Magnetobiology is one of the areas of radiobiology of non-ionizing radiation ; A branch of biophysics that studies the biological effects of weak low-frequency magnetic fields that do not cause tissue heating. Corresponds to the somewhat more general English term bioelectromagnetics , which should not be confused with the term bioelectromagnetism . Magnetobiological effects are characterized by properties that clearly distinguish them from thermal effects - they are often observed only in some frequency and amplitude ranges of variable magnetic fields, depend on the simultaneous presence of a constant magnetic or electric field, on the polarization of the field.
In a more general sense, any biological effects caused by a change in the magnetic conditions at the location of the organism are referred to magnetobiology. However, the problem, mainly physical, is made up of the biological effects of precisely weak, approximately less than 0.1 mT, low-frequency, from 100 Hz and less, magnetic fields. Such effects seem paradoxical: the energy quantum of an alternating electromagnetic field is many orders of magnitude smaller than the energy scale of an elementary act of a chemical reaction, and the field intensity is insufficient for any significant heating of the tissues. A striking magnetobiological effect of quasistatic magnetic fields is magnetic navigation (other than magnetic orientation) carried out by migrating animals, see, for example, Bird migration section Orientation and navigation, Magnetite section Biological occurrences, Sense section Direction, Homing Pigeon section Navigation, Natal homing section Geomagnetic Imprints. It has been established that animal migration to seasonal habitats occurs in many cases through the reception of small variations in the geomagnetic field of the order of tens of nT.
Content
Reproducibility
It should be noted the specific nature of the reproducibility of the results of magnetobiological experiments. Up to a quarter of works on magnetobiology report the impossibility of reproducing effects. In most cases, the experimenters needed a focused search for relatively rare combinations of electromagnetic and physiological conditions that ensure the observation of the effect. Many of the results of magnetobiology have not yet been confirmed by studies of independent laboratories.
EM safety standards
The practical significance of magnetobiology is due to the increasing level of background electromagnetic exposure of the population. Some electromagnetic fields during chronic exposure are unsafe for human health and are no less significant factor than temperature, pressure and humidity. The World Health Organization considers elevated levels of EMF in the workplace as a stress factor. Existing standards of electromagnetic safety, developed by both national and international organizations, for some frequency ranges of the electromagnetic field differ by tens and hundreds of times. This indicates a lack of scientific research in the field of magnetobiology and electromobiology. Currently, most standards only consider the biological effects of heating and electrochemical reactions due to induced currents.
Medical Applications
On the other hand, methods of therapeutic application of relatively weak electromagnetic fields are developing. These methods have not received clinical evidence in accordance with accepted standards of evidence-based medicine. Some organizations consider this practice to be pseudoscientific .
The Possible Nature of Effects
In magnetobiology there is a significant lag in theory from experiment. The physical nature of the phenomenon is still unclear, despite the many observational and experimental data. Often discuss the following alleged causes of magnetobiological phenomena:
- crystallization in the tissues of the body of iron-containing magnetic nanoparticles ,
- the dependence of some biochemical reactions involving pairs of free radicals on the magnitude of the magnetic field,
- the possible existence of long-lived rotational states of certain molecules inside protein structures,
- change in the properties of liquid water in a magnetic field.
An explanation of the physical nature of the biological effects of weak magnetic fields is a fundamental scientific problem.
Literature
- Presman A.S. Electromagnetic fields and wildlife. - M .: Nauka, 1968 .-- 288 p.
- Kholodov Yu.A., Lebedeva HH Reactions of the human nervous system to electromagnetic fields, M .: Nauka, 1992. - 136 p.
- Bingi V.N., Savin A.V. Physical problems of the action of weak magnetic fields on biological systems . // Usp. - 2003. - T.173. - Number 3. - S. 265-300.
- Binhi VN Magnetobiology: Underlying Physical Problems . - San Diego: Academic Press, 2002 .-- 473 p. - ISBN 0-12-100071-0
- Breus T.K., Rapoport S.I. Magnetic storms: biomedical and geophysical aspects. - M.: Soviet Sport, 2003 .-- 192 p. - ISBN 5-85009-861-5
- Gurfinkel Yu.I. Coronary heart disease and solar activity. - M .: IICC "Elf-3", 2004. - 170 p. - ISBN 5-88982-031-1
- Wiltschko R., Schiffner I., Wiltschko W. A strong magnetic anomaly affects pigeon navigation. The Journal of Experimental Biology, 212, 2983-2990, 2009.
- Bingi V.N. Principles of electromagnetic biophysics . - M .: FIZMATLIT, 2011 .-- 592 p. - ISBN 978-5-9221-1333-5
Specialized Scientific Journals
Links
- Transcranial magnetic stimulation
- Magnetoreception