ABSTRACT
The human brain seems to be able to respond to low-level extremely low-frequency electromagnetic fields. Controlled laboratory studies of human sleep under exposure to such fields are scarce, especially on the effects of 1 Hz – 16 Hz fields overlapping with the frequencies of the electroencephalographic (EEG) signal (e.g., delta, theta, alpha, and sigma activities). In a double-blind placebo-controlled study, we examined the effects of exposure to low-level electromagnetic fields of frequencies 2 Hz and 8 Hz on the EEG power density spectra in the range from 1 Hz to 16 Hz and sleep structure. Sleep of 14 young healthy volunteers was polysomnographically recorded during three 50-min afternoon naps (either without exposure or with 2 Hz/0.004 μT or 8 Hz/0.004 μT electromagnetic field). During the first 30 min of a nap the sham, 2 Hz or 8 Hz/0.004 μT exposures had the same effect. For the remaining 20 min, amount of stage 3 sleep and powers in 1 Hz-8 Hz range continued to build up under the 8 Hz/0.004μT and, especially, under the 2 Hz/0.004 μT exposure, whereas they did not change in the sham condition. Therefore, the low-level 2 Hz electromagnetic fields might stimulate deep sleep in the afternoon nap.
Acknowledgments
The authors are very grateful to Ekaterina V. Tiunova and Irina A. Piletskaya form the Moscow State Pedagogical University, Moscow, Russia for their help in conducting the nap study. They also thank the unpaid volunteers for their participation in the study.
Disclosure statement
The authors have no conflicts of interest to declare.
Ethical approval
All procedures performed in the studies were in accordance with the ethical standards of the 1964 Helsinki declaration and its later amendments or comparable ethical standards. The protocols of the studies were approved by the Ethics Committee of the Institutes (#2 from 03.06.2019). Each participant of the experimental study was informed in detail about all procedures and gave his/her written consent.