Effects of near-infrared radiation in ambient lighting on cognitive performance, emotion, and heart rate variability
Bibliographic record
Abstract
Although sunlight contains approximately equal amounts of near-infrared radiation (NIR) and visible light, NIR is absent from most present-day electric lighting systems and is filtered by energy-efficient windows. However, NIR is biologically active and is commonly applied in targeted photobiomodulation treatments for a range of cognitive, emotional, and physical conditions. Given the removal of NIR from indoor illumination, it is critical to understand how ambient NIR may influence psychological and physical health, and whether reduced exposure to NIR in indoor environments could be cause for concern. In a preregistered within-subjects double-blind experiment, acute effects of NIR and far-red wavelengths in ambient illumination on cognition, emotional state and cardiovascular health were examined in a sample of 151 university students (117 females, 34 males). During a 2-hour laboratory session, participants were monitored at rest and while engaged in cognitively demanding tasks across two counterbalanced lighting conditions. Both included 3500 K white light generated by a light-emitting diode (LED) system, while one additionally included LEDs with peak wavelengths in the NIR (875 nm, 960 nm) and far-red (735 nm) spectrum. The addition of NIR and far-red to the ambient lighting showed beneficial effects on resting high-frequency heart rate variability (HF-HRV), HF-HRV responses to cognitive demand, and feelings of pleasure, but reduced performance on a visual search task. These findings reveal that the absence of NIR from architectural lighting influences humans at a psychological and physiological level, with implications for health and well-being that need to be balanced with energy-saving considerations. • Ambient NIR exposure positively influences parasympathetic activity via HRV • NIR in ambient lighting may enhance pleasure, suggesting protective effects on mood • NIR wavelengths influence resting HRV and HRV responses to cognitive demand • Exclusion of NIR from lighting may have health implications needing further study • Balancing energy efficiency with NIR inclusion could optimize health and productivity
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".