Cycle-dependent oscillations in sex hormones have an effect on sleep and cognition [59]. In addition, Baker
Cycle-dependent oscillations in sex hormones influence sleep and cognition [59]. Also, Baker and Drivers [60] reported hormonal cycle-dependent modifications in sleep architecture in naturally cycling women. Though males are less subject to month-to-month hormonal fluctuations, melatonin [61] and cortisol [62] secretion are also affected by seasonal modifications in men. Besides these troubles of our study protocol and our sample, research examining light influences differ significantly relating to the applied show size and sort (e.g., LED or LCD screens and computer systems, e-book readers or tablets/smartphones), brightness and size. Moreover, Chellappa [3] concludes that circadian photosensitivity is topic to interindividual differences, i.e., the response to artificial light in the evening, like adjustments of circadian parameters, varies largely across people. An instance for anClocks Sleep 2021,Seclidemstat supplier person trait accountable for the higher variance in light-susceptibility across men and women might be eye pigmentation, as 1 study reported stronger melatonin suppression in subjects with lighter eye colors (i.e., blue, green or light-brown iris in comparison to dark brown iris) [63]. As a result, we can not rule out that we included a lot more high- than low-responders or the other way around. Apart from basic interindividual variations in sensitivity to light, it can be additionally affected by age [28]. Younger adults showed much stronger lightinduced adjustments in circadian (i.e., endogenous melatonin secretion) and sleep parameters (i.e., frontal SWA), subjective sleepiness and focus in contrast to older adults. This may possibly not happen to be a problem concerning the present results, as our study sample consists of a really homogeneous age group, but rather a problem concerning comparability between studies investigating light exposure with subjects of diverse age groups. Future research must hence address this concern regarding basic interindividual and age-related variations in light-responsiveness to obtain extra insight in to the interaction among the day-to-day present artificial light consumption and our inner clock. four. Supplies and Approaches 4.1. Participants 33 healthy male subjects (imply age: 21.70, standard deviation: 1.91, range: 185 years) had been recruited and examined at the University of Salzburg among October 2019 and December 2020. The present outcomes extend our already published preliminary information of a subset of 14 participants [64]. All subjects had been cost-free of medication, non-smokers and reported no history of drug abuse, night-shift operating, neurological or psychiatric illness. Additional, they were right-handed, showed no above typical caffeine consumption (i.e., 3 cups of coffee, or 1 energy drink per day) and were not extreme chronotypes (defined as subjects with raw sum-scores under 31 or above 69) according to the German version from the morningness-eveningness questionnaire [65]. For the whole study period sleep habits had been monitored with wrist actigraphy (Cambridge Neurotechnology Actiwatch, MCC950 Protocol CamNTech Ltd., Cambridge, England) and sleep diaries (“morning/evening protocol”; adapted version of Saletu and colleagues [66]) to assure a typical sleep-wake cycle. Participants were remunerated with either 100 Euros and 16 h not surprisingly credit for participation in scientific studies or with 50 Euros and 24 h needless to say credit. All participants provided written informed consent. The study was approved by the neighborhood ethics committee and performed in accordance together with the most up-to-date v.