The word Sahar is derived from “Arabic” word which means excessive awakening or sleeplessness. The primary cause of Sahar is the imbalance in the temperament of brain (due to hot and dry temperament) and secondarily due to some other medical condition. Poor health outcomes have been linked to sleep deprivation and poor sleep quality. Lack of sleep denotes a reduction in the regular sleep time due to environmental or psychological reasons. Insomnia is associated with an increased risk of comorbidities like hypertension, heart attack, type 2 diabetes, obesity, anxiety, depression and many more physiological functions. This article will discuss the impact of sleep on human health and its management through unani approach.