Dr. Hattar explains how light exposure, particularly in the morning, is essential for synchronizing the body's circadian clock with the solar day. He highlights the role of specialized photoreceptors in the eyes that regulate this internal timing, even in individuals with limited vision. The discussion covers practical tools like morning sunlight exposure, dimming lights in the evening, and limiting screen time to support healthy sleep patterns. The impact of light on mood, stress, appetite, and learning is explored through the tripartite model, which integrates circadian, homeostatic, and environmental factors. Strategies for managing jet lag, seasonal depression, and Daylight Savings Time are also addressed, emphasizing the importance of aligning light exposure, meal times, and daily routines with natural biological rhythms for optimal mental and physical health.