Sleep is closely related to health behaviors and is also a crucial lifestyle in itself. In this regard, sleep health should be a part of assessing and managing chronic fatigue in the clinical field. First, it is vital to get in the early morning sun and improve sleep hygiene for proper melatonin secretion. Second, relaxation, meditation, or nutritional supplementation can be helpful to prevent sympathetic nervousness in the evening. Third, it is important to re-recognize and regain the health blessings of rapid eye movement sleep in the early morning. Lastly, meals tailored according to the biological clock (chrono-nutrition) can facilitate gut microbiota s healthy flourishing and the 24-hour circadian rhythm. When assessing and treating patients with chronic fatigue, functional medicine approaches are another essential step for improving the quality of life and advanced health care, based on a broad understanding of sleep science.