EHS debate on BRHP: Denis Henshaw responds to Martin Röösli

Last night I received message from Denis L. Henshaw, with a response to Martin Röösli.


The opinion of Denis L. Henshaw

(includes three illustrative slides in pdf format)

One form of EHS which must surely be as old as mankind itself is the example of acute health effects associated with Geomagnetic (GM) storms [Note 1]. Such storms, arise from explosive events on the sun’s surface sending streams of charged particles towards the Earth, inducing small fluctuations in the Earth’s otherwise static magnetic field (MF) – see slide 1 of 3 (Geomagnetic Storms and Electrosensitivity May 2020)

The GM storms of interest are those involving MF fluctuations of around 100 nT over a 3‑hour period, lasting 1–5 days, superimposed on the static GM-field of 50,000 nT (50 uT) in the UK.

Slide 2 lists some of the studies of acute health effects associated with these storms, for example, increase in depressive illnesses, melatonin disruption, heart rate variability and blood pressure changes. Obviously, there is no issue with blinding in these studies. People generally have no idea that there has been a GM storm, so this is a “natural”, experiment. Also, the studies are disparate, carried out by a variety of clinicians and researchers over many decades across the world.

As a general hypothesis: “Are there acute health effects associated with GM storms”? I would say yes, there is proof beyond all reasonable doubt.

Two feature of GM storms in relation to acute effects in humans are of interest. First is the very low level of apparent sensing – around 100 nT. We know that all forms of life can sense magnetic fields, including humans, albeit unconsciously (see Wang et al 2019) [Note 2]. The detection threshold for the magnetic compass in the garden warbler is estimated to be a mere 2–3 nT (Pakhomov et al 2017).

The second feature is the ultra-low frequency, MF fluctuations over a 3-hour period. However, as seen in slide 3, the structure of the GM storm signal shows some similarity with other time-varying MFs across a large frequency range. Interesting, avian migration and/or magnetic orientation has been reported to be disrupted both by GM storms and by anthropogenic electromagnetic noise (Schiffner and Wiltschko 2011; Engels et al 2014; see also Wiltschko et al 2009).

So how may this relate to EHS linked to RF EMFs? I offer a possible mechanistic and an intuitive idea.

There is strong evidence that the animal compass functions by the action of the Radical Pair Mechanism, RPM via cryptochrome protein molecules in the eye. Cryptochromes are best known for their control of circadian rhythms, human cryptochromes have been shown to be magneto-sensitive and to release reactive oxygen species (ROS) by the action of MFs – Foley et al 2011; Sherrard et al 2018). The RPM is the process by which low intensity magnetic fields can alter the spin state of pairs of free radicals from the so-called short-lived singlet, S-state (nano-second lifetime) to the so-called longer-lived (micro-second lifetime) triplet, T-state making them more available to cause biological damage [Note 3] .

Experimental tests in birds and other species have used RF EMFs in the MHz range to disrupt magnetic orientation by interfering with the proposed S-T interconversion process (Ritz et al 2004; Vacha et al 2009; Pakhomov et al 2017).

For my intuitive idea, I note Martin Röösli’s comment: “A substantial proportion of EHS individuals reports to react within minutes to EMF exposure…”.

So, is EHS any different to arachnophobia? If a sufferer sees a spider running across the floor, they respond with fear immediately. There is no physical interaction here, merely a response in the brain to what is detected by the eye. Could it be that EHS sufferers, like all of us, detect magnetic fields but the brain simply cannot tolerate the types of signals seen in slide 3, whether ultra-low or ultra-high frequency? Can this in turn lead to the acute health effects reported from GM-storms and RF EMF alike?

A possible test of this idea is to ask EHS sufferers to keep a diary and log when they suffer symptoms without an apparent explanation. Later, this could be matched against GM-storm events to see if there was any correlation. Such a study could readily be double-blinded.

Alternatively, could EHS sufferers take part in an experiment where the provocation is a simulated GM-storm, at the same time screening from electrosmog (see Engels et a 2014)?

Finally, a note about biomarkers:

Are we looking in the right place? The left hand of left-handed people looks no different to the left hand of right-handed people – why? – because left-handedness is not in the hand, it is in the brain. And yet, there is a clear visible marker in left-handed people: they are left-handed!


  • [1]. I picked this off Google: “What are the effects of geomagnetic storms? It has long been established that magnetic storms not only affect the performance of equipment, upset radio communications, blackout radars, and disrupt radio navigation systems but also endanger living organisms. They change the blood flow, especially in capillaries, affect blood pressure, and boost adrenalin.” While not peer-reviewed it does reflect accepted knowledge.
  • [2]. Just as humans need two quantities to navigate the Earth, latitude and longitude, animal navigation in the GM-field requires intensity and direction. An RPM-based compass provides MF direction, but evidence suggest that intensity is provided by magnetic particles in the body (Wiltschko and Wiltschko 2009). The recent evidence for human magnetoreception, suggests reception by magnetic particles in the body (Wang et al 2019).
  • [3]. It is also worth noting that the RPM operates at energies some ~107 below thermal levels.

References cited:

  • Engels S, Schneider N-L, Lefeldt N, Hein CM, Zapka M, Michalik A, Elbers D, Kittel A, Hore PJ, Mouritsen M. 2014. Anthropogenic electromagnetic noise disrupts magnetic compass orientation in a migratory bird. Nature 509:353–356. doi:10.1038/nature13290
  • Foley LE, Gegear1 RJ, Reppert SM. 2011. Human cryptochrome exhibits light-dependent magnetosensitivity. Nature Comm. DOI: 10.1038/ncomms1364
  • Pakhomov A, Bojarinova J, Cherbunin R, Chetverikova R, Grigoryev PS, Kavokin K, Kobylkov D, Lubkovskaja R, Chernetsov N. 2017. Very weak oscillating magnetic field disrupts the magnetic compass of songbird migrants. J. R. Soc. Interface 14: 20170364.
  • Ritz T, Thalau P, Phillips JB, Wiltschko R, Wiltschko W. 2004. Resonance effects indicate a radical-pair mechanism for avian magnetic compass. Nature 429:177-180.
  • Schiffner I, Wiltschko R. 2011. Temporal fluctuations of the geomagnetic field affect pigeons’ entire homing flight. J Comp Physiol A DOI 10.1007/s00359-011-0640-y
  • Sherrard RM, Morellini N, Jourdan N, El-Esawi M, Arthaut L-D, Niessner C, Rouyer F, Klarsfeld A, Doulazmi M, Witczak J, d’Harlingue A, Mariani J, Mclure I, Martino CF, Ahmad M. 2018. Low-intensity electromagnetic fields induce human cryptochrome to modulate intracellular reactive oxygen species. PLoS Biol 16(10): e2006229.
  • Vacha M, Puzova T and Kvicalova M, 2009.  Radio frequency magnetic fields disrupt magnetoreception in American cockroach.  The Journal of Experimental Biology, 212:3473-3477.
  • Wang CX, Hilburn IA, Wu D-A, Mizuhara Y, Cousté CP,  Abrahams JNH, Bernstein SE, Matani A, Shimojo S, Kirschvink JL. 2019. Transduction of the Geomagnetic Field as Evidenced from alpha-Band Activity in the Human Brain.
  • Wiltschko R, Schiffner I and Wiltschko W, 2009.  A strong magnetic anomaly affects pigeon navigation.  The Journal of Experimental Biology 212:2983-2990.
  • Wiltschko R., Wiltschko W. 2009. Avian Navigation. The Auk 126(4):717–743.

1 thought on “EHS debate on BRHP: Denis Henshaw responds to Martin Röösli

  1. Did anyone mention the coincidence of sunspots with viral pandemics?

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