Reducing blue light exposure doesn’t mean eliminating screen time altogether. However, prolonged exposure to blue light—emitted by digital devices—can negatively impact sleep, eye health, and overall well-being. The easiest changes are things like reducing blue light exposure, getting good sleep, and cutting out chemical endocrine disruptors... Importantly, our semi-ecological protocol replicated the cortisol and alpha-amylase expression profiles during the baseline day which are consistent with the literature. Indeed, in a similar study, participants remained in the laboratory where no unexpected events could challenge them. First, participants slept in their own home, minimizing the impact of sleeping in an unfamiliar environment. No time effect or interaction between time and the sleep condition was significant for the calm or tense scales. For the memory task, we analyzed the recall performance throughout the day (i.e., were participants able to remember which items had been presented in the morning and which item were new). The correlation between the serum concentrations of the tested steroid hormones in all subjects is good. Cortisol originates from pregnenolone and provides one of the ways of transmitting the circadian message from the SCN to the peripheral tissues. Hormone levels were investigated using IBL ELISA enzyme immunoassays kits according to the manufacturer’s instructions (IBL America, Minneapolis, MN, USA). Chronotype was assessed by the "Morningness–Eveningness Questionnaire" (MEQ) —a questionnaire with 19 items and a total score ranging from 16 to 86 that is widely used in adults and workers 44,45,46. By understanding and addressing the impact of blue light exposure, you can take proactive steps to protect your hormonal health and maintain balanced levels. Poor sleep from blue light exposure reduces nitric oxide, dopamine, and testosterone—three pillars of strong sexual performance. Since blue light exposure affects sleep, taking steps to reduce it can lead to improved mental clarity, productivity, and overall well-being. In humans, the constant routine protocol experimentally removes external rhythms of light/dark, wake/sleep, and activity/rest by keeping subjects in constant conditions of dark, wakefulness and rest. Other hormone signals, such as cortisol, that entrain peripheral clocks to the CCP’s rhythm cannot serve this function because glucocorticoid receptors are not expressed in the SCN and adrenalectomy has no effect on the SCN clock (Oster et al., 2017). Skyglow is highly relevant because low-level light can still disrupt the circadian system (Usmani et al., 2024). Its pervasiveness is due in part from skyglow which is a diffuse luminance of the night sky when artificial light is scattered in the atmosphere and can be observed in geographical areas far removed from the original light source. Light pollution has ecological effects on flora and fauna, public health consequences for human wellbeing, and consumes energy and resources (Falchi et al., 2016). LEDs typically have a peak in the shorter wavelength (blue spectral) range, compared with the yellowish light of the moon. Artificial light at night (ALAN) was first officially recognized to be an environmental pollutant in 2020, yet awareness of its existence and hazards remains low (The Lancet Regional Health-Europe, 2023).