29 April 2020

Why a ‘Corona-Blog’?

The Daylight Academy seeks to be both a laboratory of ideas and a mouthpiece for topics related to daylight research. One of its central objectives is to improve awareness and understanding of the health benefits natural light can provide. Daylight offers many advantages ranging from enabling excellent visual performance and good eyesight to permitting entrainment of the circadian system and production of vitamin D. Spending enough time outside in daylight contributes to many aspects of our health and well-being. Besides, it is free and accessible to all (albeit in different amounts depending on geography, season, and weather). Spreading knowledge about daylight can positively impact public health and is always important, but is perhaps more crucial now that we are facing a viral threat which forces us to spend even more time indoors. Our ‘Corona-Blog’ is not intended to contradict official recommendations, call into question the logical containment measures adopted in many countries, or provide miracle solutions. It aims to open a space for reflection and exchange where daylight experts can share their vision on the varied roles daylight could play to help us remain healthy and functional during this challenging period.

Circadian rhythm

Natural light and darkness give our body clocks essential time cues to stay in sync with the outside world. Robust and synchronised circadian rhythms are at the core of good health. In these times of confinement, it is therefore important to get enough daylight in order to avoid any circadian disruption. “Adverse health effects, in which the lack of sufficient daylight has been directly (daily light and dark exposure) or indirectly (via circadian misalignment) involved, range from sleep problems and impaired daytime functioning to increased prevalence of chronic diseases such as depression, obesity, diabetes, cardiovascular diseases and cancer.”

Experts recommend enjoying daylight at least 30 minutes per day. If going outside is not possible, enough time should be spent close to a window. Adequate exposure of the eyes to natural light helps regulate the sleep-wake cycle and increase sleep quality, which can be particularly beneficial in times when stress and uncertainty might make falling asleep more difficult. Furthermore, good and regular sleep is likely to contribute to maintaining a well-functioning immune system: “Studies have shown that chronically sleep-deprived animals and humans have weaker immune systems, making it easier for even mild infections and viruses to gain entry to the body and cause more damage or even death”. Not only bad sleep can disturb our body’s defences, the immune system seems to rely on a healthy and consistent circadian rhythm to produce the appropriate response.

Vitamin D and the immune system

One further reason to seek daylight during the current corona crisis could be found in the need for vitamin D. The easiest and most natural way to get the valuable vitamin is to expose our skin to sunlight. Whether vitamin D can help fight the new coronavirus is yet to be demonstrated. Nonetheless, several studies suggest that healthy levels of vitamin D are generally associated with a performant immune system and reduced risks of infection.

Sunlight as a disinfectant

The sun has a well-known germicidal effect. Through its ultraviolet rays, it can neutralise germs, bacteria, and viruses. “Sunlight or, more specifically, solar UV radiation (UV) acts as the principal natural virucide in the environment. UV radiation kills viruses by chemically modifying their genetic material, DNA and RNA.” This natural power is for example used to disinfect water in developing countries. Regarding the coronavirus, scientists have “found that ultraviolet light was most strongly associated with lower COVID-19 growth rates”. Consequently, they also assume that summertime might slow down the virus. However, these findings are still preliminary and the authors remain cautious: social distancing and other protective measures are likely to remain necessary.

These are just some of the topics to be further explored and discussed in this blog. There are of course other areas where the close links between natural light and health could be of special significance now. Can daylight, for example, boost mood and improve mental health? Is this health crisis challenging certain architectural principles and calling for a healthier built environment? The questions discussed in this blog are not only relevant in such an exceptional context. They are likely to remain highly relevant in the future, not only because the virus might stay with us for some time to come, and other health threats could arise, but also because the potential of daylight to improve our health and well-being deserves to be more widely known under any circumstances.