Why can't you get sun exposure through glass?
May 30, 2025
Source: Cainiu Health
Dr. Bai Hongmei
Introduction
Under normal circumstances, the reasons why sunbathing through glass is not recommended include limited penetration of ultraviolet rays, reduced warming effect of infrared radiation, decreased transmission of beneficial light, changes in light wavelength and energy distribution, and a potential increased risk of skin problems. To fully enjoy the benefits of sun exposure, such as vitamin D synthesis, improved mood, and regulation of circadian rhythm, it is advised to be outdoors and directly exposed to sunlight whenever possible.
Generally speaking, the reasons why sunbathing through glass is not recommended include limited ultraviolet penetration, reduced infrared warmth effect, decreased transmission of beneficial light, altered light wavelength and energy distribution, and potentially increased risk of skin problems. Details are as follows:
1. Limited Ultraviolet Penetration
Ordinary glass effectively blocks most of the ultraviolet B (UVB) rays, which are the wavelengths necessary for vitamin D synthesis. When sunbathing through glass, the body cannot absorb sufficient UVB radiation, thus affecting vitamin D synthesis, potentially leading to poor calcium absorption and impacting bone health.
2. Reduced Infrared Warmth Effect
Infrared rays, part of sunlight, provide warmth and promote blood circulation and metabolism. However, glass reduces the penetration of infrared radiation. When sunbathing through glass, the warmth perceived by the body decreases, which may affect comfort and blood circulation.
3. Decreased Transmission of Beneficial Light
Sunlight contains various types of beneficial light, such as blue light in the visible spectrum, which helps regulate circadian rhythms and improve mood. However, glass weakens the penetration of these beneficial rays. When sunbathing through glass, the body cannot fully receive these beneficial rays, potentially affecting mood and circadian rhythm regulation.
4. Altered Light Wavelength and Energy Distribution
Glass can change the wavelength and energy distribution of light, causing differences in biological effects between sunlight passing through glass and direct sunlight. This alteration may affect how light interacts with human cells and tissues, reducing the health benefits of sun exposure.
5. Potentially Increased Risk of Skin Problems
Although sunbathing through glass itself does not directly increase the risk of skin problems, due to limited UV penetration, individuals may extend their sun exposure time trying to obtain sufficient UV radiation. This may inadvertently increase the skin's exposure time to UV radiation, especially during periods of high UV intensity.
To fully enjoy the benefits of sun exposure, such as vitamin D synthesis, improved mood, and circadian rhythm regulation, it is recommended to get direct sunlight outdoors as much as possible. When sunbathing, appropriate protective measures should also be taken, such as applying sunscreen and wearing sun-protective clothing, to avoid skin damage from excessive UV exposure.
