Longer wavelengths in sunlight pass through the human body and have a systemic (nature.com)

A study in Scientific Reports finds that near-infrared wavelengths in sunlight (about 830–860 nm) can penetrate through the human thorax, including when blocked by clothing, and remain detectable after passing through the body. In a lab experiment, 15-minute exposures of this wavelength range improved measures of visual function 24 hours later, even when light was prevented from reaching the eyes. The authors attribute the effect to mitochondria-related changes in energy production and argue this supports a broader, system-wide influence of longer-wavelength sunlight.