Complex-spectrum magnetic environment enhances and/or modifies bioeffects of hypokinetic stress condition: An animal study N.A. Temuriantz a , V.S. Martinyuk b , N.G. Ptitsyna c , G. Villoresi d, * , N. Iucci d , Yu. Kopytenko c , M.I. Tyasto c , L.I. Dorman e a Vernadsky Taurida National University, Department of Men & Animal Physiology, Simferopol 95007, Ukraine b Taras Shevchenko National University, Department of Biophysics, Kiev 01033, Ukraine c SPbFIZMIRAN, P.O. Box 188, St. Petersburg 191023, Russia d University ‘‘Roma Tre’’, Via della Vasca Navale 84, Rome 00146, Italy e Tel Aviv University and Israel Space Agency, P.O. Box 2217, Qazrin 12900, Israel Received 17 September 2006; received in revised form 25 June 2007; accepted 26 June 2007 Abstract Monitoring of cardio-vascular function in astronauts on Russian space station Soyuz revealed a decrease of heart rate variability dur- ing periods of increased geomagnetic activity, which is related to increased risk of cardio-vascular disorders. Spaceflight electric and mag- netic environments are characterized by complex combination of static and time-varying components in ULF–ELF (ULF: 0–10 Hz; ELF: 10–1000 Hz) range and by high variability. The objective of this study was to investigate the possible influence of these magnetic fields on rats to understand the pathway regarding functional state of cardio-vascular system. Magnetic field-pattern with variable com- plex spectra in 0–50 Hz frequency range was simulated using three-axial Helmholtz coils and special computer-based equipment. The effect of the magnetic field-exposure on rats was also tested in combination with hypokinetic stress condition, which is typical for manned space missions. It was revealed that variable complex-spectrum magnetic field acts as a weak or moderate stress-like factor and can increase loading for regulatory mechanisms of cardio-vascular system. Various functional shifts can be amplified and modified, when the magnetic field-exposure is combined with hypokinesia. Our results support the idea that variable complex-spectrum MF action involves sympathetic activation, overload in cholesterol transport in blood and also secretor activation of tissue basophyls (mast cells) which can influence the haemodynamics. These functional shifts might lead to increased risk of cardio-vascular diseases. Ó 2007 COSPAR. Published by Elsevier Ltd. All rights reserved. Keywords: Electromagnetic environment; Biological response; Spaceflight conditions; Stress factor; Hypokinesia; Cardio-vascular system 1. Introduction Natural and artificial electromagnetic fields (EMF) are currently viewed as important ecological factors. Space- flight electric and magnetic environments are character- ized by complex combination of static and time-varying components in ultra-low and extremely low frequency range (ULF: 0–10 Hz, ULF: 10–1000 Hz). During last decades it was shown by many authors that ULF–ELF electric and magnetic fields (MF) may produce biological effects and consequently may be a possible source for health problems. Most studies targeted industrial fre- quencies of 50–60 Hz. However, it has been reported that natural and technological MF in wide ULF–ELF fre- quency range also can be linked to different health prob- lems, as increase in incidence of brain cancer, of leukemia, and cardiac diseases as well as to increase in work and traffic accidents (see e.g., Ptitsyna et al., 1995, 1998; Roederer, 1995; Mitsutake et al., 2005 and Refs. therein). 0273-1177/$30 Ó 2007 COSPAR. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.asr.2007.06.052 * Corresponding author. E-mail addresses: timur@crimea.edu (N.A. Temuriantz), mavis @science-center.net (V.S. Martinyuk), Natasha@np5848.spb.edu (N.G. Ptitsyna), giorgiovilloresi@tiscali.it (G. Villoresi), lid@physics.technion. ac.il (L.I. Dorman). www.elsevier.com/locate/asr Advances in Space Research 40 (2007) 1758–1763