Abstract

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A coupling between geomagnetic activity and the human nervous system’s function was identified by virtue of continuous monitoring of heart rate variability (HRV) and the time-varying geomagnetic field over a 31-day period in a group of 10 individuals who went about their normal day-to-day lives.

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A time series correlation analysis identified a response of the group’s autonomic nervous systems to various dynamic changes in the solar, cosmic ray, and ambient magnetic field.

 

Correlation coefficients and p values were calculated between the HRV variables and environmental measures during three distinct time periods of environmental activity.

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There were significant correlations between the group’s HRV and solar wind speed, Kp, Ap, solar radio flux, cosmic ray counts, Schumann resonance power, and the total variations in the magnetic field.

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In addition, the time series data were time synchronized and normalized, after which all circadian rhythms were removed.

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It was found that the participants’ HRV rhythms synchronized across the 31-day period at a period of approximately 2.5 days, even though all participants were in separate locations.

 

Overall, this suggests that daily autonomic nervous system activity not only responds to changes in solar and geomagnetic activity, but is synchronized with the time-varying magnetic fields associated with geomagnetic field-line resonances and Schumann resonances.

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Keywords: heliobiology, geomagnetic field, HRV, Schumann resonance, heart rate variability, solar wind, ANS, autonomic nervous system, cosmic rays, solar radio flux

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1. Introduction

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All biological systems on Earth are exposed to an external and internal environment of fluctuating invisible magnetic fields of a wide range of frequencies [1].

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These fields can affect virtually every cell and circuit to a greater or lesser degree. Numerous physiological rhythms have been shown to be synchronized with solar and geomagnetic activity [2,3,4,5,6].

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Human regulatory systems are designed to adapt to daily and seasonal climatic and geomagnetic variations; however, sharp changes in solar and geomagnetic activity and geomagnetic storms can stress these regulatory systems, resulting in alterations in melatonin/serotonin balance [7,8,9], blood pressure, immune system, reproductive, cardiac, and neurological processes [10,11,12,13].

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Disturbed geomagnetic activity is associated with the intensification of existing diseases, significant increases in myocardial infarction incidence and death, changes in blood flow, aggregation, and coagulation, increased blood pressure, cardiac arrhythmias, and seizures in epileptics [2,3,11,14,15,16,17,18,19,20,21,22].

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During periods of increased solar activity, which peaks every 10.5 to 11 years, the sun emits increased ultraviolet (UV) energy and solar radio flux, which is measured by the 2.8 GHz signal (F10.7) [23,24].

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Although the details of the physiological mechanisms in humans and animals are not yet fully understood, it is apparent that solar and magnetic influences affect a wide range of human health and behavioral processes, with the cardiovascular and nervous systems being the most clearly affected [4,25].

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The application of heart rate variability (HRV) as an indicator of autonomic nervous system (ANS) function and dynamics has greatly increased in recent years in both clinical and research settings [26,27,28,29].

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HRV is the naturally occurring change in the time intervals between adjacent pairs of heartbeats, and reflects the functional status of interdependent regulatory systems that operate on different time scales to adapt to environmental and psychological challenges [30].

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Low levels of age-adjusted HRV indicate chronic stress, pathology, or inadequate functioning in various levels of regulatory control systems in the neuro axis, and is predictive of all-cause mortality [29,31,32].

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Healthy levels of HRV indicate psychological resiliency, behavioral flexibility and capacity to effectively self-regulate and to adapt to changing social or environmental demands [26,33,34], one’s sense of coherence [35], the personality character traits of Self-Directedness [36], and performance on cognitive performance tasks requiring the use of executive functions [29].

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A number of studies have found significant associations between magnetic storms and decreased HRV, suggesting that the cardiovascular system is impacted by geomagnetic disturbances [13,14,37,38,39,40,41,42,43,44].

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Several of these studies found a ~25% reduction in the very low frequency (VLF) rhythm [39,40,41,45], which is most strongly associated with increased health risk [46].

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The low frequency (LF) rhythms were also significantly reduced, while the high frequency (HF) rhythms were not.

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Dimitrova et al., found that during geomagnetic storms, both LF and HF measures as well as the ratio between low and high frequencies tended to be reduced [38].

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Several early studies observed an “anticipatory reaction” in physiological measures that can occur 2 to 3 days prior to the start of magnetic storms.

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There were significant changes in heart rate, HRV, blood pressure, skin conductance, and subjective physiological complaints [6,38,47,48,49,50,51,52].

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This anticipatory affect was first observed by Chizhevsky in the 1920s, prior to the knowledge of high frequency emissions such as X-rays and the gigahertz frequencies (solar radio flux) radiated by the sun.

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He suggested that some unknown radiation from the sun was responsible for this anticipatory effect [48].

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Increased radiations produced by coronal ejections reach the earth in 8 min, while the increased density and speed of the solar wind takes several days to reach the Earth’s magnetosphere, resulting in a magnetic storm, which explains the early observations of an anticipatory effect.

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Stoupel, et al., correlated increased geomagnetic activity combined with high levels of cosmic rays with increases in the number of emergencies and deaths during these periods, including increases in sudden cardiac death and cerebral strokes [53,54].

Considerably less attention has been given to potential links between ultra low frequency (ULF) waves and health or physiological functions.

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The most common source of ultra low frequency waves are field-line resonances, which exhibit the largest amplitudes of the magnetic waves occurring in the magnetosphere [55].

The frequency of these waves depends on the length of the magnetic field lines, the field strength, and the speed and density of the solar wind.

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Waves in the frequency range below 1 hertz are classified with respect to their waveform shape and frequency, where sinusoidal oscillations are called “Pc” (pulsations continuous) and irregular waveforms are defined as “Pi” oscillations (pulsations irregular).

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Each major type is subdivided into frequency regions related to different phenomena. Standing wave field-line oscillations are associated with Pc3 to Pc5 waves in the frequency range between 1 mHz and 100 mHz (periods of 1000 to 10 s).

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Oscillations classified as Pc1 and 2 are traveling waves with frequencies up to 5 Hz, which are typically associated with geomagnetic sub-storms [56].

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Studies have shown that an increase in field-line resonances can affect the human cardiovascular system, likely due to the Pc frequencies overlapping with the rhythms of the autonomic nervous and cardiovascular systems [57].

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Khabarova and Dimitrova also found that the ULF waves between 2–10 mHz had the strongest correlation with increases in blood pressure (0.6) compared to geomagnetic measures (0.3) [6].

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In addition, Zenchenko et al. reported that in two-thirds of their experiments, they found a synchronization between heart rhythms and the ultra-low frequency components (0.5 to 3.0 mHz) of the geomagnetic field [58].

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In the late 1950s, Schumann and Koenig measured a set of frequencies consistent with the mathematical model predicting an earth-ionospheric cavity resonance [59].

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The frequency of the first Schumann resonance (SR), as they are now named, is approximately 7.83 Hz, with a (day/night) variation of about ±0.5 Hz.

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The other SR frequencies are ~14, 20, 26, 33, 39, and 45 Hz, which closely overlap with human brainwaves, such as alpha (8–12 Hz), beta (12–30 Hz), and gamma (30–100 Hz).

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This similarity between the frequencies produced by the brain and the SRs and the tendency of the electroencephalogram rhythms to become synchronous with SR activity was first reported by Koenig [60].

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Pobachenko et al. [61] monitored the SRs and EEGs of 15 individuals over a six week period, and found that variations in the EEG were correlated with changes in the SR across the daily cycle, and the largest correlations between the EEGs and SRs were during periods of higher magnetic activity.

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Persinger et al. have also studied EEG activity and the SR in real-time, and demonstrated that several of the SR frequencies are clearly found in the spectral profiles of human brain activity [62,63].

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In their studies, they found that the power within the EEG spectral profiles had repeated periods of coherence with the first three SR resonance frequencies (7–8 Hz, 13–14 Hz, and 19–20 Hz) in real-time. This suggests that changes in the SR parameters are related to changes in the solar wind, and that solar radiation can affect brain activity, including modulations in cognition and memory consolidation [63].

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Here, we report the results of a study that examined the relationships between solar and geomagnetic activity and human nervous system function as reflected in HRV.

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This study is unique, because it examines changes in a one-month long, continuously recorded HRV data set of 10 participants compared to time-varying changes in solar, local geomagnetic, and Schumann resonance activity.