Why is morning sunlight important?
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Morning sunlight is crucial for setting your circadian rhythms, which are the internal biological processes that regulate the sleep-wake cycle, among other functions. According to , neurons that are sensitive to sunlight signal the brain that it is daytime, promoting alertness and triggering a series of biological cascades within every cell and organ of the body. This exposure results in a natural and healthy surge of cortisol, a hormone that supports wakefulness and immune function when elevated at the start of the day 1.
The light viewing early in the day is also the most powerful stimulus to ensure one's ability to feel awake during the day and to fall asleep at night. This is not a weak correlation; there are hundreds of peer-reviewed studies supporting this. Moreover, artificial lights cannot replace the effect of morning sunlight once the sun has risen. This asymmetry in our biology means that we require bright morning light to set various mechanisms in motion, but at night even a small amount of light can disrupt our circadian rhythms 2.
Additionally, getting morning sunlight, even if indirectly or on a cloudy day, can significantly boost mood and mental health, as well as aid in regulating the circadian clock 3. Samer Hattar and also discuss the importance of intensity and duration of sunlight exposure for regulating the circadian system and improving sleep patterns 4.
emphasizes the need to engage in this practice at least 80% of the days of one's life and offers practical advice on how to compensate for days when direct sunlight exposure isn't possible 5. Furthermore, morning sunlight exposure increases cortisol and dopamine levels, contributing to overall well-being, alertness, and better sleep at night 6. Lastly, behaviors such as getting morning sunlight are essential for overall hormone status and should be established before considering supplements for hormones 7.
The benefits of morning sunlight extend beyond circadian rhythm regulation to include improved metabolism, mood, focus, and alertness, and better nighttime sleep, with these effects likely being the result of improved sleep due to proper circadian timing rather than a direct effect of sunlight 8.