Introduction
Artificial lighting has transformed modern life. Blue-enriched LED lighting and prolonged evening screen use now extend light exposure well beyond sunset.
Strong evidence shows that blue light at night disrupts circadian rhythm and suppresses melatonin. Emerging research from Nature Scientific Reports (2025, 2026) suggests that light spectrum composition may also influence mitochondrial respiration and systemic energy metabolism.
This article reviews what is well established and what remains under investigation.
Blue Light and Circadian Rhythm
The circadian rhythm regulates sleep-wake cycles, hormone timing, metabolism, and immune function.
Intrinsically photosensitive retinal ganglion cells (ipRGCs) contain melanopsin, most sensitive to blue wavelengths (460–480 nm). Evening blue light exposure suppresses melatonin and delays circadian phase.
Evidence: Cajochen et al., J Clin Endocrinol Metab (2005); NIH; Harvard Medical School.
Modern LED Spectrum and Mitochondrial Respiration (Scientific Reports, 2026) A 2026 Scientific Reports study demonstrated that standard LED lighting provides a narrow spectrum (350–650 nm) compared to natural sunlight (300–2500 nm).
Shorter blue wavelengths (420–450 nm) were associated with reduced mitochondrial respiration in experimental conditions, while longer wavelengths (670–900 nm) enhanced mitochondrial respiration.
Supplementation with broader spectrum light improved visual performance for weeks after exposure. Long-term disease implications remain under investigation.
Systemic Effects of Longer Wavelengths (Scientific Reports, 2025)
A 2025 Scientific Reports study found that longer wavelengths (830–860 nm) from sunlight can penetrate human tissue and may produce systemic biological effects.
Short exposures were associated with improved visual function 24 hours later. Authors proposed enhanced mitochondrial ATP production as a mechanism. Further long-term human studies are required.
Clinical Interpretation
Strong evidence supports managing evening blue light to protect circadian rhythm and sleep quality.
Emerging evidence suggests full-spectrum light exposure may influence mitochondrial function, but direct mitochondrial damage from consumer-level LED or screen exposure has not been established.
Most evidence-supported pathway:
Evening blue light → circadian disruption → sleep impairment → metabolic stress →
potential downstream mitochondrial effects.
Clinical Recommendations – One Vision Eyecare
- Prioritize morning outdoor light exposure.
- Dim indoor lighting after sunset.
- Reduce evening screen brightness and no screen exposure 2 hours before bed.
- Maintain consistent sleep timing.
For patients using devices in the evening, yellow-tinted Hoya blue light blocking lenses can filter melanopsin-sensitive wavelengths and may support healthier melatonin signaling when combined with good sleep hygiene.
References
- Cajochen C et al. J Clin Endocrinol Metab. 2005.
- Scientific Reports (Nature Portfolio). LED lighting suppressing mitochondrial respiration. 2026.
- Scientific Reports (Nature Portfolio). Longer wavelengths systemic effects. 2025.
- National Institutes of Health – Circadian Biology.
- Harvard Medical School – Blue light research.
