Sleep latency in poor nappers under exposure to weak 2-Hz and 8-Hz electromagnetic fields

It was hypothesized that human sleep might respond to the fields emitted by such natural sources as magnetic activity of the sun and the earth's magnetic fields. However, the experiments aimed on testing this hypothesis remain scarce. Previously, we found an increase in the amounts of stages N2 or N3 during napping of good sleepers under exposure to low-level (0.004 mu T) electromagnetic fields of frequencies 1 Hz or 2 Hz. It remains unexplored whether these fields might additionally decrease latency to stage N1. In this study, we selected 13 people with falling asleep problems to examine the effects of low-level electromagnetic fields on sleep latency. Sleep of these study participants was polysomnographically recorded during three 50-min afternoon napping attempts, either with exposure to either 2 Hz/0.004 mu T or 8 Hz/0.004 mu T electromagnetic fields or without exposure. We did not find that the sham exposure differed from the 2 Hz and 8 Hz exposures in latency to N1, while latency to N2 after the sham exposure was even shorter than after either the 2 Hz or 8 Hz exposure. We concluded that, although the effects of tested fields might be beneficial for sleep intensity (e.g., due to prolongation of N3), they might not be additionally effective against the falling asleep problems.