of Sciences, 101(46), 16369-16373.

Becker, R. O., & Selden, G. (1985). The Body Electric: Electromagnetism and the Foundation of Life. William Morrow.

Becker, R. O. (1990). Cross Currents: The Perils of Electropollution, The Promise of Electromedicine. Tarcher.

Burr, H. S. (1972). Blueprint for Immortality: The Electric Patterns of Life. Neville Spearman.

Hämäläinen, M., Hari, R., Ilmoniemi, R. J., Knuutila, J., & Lounasmaa, O. V. (1993). Magnetoencephalography — theory, instrumentation, and applications to noninvasive studies of the working human brain. Reviews of Modern Physics, 65(2), 413-497.

Oschman, J. L. (2000). Energy Medicine: The Scientific Basis. Churchill Livingstone.