Some studies have shown that people living near a mobile phone base station may report sleep disturbances and discomfort. Using a rat model, we have previously shown that chronic exposure to a low-intensity radiofrequency electromagnetic field (RF-EMF) was associated with paradoxical sleep (PS) fragmentation and greater vasomotor tone in the tail. Here, we sought to establish whether sleep disturbances might result from the disturbance of thermoregulatory processes by a RF-EMF. We recorded thermal preference and sleep stage distribution in 18 young male Wistar rats. Nine animals were exposed to a low-intensity RF-EMF (900 MHz, 1 V.m⁻¹) for five weeks and nine served as non-exposed controls. Thermal preference was assessed in an experimental chamber comprising three interconnected compartments, in which the air temperatures (T_a) were set to 24°C, 28°C and 31°C. Sleep and tail skin temperature were also recorded. Our results indicated that relative to control group, exposure to RF-EMF at 31°C was associated with a significantly lower tail skin temperature (−1.6°C) which confirmed previous data. During the light period, the exposed group preferred to sleep at T_a = 31°C and the controls preferred T_a = 28°C. The mean sleep duration in exposed group was significantly greater (by 15.5%) than in control group (due in turn to a significantly greater amount of slow wave sleep (SWS, +14.6%). Similarly, frequency of SWS was greater in exposed group (by 4.9 episodes.h⁻¹). The PS did not differ significantly between the two groups. During the dark period, there were no significant intergroup differences. We conclude that RF-EMF exposure induced a shift in thermal preference towards higher temperatures. The shift in preferred temperature might result from a cold thermal sensation. The change in sleep stage distribution may involve signals from thermoreceptors in the skin. Modulation of SWS may be a protective adaptation in response to RF-EMF exposure.

Environmental Health Perspectives is an Open Access journal published by the National Institute of Environmental Health Sciences. Environmental Health Perspectives is an Open Access journal published by the National Institute of Environmental Health Sciences.

Recent studies have shed light on the effects of low-intensity radiofrequency (RF) fields on thermoregulation and adipose tissue metabolism. The present study aims to further explore these effects by analyzing the expression of thermoregulatory genes and investigating the involvement of mitochondria in adipose tissue metabolism. Male mice (n = 36 C57BL/6J) were assigned to either exposed or control groups. The exposed groups were subjected to RF fields at 900 MHz, with specific absorption rates (SAR) of 0.1 W/kg or 0.4 W/kg, either for three or seven consecutive days. The findings indicate that RF exposure leads to changes in adipose tissue markers, with some effects being dose-dependent and time-dependent. In brown adipose tissue (BAT), after 3 days of RF exposure, thermogenesis is reduced, mitochondrial activity in BAT decreases, and an increase in gene expression, responsible for balancing the regulatory and damaging effects of reactive oxygen species (ROS), was observed. This effect was partially compensated after 7 days of exposure. In white adipose tissue (WAT), RF exposure results in reduced fatty acid oxidation, impaired energy production, and hindered adipocyte differentiation. Notably, no effects of RF on mitochondrial biogenesis in WAT were observed. These findings contribute to understanding the effects of RF exposure on adipose tissue metabolism and thermoregulation, highlighting dose-dependent and time-dependent responses.

The widespread use of wireless technologies has raised public health concerns about the biological effects of radiofrequency (RF) exposure. Children have a higher specific absorption rate (SAR) of radiation energy compared to adults. Furthermore, brown adipose tissue (BAT) is more prevalent in infants and tends to decrease with age. Previous animal studies demonstrated a cold sensation in rats exposed to 900 MHz (second generation, 2G). UCP1-dependent thermogenesis and BAT hyperplasia are two fundamental adaptive mechanisms initiated in response to cold. This study investigated the impact of short-term exposure to 2G and fifth generation (5G) on key thermogenic and adipogenic markers related to these mechanisms while considering age and exposure duration. Juvenile and young adult Wistar rats were randomized into three subgroups: a 5G group (3.5 GHz), 2G group (900 MHz), and a control group (SHAM). They were exposed to their respective continuous-wave RF signals for 1 or 2 weeks at an intensity of 1.5 V/m, with two exposure sessions of 1 h per day. After the exposure period, a RT-qPCR was carried out to evaluate the genetic markers involved in BAT thermogenesis and adipogenesis. Two adipogenic biomarkers were affected; a fold change reduction of 49% and 32% was detected for PRDM16 (p = 0.016) and C/EBP β (p = 0.0002), respectively, after 5G exposure, regardless of age and exposure duration. No significant RF effect was found on UCP1-dependent thermogenesis at a transcriptional level. These findings suggest that exposure to a 5G radiofrequency may partially disrupt brown adipocyte differentiation and thermogenic function by downregulating PRDM16 and C/EBP β, possibly leading to higher cold sensitivity.