Background: Islamic instructions suggest waking up near dawn at night and spending time praying to Allah. This is the time of maximum melatonin secretion, that is a hormone mainly functioning in the circadian rhythm. Melatonin secretion declines with age and leads to different clinical consequences. This study aimed to investigate the melatonin levels among night vigil prayers, non-prayer late sleepers, and those with regular night sleep.Methods: A questionnaire including information about age, gender, education, and occupation was used to collect the demographic information of the participants. Melatonin was measured with two blood draws (at 23:00 to 24:00 and 9:00 to 10:00 a.m.). Results: There was a significant difference between both nocturnal and daily melatonin of the night vigil prayers with the other two groups. The average daily melatonin serum level had no significant difference in groups of regular night sleepers and the nonpraying late sleepers (p=0.306). Moreover, an adverse significant relationship was found between age and nocturnal melatonin (R=0.38, P<0.0001) and between age and daily melatonin (R=0.25, P=0.02).Conclusion: The night vigil prayers have a higher average of nocturnal and daily melatonin serum secretion compared to the nonpraying late sleepers and regular night sleepers. Therefore, waking up at night accompanied by approaching Allah, prayer, supplication, and good thinking is related to the release of more melatonin.

Sleep is one of the essential aspects of life that must be properly regulated, as it plays a significant role in maintaining physical health and mental well-being. Disturbance of sleep can hinder the normal course of human life. Imam Ali (pbuh) in the Nahj al-Balagha emphasizes sleep as one of the most important phenomena. The present study aims to analyze the semantic features of the word sleep (nawm) in Nahj al-Balagha using a descriptive-analytical method. Semantic features are the elements that characterize concepts in terms of presence or absence with positive (+) or negative (-) attributes. Changes in semantic features occur when a word is used in association with other words. A semantic feature is part of the meaning of a word that has nothing to do with sentences. The analysis of concepts through semantic features is called feature analysis. The results of the study indicate that, in *Nahj al-Balagha, terms such as "al-kari" (drowsiness), "al-sena" (sleepiness), "al-subat" (deep sleep), and "al-madmaḍa" (light sleep) fall within the semantic field of sleep, while words like "al-Tahajjud" (night prayer), "al-araqq" (insomnia), "al-ramiq" (vigilance), and "al-yaqza" (wakefulness) have an opposite semantic relationship with it. The semantic features of each of these terms are explained in this study. Additionally, the Nahj al-Balagha discusses two types of sleep, praiseworthy and blameworthy. Imam considers the sleep of the body and eyes praiseworthy, while the sleep of the mind (negligence) is deemed blameworthy.