The Science

Light Impacts Health and Well-Being

Over the past two decades, researchers have begun to understand just how important light exposure is for human health. By activating special cells in our retinas–the ipRGCs (intrinsically photosensitive retinal ganglion cells)–light helps set our circadian rhythms. Disruptions to these rhythms are linked to poor sleep, impacting alertness and performance, as well as increased risk for diseases such as diabetes and cancer. Active research is ongoing in this area, and Blue Iris products are used by the NIH and researchers at Mt. Sinai, among others.

The Lighting Research Center (LRC) at Rensselaer Polytechnic Institute is a major subcontractor and key collaborator in our current NIH-funded grant. In this TEDMed talk, LRC Director Dr. Mariana Figueiro reveals surprising facts about the effects of light — its presence, its absence, and its patterns — on human health.

About 24-Hour Circadian Rhythms

The human hypothalamus gland is a “biological clock” in our brains with a cycle that is approximately 24 hours long, called our circadian rhythm (“circadian” is Latin for “around the day”). This cycle regulates our internal biological activities, including our sleep patterns; wakefulness; behaviors; and our physiological, mental, and emotional processes.

When our circadian rhythms are aligned, we sleep better and feel better. But our circadian rhythms can become misaligned, damaging our health and well-being. Jet lag is a well-known example of such circadian misalignment. Research has shown how light intensity and light spectrum can support — or disrupt — our circadian rhythms.

Measuring in the Lab vs. in the Real World

Most light and health studies have been conducted in highly controlled laboratory environments where researchers can carefully manage and monitor lighting conditions, along with many other variables, to generate data that can be used to pinpoint causal relationships between specific lighting conditions and specific health outcomes.

These studies have been restricted to laboratories and other experimental settings because spectrometers — the tools that measure light accurately and in full spectral detail — are large and expensive. Real-world lighting conditions are complex and changing, especially for a person moving through space. Without small lab-grade spectrometers, we can’t fully understand the lighting exposure people experience in real-world settings, or how variations in lighting impact human health. With the Speck, these measurements, and the consequent knowledge, are now possible.

The Challenge of Measuring Light

Measuring light is quite different from measuring a simple variable like temperature. For the latter, you can place a sensor and get “the answer” of how hot or cold it is there. But measuring light is much more complex; instead of one answer, there are many.

Light varies by:

  • Intensity
  • Spectrum
  • Direction/orientation
  • Source: small and intense (like ceiling lights) or large and diffuse (like reflections off walls).
All these differences matter to human physiology.

A New Tool for Lighting Field Measurements

Blue Iris Labs currently has received a multi-year grant from NIH (the National Institutes of Health) to develop lighting systems that positively impact the health of Alzheimer’s patients, and those with dementia and sleep-related disorders.

The NIH project required accurate, yet easy-to-deploy measurement systems to determine how light levels and spectrum are experienced by Alzheimer’s patients. We found that no such measurement devices currently exist, so, as part of this project, we have successfully built systems from the ground up.

Our approach encompasses our decades of expertise in lighting science and in capturing field measurements of lighting systems. Blue Iris Labs is also built on a team with deep understanding of the tools and techniques available today in wireless communications, embedded systems, cloud computing and big data analytics.

These measurement systems are now being made available to researchers, lighting professionals, building scientists, and others to further our understanding of the impact of lighting on living things, and beyond.

Validated by NIH and in trial at the Oregon Health & Science University School of Medicine, Blue Iris Labs is the first and only company to provide a system to be able to precisely measure circadian light levels and spectrum with easy-to-install in-room spectral sensors across a variety of real-world environments.

Take a Deeper Dive into the Science of Circadian Lighting

For a more detailed discussion of the science of circadian lighting, click here.

This link provides more information on:

  • An overview of how light impacts our sleep and our circadian rhythms
  • How these impacts people with Alzheimer’s Disease and related dementia
  • How circadian light and circadian stimulus can be measured
  • A detailed list of technical references on these and related topics