Why Sunlight Heals: An Intro To Heliotherapy


By Jes Williams @feelmoregooder

What is Heilotherapy? I spent years learning about heliotherapy, but I’ll break it down for you in some smaller, digestible bites in this blog post. Heliotherapy is also sometimes used interchangeably with photobiomodulation and phototherapy.

Heliotherapy (helio = sun, therapy = treatment) is the use of mindful sun exposure to treat illness. Use of sunlight therapy dates back to over 3500 years ago in Ancient Greece, Egypt, India and China back in the 15th century BC. However, sunlight therapy is widely credited to Dr. Auguste Rollier & Dr. Niels Finsen.

Heliotherapy in Ancient Times

Many ancient cultures practiced solarization. Greek Historian Herodotus wrote that the “sun feeds muscles”, over 2,000 years ago. He also attributed sunlight deprivation to weak & brittle bones, and recommended sunlight for “weak and soft muscles.”

Moreover, the citizens of Rome had right-to-sunlight legislation. This is how important the Romans considered sunlight. They commonly had solariums and sunning terraces built as a part of their home.

Egyptians were known to shave their heads from childhood to increase sunlight into the skull. Not coincidentally, baldness is more rare in Egypt than anywhere else. The increase of melanin in the skin also impacts hair pigmentation and combats premature graying.

“The sun has long been viewed as an object of amazement and reverence for various cultures throughout history. Dozens of ancient societies have worshipped the sun as a source of life and nourishment, and many designed their temples specifically to let in sunlight. The Chinese introduced the art of morning sun gazing, integrating it into exercises such as tai chi. Even yoga has strong ties to sun exposure; the sun salutation originates in India as part of an old Hindu practice. In addition to worshipping the sun god Ra, the ancient Egyptians were the first to report health benefits of sun exposure as early as 6000 years ago. Ancient Greek, Roman, and Arabic civilizations similarly recognized its therapeutic value. This global appreciation of the sun as a source of health has since permeated into western medicine.”

Sun Exposure in History – Stephanie Mlacker BS, et al.

Dr. Auguste Rollier & Niels Finsen

Dr. Auguste Rollier & Dr. Niels Finsen are both acknowledged as pioneering the treatment known as heliotherapy. Dr. Auguste Rollier opened the world first Sun Clinic is the Swiss Alps of Leysin, Switzerland in 1903. These clinics were solarium-style hospitals located at high altitudes - where Rollier also utilized the therapeutic effects of cold exposure, fresh air, and higher UV. Rollier said, “ The sun is the best masseur.”

He went on to open 37 heliotherapy clinics. By 1930, there were 3,000 patients being seen at one of Dr. Rollier’s clinics in Leysin, Switzerland. These patients' school, work, healing, and leisure activities were all done in the sun under the doctor's supervision.

Recovery from tuberculosis and rickets using this therapy were his specialty. A notable feature of this therapy is that Rollier found that his patient’s treatment was ineffective if they wore sunglasses. This makes sense when you consider the importance of the eyes (an extension of the brain) and the receptors they contain for interfacing with light.

Dr. Auguste Rollier's practice was inspired by the work of Dr. Niels Finsen, who won the Nobel prize for his own discoveries with heliotherapy in 1903. Helping to pioneer the modern heliotherapy movement, Dr. Niels Finsen became curious about using the sunlight to improve his health, as his residence only had north-face windows and he suffered from Pick's disease. North-facing windows receive the least amount of light, as the sun's path would never penetrate through a window from that direction. This curiosity and experimentation about increasing light exposure led to Finsen's remarkable studies and work in heliotherapy.

Oskar Bernhard

Around the times of Dr. Rollier & Dr. Finsen, Dr. Oskar Bernhard was helping patients using heliotherapy in Samaden, Switzerland. Dr. Bernhard built up a substantial surgical practice where he helped to establish the District Hospital at Samaden. As surgeon-in-chief, Bernhard treated surgical tuberculosis with open-air methods, nutrition therapy and orthopedic measures from the 1880s on.

He, too, began to use sunlight to heal wounds and treat tuberculosis. Dr. Oskar Bernhard was also nominated for the Nobel Prize in (Physiology or Medicine) 6 times between 1920 and 1932, but he was never named the winner.

Vitamin D3

Part of the therapeutic benefit of sunlight is linked to vitamin D3.  In the 1920s, researchers began to understand the relationship between sunlight and vitamin D. Specifically, it was observed that children with rickets, a disease caused by vitamin D deficiency, showed significant improvement when exposed to sunlight.

As is common knowledge now, sunlight exposure is crucial for the production of vitamin D3. When ultraviolet B (UVB) rays from the sun penetrate the skin, they convert 7-dehydrocholesterol to previtamin D3, which is then transformed into active vitamin D3 (cholecalciferol). This process is essential as vitamin D3 enhances the absorption of calcium and phosphorus in the intestines, promoting bone health and reducing the risk of osteoporosis. Additionally, adequate vitamin D3 levels support the immune system, potentially lowering the incidence of autoimmune diseases and infections. Moreover, sunlight exposure has been linked to improved mood and mental health, possibly due to the increased production of serotonin, a neurotransmitter associated with feelings of well-being and happiness.

Heliotherapy Today

In 2024, this movement is making a resurgence. There are strong voices in both the medical and holistic health world who are educating on this topic and reminding us all about the therapeutic benefits of sunlight. Some of the big voices to look into are Dr. Jack Kruse, Dr. Martin Ettinger, Dr. Catherine Clinton, Kiera Lea, Dr. Max Gulhane, and many more.

The implications of this cultural return to nature have the potential to change the tide of health for all of us. Nature and a close relationship with it offer us systemic support, and it's about time we get curious about how nature can help us restore and maintain health.

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