• Why does morning sunlight improve sleep?

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    Morning sunlight plays a crucial role in improving sleep quality and overall circadian rhythm. When you expose your eyes to sunlight in the morning, it serves as a powerful stimulus for your body's physiological systems, particularly setting your internal clock, which has a profound impact on sleep and wakefulness patterns.

    Here are some of the key benefits of morning sunlight as outlined by :

    1. Regulates Cortisol Levels: Exposure to bright sunlight in the morning increases the amplitude of the morning cortisol spike by as much as 50%. This is beneficial because cortisol should be highest in the morning to enhance mood, focus, and alertness during the day, while lower levels in the evening facilitate better sleep 1.

    2. Sets Circadian Rhythms: Sunlight in the morning helps set the circadian clock by signaling the brain what time of day it is, which helps regulate the sleep-wake cycle. This is achieved through non-image forming cells in the eyes that are sensitive to bright light for setting biological rhythms 1 2.

    3. Suppresses Melatonin: Morning light helps suppress melatonin, the hormone that promotes sleepiness, thus fully awakening the system and maintaining alertness throughout the day 3.

    4. Improves Metabolic Health: Regular exposure to morning sunlight not only benefits sleep but also has positive effects on metabolism, likely due to improved sleep quality rather than a direct effect of light itself 4.

    5. Enhances Overall Well-being: It improves mental and physical health by increasing alertness, reducing anxiety, and even decreasing symptoms of depression, making it a simple, no-cost intervention for better sleep health 5.

    By prioritizing time outdoors in the morning, ideally between sunrise and a few hours after, these benefits can be maximized, thereby positively impacting sleep and overall health.

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