In this latest video from MedCram, Dr. Seheult discusses a study on how sunlight and near infrared radiation can penetrate the body and its effects.
A groundbreaking study published in Scientific Reports on July 8, 2025, titled “Longer Wavelengths in Sunlight Pass Through the Human Body and Have a Systemic Impact Which Improves Vision” by Glen Jeffery, Robert Fosbury, Edward Barrett, Chris Hogg, Marissa Rodriguez Carmona, and Michael Barry Powner, offers compelling evidence that longer wavelengths of sunlight—particularly in the near-infrared (NIR) range—can penetrate the human body and improve mitochondrial function systemically. This research confirms and extends prior findings discussed on MedCram and in earlier literature showing that light, especially in the red to infrared spectrum, interacts with mitochondria to reduce oxidative stress and increase ATP production. Since mitochondrial dysfunction is a key contributor to most chronic diseases and aging, this opens promising therapeutic avenues.
Previous studies support this direction. For instance, a 2019 paper by Scott Zimmerman and Russell Reiter explained how near-infrared light can be absorbed by the mitochondrial electron transport chain, particularly in Complex IV (cytochrome c oxidase), leading to improved energy production and reduced oxidative damage. A randomized controlled trial published in 2023 showed that COVID-19 patients treated with 940nm infrared light recovered more quickly, being discharged four days earlier than controls. Another study from Glen Jeffery’s lab showed that exposing individuals to 670nm red light led to a 27% reduction in glucose spikes following meals, suggesting that mitochondrial enhancement via light exposure could yield systemic metabolic benefits.
The newly published 2025 study took this further by showing that infrared light at 850nm passes through the thorax—even when clothed—and has whole-body effects. Remarkably, vision improved 24 hours after exposure, even in subjects whose eyes were fully shielded from the light. This demonstrated a systemic benefit rather than a local one and aligned with the “abscopal effect”—a phenomenon previously observed in animal models where targeted light therapy in one body area yields benefits in another. These findings suggest light absorbed by tissues can result in the release of signals or molecules that affect other parts of the body.
Interestingly, despite only about 0.004% of the 850nm light passing through the body, it was sufficient to trigger measurable biological changes. The light interacts primarily with mitochondrial proteins, particularly those in Complex IV of the electron transport chain. The study focused on color vision as a readout for mitochondrial performance, given that the retina—specifically the cone cells—has one of the highest mitochondrial densities in the human body. Researchers assessed color vision using a Cambridge Color Test, which determines thresholds for detecting variations in red (protan), green (deutan), and blue (tritan) shades.
Participants were divided into three groups: one receiving no light exposure (control), another receiving 850nm light to the entire body and head, and a third group exposed only to body-targeted light while the head was shielded with reflective aluminum. The results revealed that both groups exposed to infrared light experienced improvements in color perception, particularly in the protan (red) and tritan (blue) channels. Notably, the improvements were most pronounced when both the body and head received light, but there were still significant gains when only the body was exposed—affirming a systemic mechanism. These findings were statistically significant and consistent across participants.
Importantly, the implications go far beyond vision. This study supports the broader hypothesis that light-induced mitochondrial enhancement can be a systemic therapeutic tool. This idea is backed by a growing body of literature. A 2023 study showed that mitochondria can move between cells and even exist functionally within the bloodstream. Another 2023 paper from the Cell journal described “organellar crosstalk,” indicating that mitochondria in one organ can influence those in another, adding biological plausibility to the systemic effects seen in this light therapy research.
A practical takeaway from this research is the importance of regular exposure to full-spectrum natural light, which includes the near-infrared wavelengths that LED lighting often lacks. Regulatory changes aimed at increasing lighting efficiency may unintentionally reduce our exposure to these health-promoting wavelengths. Given the therapeutic potential demonstrated by near-infrared light in improving vision, metabolic health, immune function, and even cellular communication, it becomes critical to consider how modern lifestyles and indoor lighting environments may inadvertently be depriving us of a vital health resource.
This emerging science underscores a simple yet powerful message: our bodies are deeply responsive to light—not just for vision or circadian rhythms, but as a foundational regulator of mitochondrial health, systemic metabolism, and overall vitality. Reintroducing longer wavelengths through intentional exposure to natural light or therapeutic infrared light may be a low-risk, high-reward intervention to support human health and counteract chronic disease and aging.
LINKS / REFERENCES:
Longer wavelengths in sunlight pass through the human body and have a systemic impact which improves vision (Scientific Reports) | https://www.nature.com/articles/s4159…
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Melatonin and the Optics of the Human Body (Melatonin Research) | https://www.researchgate.net/publicat…