Background: Sleep is a biological requirement for human well-being and daily function, which can affect mental and physical health. Using electronic devices can have a significant negative effect on the individual’s sleep. The current study aimed to determine the impact of average minutes of pre-sleep media device use (MDU) on the psychomotor vigilance task (PVT) as one of the measures of vigilance in a sample of Iranian nurses.
Methods: A cross-sectional study was conducted on 200 nurses from Tehran, Iran, who underwent PVT testing. The association between PVT and the average minutes of pre-sleep MDU was evaluated using a multiple regression model and the Spearman correlation coefficient.
Results: After adjusting for age as a confounder, the mean PVT score significantly increased with longer average minutes of pre-sleep MDU (β = 0.85, p < 0.001). Notably, this increase was more substantial among nurses who used media devices for less than 100 minutes (β = 1.53, p < 0.001).
Conclusion: Our findings show that higher durations of pre-sleep MDU were associated with poorer PVT performance among nurses who used media devices for less than 100 minutes and were younger than 35 years old. Thus, it is essential to promote awareness among nurses about the average duration of pre-sleep MDU.

Background: Exposure to extremely low-frequency electromagnetic fields (ELF-EMFs) is pervasive due to modern reliance on electrical and electronic devices. This review examines the potential adverse health effects of ELF-EMFs based on studies published between 2015 and 2023. The investigation spans a range of health outcomes—including neurological, oncological, genetic, and mental health effects—while also highlighting research gaps and regional disparities.
Methods: A systematic review was conducted using the PubMed, Scopus, and Web of Science databases. Eligible studies included original research focused on ELF-EMFs and health outcomes. Data extraction covered study type, health effects, exposure magnitude, and geographical distribution. A total of 65 studies were analyzed and categorized into experimental, epidemiological, and case-control designs.
Results: The findings indicate significant associations between ELF-EMF exposure and conditions such as childhood leukemia, DNA damage, and oxidative stress. Mental health outcomes, including anxiety and depression, were frequently studied but yielded mixed results. Occupational exposure studies revealed potential risks, particularly among power plant workers and utility staff, while residential exposures were linked to neurobehavioral changes and sleep disturbances. Nevertheless, inconsistencies across studies hinder conclusive risk assessment.
Conclusion: While certain health risks of ELF-EMFs are well supported, substantial gaps remain in understanding less-studied effects, such as cardiovascular and endocrine disruptions. Future research should prioritize long-term, real-world exposures and address methodological limitations. These efforts are critical for informing public health guidelines and mitigating the potential risks associated with ELF-EMFs.