The Science Behind Infrared Heat: Why It Hits Different
Wellness science
The Science Behind Infrared Heat: Why It Hits Different
By Aura Saunas · 6 min read
You’ve probably heard that infrared saunas are different from traditional ones. But when people ask how, the answer usually stops at “lower temperature, deeper heat.” That’s true — but it’s only half the story.
Infrared saunas use light in the infrared spectrum — wavelengths just beyond visible red light — to heat objects directly rather than the surrounding air. Your skin and subcutaneous tissue absorb this energy, raising your core body temperature from the inside out. The result is a deeper, more penetrating heat at ambient temperatures between 120–150°F, versus the 180–220°F required in a traditional Finnish sauna to achieve similar physiological effects.
What’s actually happening in your cells
When infrared energy penetrates tissue, it triggers a cascade of biological responses. Mitochondrial activity increases — your cells’ energy factories begin working harder. Heat shock proteins (HSPs) are produced, which repair damaged proteins and protect cells from stress. Blood vessels dilate significantly, increasing circulation by up to 30% and delivering oxygen and nutrients to muscle tissue at an accelerated rate.
Key research finding
A 2018 study published in Evidence-Based Complementary and Alternative Medicine found that regular far-infrared sauna use reduced fatigue, improved sleep quality, and decreased pain scores in participants with chronic fatigue syndrome — after just four weeks of use.
Near, mid, and far: the full spectrum explained
Full-spectrum infrared saunas — like our Aura Elite and Solstice models — emit all three wavelength ranges. Near-infrared (NIR) penetrates shallowest and is most associated with skin health, collagen production, and wound healing. Mid-infrared (MIR) reaches deeper into soft tissue, supporting cardiovascular function and pain relief. Far-infrared (FIR) penetrates deepest, reaching joints and internal organs, and is most associated with detoxification and immune support.
The cardiovascular connection
One of the most compelling bodies of research around sauna use comes from Finland, where the KIHD study tracked over 2,000 middle-aged men for 20 years. Those who used saunas 4–7 times per week had a 40% lower risk of all-cause mortality compared to once-a-week users. The mechanism? The cardiovascular workout that heat provides — your heart rate climbs to 120–150bpm during a session, mimicking the effects of moderate aerobic exercise.
How to get the most from your sessions
Consistency matters more than duration. Two 20-minute sessions four times a week will outperform one hour-long session on a Sunday. Start at lower temperatures (125–130°F) and work up gradually. Always hydrate before and after. And resist the urge to check your phone — the stillness is part of the medicine.