Understanding Infrared Light: The Foundation of Sauna Therapy
Before diving into how infrared saunas work, it’s helpful to understand what infrared light actually is—and why it feels so good.
What Is Infrared Light?
Infrared light is a form of invisible light energy that we feel as heat. It’s part of the electromagnetic spectrum, which includes all types of light energy, both visible and invisible.
Infrared means “below red”:
On the light spectrum, infrared waves sit just beyond visible red light—longer in wavelength, invisible to the human eye, but easily felt as radiant warmth.
The Light Spectrum: A Quick Breakdown
The electromagnetic spectrum is arranged from shortest wavelengths (high energy) to longest wavelengths (low energy):
Gamma rays: Extremely short, highly energetic, and dangerous
X-rays: Penetrating and also hazardous in high doses
Ultraviolet (UV): Makes up ~10% of sunlight; responsible for sunburns
Visible light: The narrow band of light we can see — from violet to red
Infrared (IR): Just beyond visible red, felt as heat but not seen
Microwaves and radio waves: Longest wavelengths on the spectrum
As we move from violet to red in the visible spectrum, wavelengths get longer and carry less energy. Red light, the longest visible wavelength (~700 nanometers), marks the boundary beyond which light becomes invisible to the human eye—and that’s where infrared begins.
How Infrared Light Interacts With Matter
Although we can’t see infrared light, we feel it every day. Infrared radiation is emitted by any warm object, including your body, the sun, and even a brick wall on a hot day.
Here’s an everyday example:
Stand next to a brick building that’s been baking in the sun. Even without touching it, you’ll feel heat radiating off the surface—that’s infrared energy being released.
Infrared energy works by being absorbed at the molecular level. When infrared waves penetrate a material—like skin, muscle, or even brick—they excite the molecules inside, causing them to vibrate and heat up. This internal warming is what makes infrared saunas so effective.
Infrared vs. Other Forms of Heat
There are only three ways humans experience heat:
Conduction – Direct contact (e.g., touching a hot pan)
Convection – Heat transfer through air or fluid (e.g., a hot breeze)
Radiation – Heat transfer via light waves (e.g., sunlight or infrared heaters)
Infrared heat = radiant heat:
It travels through air without needing to warm it first, targeting your body directly for deep, efficient heating.
That’s what makes infrared saunas so comfortable. Unlike traditional saunas that heat the air to extreme temperatures, infrared saunas warm your body directly, allowing for a deep, relaxing sweat at a much lower ambient temperature.
Infrared Light Is All Around Us
You experience infrared light more often than you think:
The sun emits about 50–53% of its total energy as infrared
Night vision goggles detect infrared radiation emitted from warm bodies
Hospital incubators use safe, far infrared heat to warm premature infants
Your own body is constantly emitting infrared light as thermal radiation
Infrared is natural, safe, and essential to life:
We feel it every day—especially when standing in sunlight or cozying up to a fire.
Bottom Line: Infrared Is Light You Can Feel
While visible light helps us see the world, infrared helps us feel it. Infrared saunas use this gentle, penetrating light to warm your body from within—stimulating circulation, enhancing detoxification, and supporting overall wellness.
And now that you understand how infrared works, it’s easy to see why it plays such a powerful role in modern sauna therapy.
