Modulation of Zebrafish Heart Rate by Alternating Magnetic Fields with Frequencies Close to Heart Rhythm

Abstract

Overview

Extremely low-frequency magnetic fields (ELF-MF) up to 100 μT exhibit impacts on physiological processes, including heart function. The mechanisms underlying the influence of these fields on fish heart rates remain insufficiently explored. This study hypothesized that direct impact of ELF-MF with a frequency close to heart rate could entrain oscillatory processes responsible for autonomously maintaining heart rhythm in zebrafish embryos.

Methods

• Embryos' heart rates ranged from 1.44 to 3 Hz depending on age.
• ELF-MF with frequencies precisely matched, 10% higher, or lower than the heart rate were applied.
• ELF-MFs with varying amplitudes (by an order of magnitude) were also administered.

Findings

• Almost all tested ELF-MF conditions induced an increased heart rate effect.
• The effect was most pronounced with earlier ontogenesis exposure.
• Fields with frequencies close to heart rate did not entrain cardiac contractions in zebrafish embryos.
• A significant negative correlation between heart rate increase and ELF-MF frequency was observed for ELF-MF with amplitudes of 1.98-3.2 μT and 46.8 μT but not for 30 μT.

Conclusion

Probable molecular mechanisms underlying these effects are discussed in terms of magnetic influence on radical pairs within biochemical oscillating processes. This study provides evidence of ELF-MF’s ability to modulate physiological processes such as heart rate in zebrafish embryos, highlighting the EMF–biological systems connection and its potential health relevance.