Natural light on a field
Image by Hamed Saber.

It’s a widely-accepted opinion that higher levels of natural light lead to better, more efficient, more dedicated workers.

Theories about the benefits of natural light have affected everything from skyscrapers to conservatory designs.

But why does introducing natural light seem to work so well?

Theories vary, but here are some of the most compelling.

1. Natural Light Is Healthier For The Body

R.J. Wurtman M.D. wrote in 1985 that there are both direct and indirect medical and therapeutic benefits to certain spectra of light.*

This includes the obvious, such as preventing rickets, to the less obvious, such as having an effect on cavities in the teeth.

Another scientist, W.E. Hathaway PhD, followed up by specifying the areas of natural light we rely on for normal healthy functioning in 1992 – the areas he pinpointed as most important were in the ultraviolet and visible light range, in other words, the exact range visible light is most responsible for. †

Vitamin D production is undoubtedly important for all kinds of ailments, but it seems as though there’s another reason that natural light is so healthy for the body. Absenteeism and productivity seem to fall a lot more quickly than might be expected.

Given the strong effect that the mind can have on the body, it doesn’t seem too far out to suggest that…

2. Natural Light Is Healthier For The Mind

Seasonal Affective Disorder is a well-documented phenomenon, being a mood disorder that accompanies low lighting through the winter months. Not many would argue, then, that lighting doesn’t have an effect on your mood.

Affecting the ‘circadian’ or body clock also has an effect on many mentally degenerative illnesses such as Alzheimer’s, while one ‘meta-analysis’ (a study of a range of scientific studies) suggested that there  was “modest though promising anti-depressive efficacy” to increased natural light levels.

There are all kinds of complex psychological mechanisms that might explain why this would lead to healthier, more productive workers – but it seems simpler to attribute at least some of the improvement to feeling happier at your workplace, which means that you’re more likely to turn up.

3. Natural Light Seems To Be Healthier – Does It Matter Why?

My personal non-theory is that natural light has proven its worth in many a case study. Finding out how it works will be complicated and fiddly, but we can show quite clearly that it does work in some instances.

For example, Lockheed experimented with natural lighting in 1983, boosting contract productivity by 15%, and believed that the “higher productivity levels…helped them win a $1.5 billion defense contract.”

Verifone, a company operating out of Los Angeles, reported a 5% increase in productivity. Meanwhile, total product output increased by 25-28%.

The government study these figures were taken from cites a further 3 case studies of companies improving productivity after introducing natural daylight, along with some figures from schools.

So would all this focus on natural light make David Salisbury the healthiest man in the world?

There does seem to be convincing evidence supporting the idea that natural light improves health and worker productivity.

It also seems intuitively correct.

For now, though, we don’t really know how it works, or why. We know there are probably a lot of factors at play, and we are fairly sure that it does work, and that’s going to have to be enough!

*Wurtman, R.J., in the introduction to The Medical Effects of Light (Annals of the New York Academy of Sciences, Volume 453)

†Hathaway, W.E., “A Summary of Light-Related Studies.” A Study into the Effects of Light on Children of Elementary School Age