Health Risks of Indoor Lighting: Lessons from Dr. John Ott’s Full-Spectrum Light Research

Over 75 years ago, Dr. John Nash Ott, a pioneering photobiologist and time-lapse photography expert, began exploring how light influences the biology of plants, animals, and humans. His groundbreaking experiments revealed that the color and quality of light profoundly affected growth, behavior, hormonal balance, and even lifespan. Often referred to as the grandfather of full-spectrum lighting research, Dr. Ott discovered that artificial lighting, especially fluorescent and later LED light, failed to replicate the beneficial balance of wavelengths found in natural sunlight.

Today, red light therapy and full-spectrum lighting technologies are being revisited by modern science to restore the missing biological benefits of sunlight exposure. This article explores what the science says about why most indoor lighting is incomplete, and how red light therapy can help counteract the biological deficits caused by artificial light environments.

Dr. John Ott and the Discovery of Light’s Biological Effects

Dr. John Ott began his career photographing plant growth for Walt Disney Studios in the 1930s. He noticed that plants grown under glass windows or artificial light exhibited stunted growth and hormonal abnormalities. His curiosity led him to experiment with different wavelengths, discovering that light intensity and spectral composition directly influenced plant flowering, animal reproduction, and even behavior in humans.

Ott’s decades of research eventually led to the development of full-spectrum lighting, which mimics natural sunlight by including the full range of visible light (violet through red) plus near-infrared and ultraviolet wavelengths. He proposed that exposure to full-spectrum light could improve mood, vision, and overall physiological health, insights that were decades ahead of their time. [1]

Why Most Indoor Lighting Is Not Full-Spectrum

Modern indoor lighting — whether fluorescent, compact fluorescent (CFL), or LED, lacks critical portions of the light spectrum found in natural sunlight. Most of these sources emit a spiked, narrow wavelength range, typically strong in blue light but weak in red and infrared wavelengths.

This imbalance has several biological consequences:

• Circadian disruption: Blue-heavy light from screens and LEDs suppresses melatonin production, impairing sleep cycles.
• Visual strain: The narrow spectrum leads to glare and visual discomfort.
• Mitochondrial under-stimulation: The absence of red and near-infrared wavelengths means less cellular energy production and repair.

Studies show that prolonged exposure to such limited-spectrum lighting can contribute to fatigue, eye strain, and even hormonal imbalances. [2]

The Biological Importance of Full-Spectrum and Red Light

Natural sunlight includes wavelengths from ultraviolet (UV) through infrared (IR). These different portions of the spectrum affect the body in complementary ways.

• Blue light regulates circadian rhythms and alertness.
• Red and near-infrared light penetrate deep into tissues, supporting mitochondrial function and cellular repair.
• UV light triggers vitamin D synthesis and nitric oxide release.

When these wavelengths are out of balance, as in most indoor environments, biological processes can suffer. Red and infrared light, in particular, play a key role in energy metabolism and tissue recovery by stimulating mitochondrial cytochrome c oxidase. [3]

How Red Light Therapy Works

Red light therapy (RLT), also known as photobiomodulation, involves exposure to low-level wavelengths of red (600–700 nm) and near-infrared (700–900 nm) light. These wavelengths penetrate the skin and stimulate mitochondria, increasing ATP (adenosine triphosphate) production — the body’s cellular energy currency.

(Front. Chem., 09 June 2021).

As seen in the illustration, blue and green wavelengths do not reach much beyond the epidermis, but red and infrared reach the subcutaneous layer.

The therapy is now widely researched for its effects on:

• Wound healing and skin rejuvenation
• Muscle recovery and reduced inflammation
• Cognitive function and neuroprotection
• Mood enhancement and circadian rhythm regulation

Numerous clinical studies confirm that RLT can reduce inflammation, accelerate healing, and improve energy metabolism at the cellular level. [4]

Red Light and Circadian Health

Light exposure determines the rhythm of human biology. The absence of natural light during the day and excessive artificial light at night confuse the body’s circadian clock. Red and infrared wavelengths have a calming, restorative effect on the nervous system, especially in the evening.

Studies show that exposure to red light before sleep can increase melatonin secretion and improve sleep quality without the disruptive effects of blue light. Incorporating full-spectrum or red-light sources during the evening can help counteract circadian misalignment caused by screen exposure and poor indoor lighting. [5]

Red Light Therapy for Skin and Anti-Aging

Red light therapy stimulates collagen production and accelerates tissue repair, making it an increasingly popular tool for dermatology and cosmetic applications. Controlled trials show significant improvements in skin tone, elasticity, and wrinkle reduction after consistent RLT exposure.

Unlike ultraviolet light, which can damage skin cells, red and near-infrared light promote healthy regeneration without harmful radiation. This is one of the best-documented uses of RLT, supporting its safety and long-term effectiveness. [6]

Cognitive and Mood Benefits

Light doesn’t just affect the skin - it directly impacts the brain. Red and near-infrared light penetrate the skull and enhance mitochondrial energy production in neurons. Research indicates that RLT can improve mood, reduce symptoms of depression, and enhance cognitive performance, especially in people with seasonal affective disorder (SAD) or those deprived of natural light exposure.

This is consistent with Dr. Ott’s early observation that schoolchildren in classrooms without natural light had higher rates of hyperactivity, fatigue, and attention problems compared to those in sunlit rooms. [7]

Mitochondrial Health and Longevity

Mitochondria are the powerhouses of our cells, and their function is deeply tied to light exposure. Red and near-infrared light are particularly effective at stimulating mitochondrial enzymes, leading to increased ATP production and improved cell function.

Long-term, this may have implications for aging and chronic disease prevention. Studies suggest that RLT can help reduce oxidative stress, improve metabolism, and promote longevity by supporting mitochondrial efficiency. [8]

Combating the Health Costs of Artificial Light Exposure

Modern humans spend over 90% of their time indoors, under lighting that fails to reproduce the spectral richness of sunlight. This mismatch between our biology and environment contributes to what researchers call “malillumination” - the light equivalent of malnutrition.

Using full-spectrum light bulbs, getting regular outdoor sun exposure, and incorporating red light therapy are ways to mitigate these effects. Regular use of RLT can restore part of the missing red and near-infrared exposure critical for optimal cellular function. [9]

The Future of Lighting and Health

As our understanding of photobiology expands, researchers are beginning to rethink indoor lighting design. Integrating human-centric lighting systems - which mimic the natural spectral and temporal dynamics of sunlight - may revolutionize health outcomes in workplaces, schools, and hospitals.

In a sense, this represents the modern realization of Dr. John Ott’s vision: light as a nutrient, essential to health and vitality. By blending full-spectrum illumination with targeted red light therapy, we may be able to bring the healing power of sunlight back indoors. [10]

Conclusion

Dr. John Ott’s pioneering work illuminated an enduring truth: light is not just something we see - it’s something our biology depends on. Modern science has confirmed many of Ott’s early observations, showing that full-spectrum and red light exposure profoundly influences our sleep, mood, energy, and overall health. As we continue to spend more time indoors, reintroducing the full spectrum of light, especially red and near-infrared, may be one of the most powerful steps toward restoring our well-being.

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 References 

1. Ott, J. N. (1973). Health and Light: The Effects of Natural and Artificial Light on Man and Other Living Things. New York: Devin-Adair.
2. Cajochen, C., et al. (2011). Evening exposure to a light-emitting diodes (LED)-backlit computer screen affects circadian physiology and cognitive performance. Journal of Applied Physiology, 110(5), 1432–1438. https://doi.org/10.1152/japplphysiol.00165.2011
3. Hamblin, M. R. (2017). Mechanisms and mitochondrial redox signaling in photobiomodulation. Photochemistry and Photobiology, 93(6), 912–929. https://doi.org/10.1111/php.12724
4. Chung, H., et al. (2012). The nuts and bolts of low-level laser (light) therapy. Annals of Biomedical Engineering, 40(2), 516–533. https://doi.org/10.1007/s10439-011-0454-7
5. Zhao, J., et al. (2012). Effects of red light on sleep quality in Chinese female basketball players. Journal of Athletic Training, 47(6), 673–678. https://doi.org/10.4085/1062-6050-47.6.08
6. Avci, P., Gupta, A., & Hamblin, M. R. (2013). Low-level laser (light) therapy for skin rejuvenation. Seminars in Cutaneous Medicine and Surgery, 32(1), 41–52. https://doi.org/10.12788/j.sder.0005
7. LeGates, T. A., Fernandez, D. C., & Hattar, S. (2014). Light as a central modulator of circadian rhythms, sleep and affect. Nature Reviews Neuroscience, 15(7), 443–454. https://doi.org/10.1038/nrn3743
8. Hamblin, M. R. (2016). Shining light on the head: Photobiomodulation for brain disorders. BBA Clinical, 6, 113–124. https://doi.org/10.1016/j.bbacli.2016.09.002
9. Figueiro, M. G., & Rea, M. S. (2010). Lack of short-wavelength light during the school day delays dim light melatonin onset (DLMO) in middle school students. Neuroendocrinology Letters, 31(1), 92–96.
10. Brown, T. M., & Brainard, G. C. (2020). Cumulative photobiological effects of light: Implications for human health. Annual Review of Neuroscience, 43, 89–110.