# Rules of Heliogeomagnetics Diversely Coordinating Biological Rhythms and Promoting Human Health
## 4 Discussion
### Rules of Procedure in Exploring Heliogeomagnetic Effects on Human Physiology
Their effects depend on individuals' sensitivity, health status, and capacity for self-regulation [18; 19; 20; 46]. 7. Magnetic stimulation affect the period and amplitude of the endogenous circadian oscillation. These effects are circadian-phase-dependent, as they vary as a function of the time of day when geomagnetic activity occurs [116; 117]. Increases in the circadian amplitude of HR and HRV suggest that the circadian system can be amplified in association with geomagnetic disturbances. The circadian amplitude of HR was also found to correlate statistically significantly with the 24 h, 12 h, and 8 h amplitudes of the geomagnetic declination index [19; 20; 118]. Changes in the time-varying magnetic field above 80 nT over three hours significantly reduced melatonin concentrations in the body. Reduced concentrations of melatonin may play a role in the development of myocardial ischemia, as melatonin was found to improve myocardial microcirculation under laboratory conditions [119, 120, 121, 122]. * Magnetic fluctuations can affect and enhance HRV indices involved in brain plasticity, psychological resilience, anti-aging effects, and longevity linked to the elevated activity of the brain's DMN with involvement by the circadian clock [19, 20, 52, 112]. Recent evidence suggests that there might be an integrated signaling network in the brain's response to magnetic fluctuations [123, 124, 125, 126, 127]. This network could sense signals from the novel environment and in turn modulate the organism's response, probably in association with the brain's DMN and the circadian intrinsic timekeeping system, including sleep state, autonomic cardiovascular regulatory system, hormone synthesis, immune response, and metabolism. Our studies suggested that humans have a light-dependent magneto reception mechanism as an adapting mechanism involved in adaptive evolution in novel environments. These results led to our hypothesis of a possible involvement of clock genes (_Per2_, _Cry1_ and _Bmal1_) [19, 29, 71, 128]. A possible role of these clock genes (_Per2_, _Cry1_ and _Bmal1_) in the response of cardiovascular variables to geomagnetic fluctuations was also suggested by others [129, 130, 131, 132, 133, 134, 135, 136, 137]. [PERSON] et al. [116] reported that, when low-intensity magnetic stimulation was applied when PER2 expression is maximal, the circadian amplitude of PER2 increased by about 22% in in vitro SCN slices of PERIOD2::LUCIFERASE transgenic \"knock-in\" mice. When applied when PER2 expression was minimal, the circadian amplitude of PER2 expression decreased by about 17%, and the circadian period increased by 2.47 h as compared to controls. Effects of magnetic stimulation thus strongly depends on the circadian phase at which the stimulation is applied [116]. Lastly, a link between geomagnetic activity and human physiology and behavior has been suggested [33, 43, 44, 45, 128], including cardiovascular outcomes [138, 139, 140, 141, 142]. Our study on BP variability in a subarctic area, where the influence of geomagnetic disturbances is felt more strongly, adds to the already available body of evidence.