3Discussions
144 minAnalysed
Last reviewed: Jul 14, 2026·Credential: MD; board certified in internal medicine, pulmonary disease, critical care medicine and sleep medicine; associate clinical professor, UC Riverside School of Medicine·First indexed: Jul 14, 2026
About the expert
Focus: Argues that infrared light from the sun acts on mitochondria to improve energy production, and that modern indoor life filters out a wavelength the body uses.
Roger Seheult is a practising ICU and pulmonary physician who is board certified in internal medicine, pulmonary disease, critical care and sleep medicine. He co-founded MedCram, a medical education platform used widely by clinicians and students, and became well known during COVID for walking through primary literature in detail. In recent years he has focused on sunlight and infrared light exposure as an underexamined input to health, drawing on the photobiomodulation research field.
Expert discussions with Dr Roger Seheult
Do you need sunlight even if you take vitamin D?
Infrared light makes up a large share of the sunlight reaching us, and unlike ultraviolet it passes through clothing and deep into tissue. The claim is that it reaches the mitochondria and helps them make energy more efficiently. The research field is real, but the human evidence is a handful of small trials, and the mechanism offered to explain them is the speaker's own hypothesis rather than published work.
Should you let a fever run its course?
A fever in an otherwise healthy adult is not the illness. It is part of how your body fights one, and bringing it down every time may work against that. Children, older adults and anyone seriously unwell are a different question. Several other rules turn out the same way: more exercise is not better, and a supplement rarely replaces what your body makes itself.
What actually keeps you from getting sick?
Getting sick less is mostly the same work as living longer, so there is no separate immunity trick. Sunlight, sleep, moderate movement and unprocessed food carry most of it. The framework he uses to organise those comes from a faith tradition, which is worth knowing before you weigh the last pillar.