My last blog was on ultraviolet light, now one on infrared. Do we detect an “unseen” pattern here?
Here’s an interesting twist that few people saw coming. The Journal of Environmental Psychology recently published a report, “Effects of near-infrared radiation in ambient lighting on cognitive performance, emotion and heat rate variability.” While this is an early study and the paper itself states that additional research is needed, this initial review indicates that light minus the near infrared radiation (NIR) found in the sun may have some implications on human health.
Upon the introduction of LED, the elimination of IR light was hailed as a benefit. IR can damage tissues and cells on the body and is typically manifest as a sun burn or eye damage, such as cataracts. This study now indicates that the total elimination could cause some additional concerns, especially as humans spend so much more time indoors under artificial light; more so than our predecessors in an agrarian economy.
In a double-blind study, 151 students were monitored, half in light that contained a normal level of NIR (daylight,) compared with the other half subjected to near zero NIR, typical of standard LED lighting. The absence of NIR was found to influence the human’s physiological and psychological levels.
- Cognitive performances improved in the participants who received light with normal levels of NIR, resulting in better attention, better perception, improved short term memory, increased working memory and better executive function.
- Mood also improved in the participants who were tested under light with NIR. They showed increased levels of pleasure, more alertness and higher levels of environmental satisfaction.
- Subjects exposed to the typical levels of NIR showed beneficial effects on resting high-frequency heart rate variability (HF-HRV) and the HF-HRV response to cognitive demand.
Our old incandescent and fluorescent delivered plenty of light in the infrared range. With LED in the midst of a near total domination of both commercial and industrial settings, humans will be experiencing substantially lower levels of NIR than generations prior. This possible impact on humans must be balanced against the benefits as well as the energy savings earned by more efficient LED. Again, remember, this is an EARLY study. The scientific community will be digging into this issue over the next decade. Stay tuned.
Interested in reading the entire study?
https://www.sciencedirect.com/science/article/pii/S0272494424002573
Lighting by Jeffrey 