Abstract: One of the main reasons why the existence of the effect of the influence of space weather on living organisms has caused skepticism among representatives of academic science for many years is the insufficient, according to the criteria of modern physics, the stability of the reproduction of the heliobiological effect. Signs of instability are the strong variability of the characteristics of the results obtained: amplitude, time lag, and even the sign of the effect.
The paper formulates and substantiates the hypothesis that this instability is primarily due to methodological reasons: existing approaches, traditional for physics and biology of the XX century, are poorly suited for the study of a complex multilevel system of solar-biospheric connections.
Using concrete examples, it is shown that new methodological principles, both already included in heliobiological research in the last 10 years, and newly formulated in this work, can significantly reduce the percentage of unexplained non-reproducible results.
It is shown that it is necessary to take into account such specific features of the heliobiological effect as the individual nature of the reaction to space weather, the dependence of the effect on the phase of the cycle of solar and geomagnetic activity and on the sampling scale of experimental data, taking into account the possible contribution of meteorological factors, as well as the existence of different types of response of the biological system at different time scales.

Abstract: This article discusses the main achievements in recent years in the study of the biological effects of weak and super weak low-frequency magnetic fields, either variable or combined with constant ones. Considered are neutrophil granulocytes activated by chemical stimulants or intact when the magnetic fields affect isolated cells, blood, and whole organisms. The methods include recording changes in ROS concentration levels (the most noticeable effect of exposure to a weak magnetic field), priming index, calcium homeostasis, proliferative activity, immune status, and the influence of various chemical agents on these indicators. The leading methods in this field are fluorescence spectrometry and chemiluminescence analysis. The experimental results indicate the biological effectiveness of this physical factor, the specific effect of which depends on the type of biosystem, its functional status, the environment, and the parameters of the fields themselves. The data obtained can have applied significance in magnetotherapy, immune response optimization in various diseases, acceleration of tissue regeneration and repair, and increasing the body's resistance to infections. They also can have academic significance as they help identify the primary field acceptors and magnetic targets and their localization in the cell, study relationships with signal cascades, build models of biological signal amplification pathways, and find biologically significant frequencies and field amplitudes.