Why is looking at sunlight through a window less effective than if it were open?
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Viewing sunlight through a window is significantly less effective for stimulating the wake-up signal in your brain and body compared to direct sunlight exposure. This reduced effectiveness is mainly because windows filter out a lot of the blue light wavelengths that are essential for stimulating melanopsin-containing cells in the eye, which are crucial for activating our circadian system.
explains that sunlight coming through a window can be 50 times less effective at activating the circadian system than direct sunlight due to this filtering effect. These specific wavelengths of blue light are key in waking up the brain and body through the melanopsin hypothalamus system. Therefore, he recommends getting sunlight exposure outside or through an open window for optimal benefits 1 2 3 4 5 6 7 8.
