Good Light might save $410 billion a year

A blog by Bruno Smets.

Lack of sleep has a substantial impact on people’s health and well-being, as well as on their cognitive performance and work-place productivity. Based on a preliminary literature review, we conclude that the improvement of workplace productivity by exposure to good light might amount up to 410 billion $ per year for five major OECD countries. No reliable data are yet available to estimate the long-term economic impact of good light on health and well-being.

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We as the Good Light Group advocate the beneficial effect of the right light at the right time for people’s health and well-being. In this blog a first attempt to quantify the socio-economic impact of good light is made.

In 2016 the RAND institute published an extensive study on the impact of sleep deprivation on the economy. This study is seen as a key reference in most sleep publications. For adult people insufficient sleep duration impairs health and well-being, resulting in an increased mortality risk. People sleeping less than six hours a night have a 13% higher mortality risk than people sleeping seven to nine hours, as recommended by the health authorities. People sleeping between six and seven hours still have a 7% higher mortality risk than the reference group. The authors however were not able to translate this substantial health effect into economic data.

Lack of sleep also decreases the cognitive performance and work place productivity of adults. For five major OECD countries, i.e.: the US, Canada, the UK, Germany and Japan the RAND team managed to quantify the effect of a lack of sleep on workplace productivity, caused by absenteeism as well as presenteeism. The direct economic cost has been estimated to amount to 680 billion dollars per year. Half of this cost has been attributed to people sleeping less than six hours a night, the other half to people sleeping between six and seven hours a night. Sleeping less than six hours decreases productivity by 2.4 %, while sleeping between six to seven hours still has a negative impact on the work place productivity, amounting to 1.4%. Sleep deprivation will largely vary from one country to another, but is substantial in all cases.

In the RAND recommendations to change this for the better, light has nowhere been mentioned. Nevertheless, at that moment in time some smaller studies already indicated that light has a substantial positive impact on sleep duration. Boubekri et al. in 2014 showed that people working in windowless offices on average sleep around one hour less per night than people working in an office with daylight exposure. Combining these results with the ones in the RAND report, would indicate that the economic impact of sleep deprivation on work place productivity might be more than halved, by exposing employees to sufficient light during daytime. The cohort sleeping normally between six and seven hours would get the recommended amount of sleep, i.e.: between seven and nine hours, bringing their productivity to the level of the reference group and almost completely eliminating the economic loss related to it. A substantial improvement of the work place productivity might be anticipated for the cohort sleeping normally less than six hours, because most of them will sleep longer as well. Based on the available data it is however not feasible to quantify this improvement exactly. In the following table it is assumed that half of the cohort sleeping less than six hours will get 6 to 7 hours of sleep after exposure to Good Light and its productivity consequently will improve. The other half on the contrary would not show sufficient improvement in sleep duration to affect their productivity. Based on the improvement of productivity shown, exposing people to the right light at the right time, might save society up to 410 billion $ in direct costs per annum for the five OECD countries studied.

Over the last years our insights in the role of light on health and well-being has drastically increased, culminating in the recommendations for the exposure to light during daytime, in the evening and at night by a group of specialists in the field. On the basis of these recent insights, academia must be able to design more extensive studies, enabling us to quantify the effect of good light on workplace productivity more accurately. The socio-economic impact of good light is not solely confined to the direct cost of work place productivity, but also includes its long-term effect on health and well-being. Till now, no reliable data could be surfaced to quantify the additional benefits of good light on long-term health and well-being.