Sleep is rigorously controlled by circadian rhythms, and any discrepancy between these rhythms and the external environment might result in circadian rhythm sleep disorders. Circadian rhythm sleep disturbances (CRSDs) are linked to detrimental health outcomes, including cancer and psychiatric illnesses. This systematic literature review explores the significance of disturbances of sleep and circadian rhythm. A systematic literature survey was conducted using PubMed, Scopus, Web of Science, Embase, and Cochrane Library databases. We used the following search terms: "Circadian clock," "sleep," " Circadian rhythm," sleep disorders," "drugs to cure sleep and circadian rhythm," and "CRSD." for articles published between 2018 and 2023. This comprehensive review presents evidence from human research to assess the concept that sleep and circadian rhythms have direct effects on physiological processes in the human body and are significant underlying factors contributing to major health concerns. The first part of this review focussed on sleep and circadian rhythm, circadian clock and effects of altered metabolism.” The second part discussed recent evidence that the circadian clock system plays a fundamental rolein health risk, adverse effects on health, and their connection with disturbances of sleep and circadian rhythm. These research lines are still in their early stages, but they have nonetheless established a conceptual framework that could be highly significant for comprehending metabolic health and illness