Sleep with an exposure of radiofrequency electromagnetic radiation in growing organisms
Résumé
Disturbances of sleep by radiofrequency electromagnetic radiation (RF-EMR) emitted by mobile phone base stations type GSM are not well-established. This may be explained by the fact that this environmental factor is not strong enough to be significant. Additional stress (e.g. thermal stress) could increase adverse RF-effects on sleep. However, studies are usually carried out in adults exposed to thermoneutrality (even though not strictly controlled). Moreover, there is a lack of information concerning growing organisms for which sleep is particularly important since it promotes cerebral and body restitutions. In this study, it is held that RF-EMR exposition could potentiate sleep disturbances through interaction with thermal stress in juvenile rats. 13 Wistar rats (3 weeks-old) exposed to RF-EMR during 5 weeks were compared to a non exposed control group (n=11). One week after surgery, sleep was measured on different days (00-06 pm) at thermoneutrality (environmental temperature: 24+-1°C) and in a warm environment (31+-1°C), combined or not with RF exposure. Sleep was visually scored in 30 second-periods in Wakefulness (W), Slow Wave (SWS) and Paradoxical Sleep (PS). The total durations of sleep stages, the mean durations and the frequencies of the episodes were analyzed with ANOVA. RF exposure did not modify total sleep stage and wakefulness durations. However, when compared to non exposed group, significant RF-effects were found at 31°C but not at 24°C: W and SWS episodes were longer but less frequent (W: 7.0 vs 5.0 min, 0.9 vs 1.8 episodes.h-1 ; SWS: 3.2 vs 2.8 min, 12.1 vs 14.2 episodes.h-1 ; always p<0.01). The reverse was observed for PS (1.7 vs 2.1min ; 5.2 vs 3.8 episodes.h-1). RF-EMR-effect on sleep is found when this exposure is associated with a thermal stress. This observation strongly suggests that RF-EMR exposure modifies the sleep structure by disturbing thermoregulatory processes