Sunshine puts us in a good mood. There's no doubt about it. And the sun warms us up. This is where IR radiation comes into play. Unlike the UV rays that we often hear about, we can feel it. This is why it is often referred to as heat radiation.

If we briefly examine IR radiation in this article, discuss heat and heat radiation and you come to the conclusion, “Gee! Now we finally know the cause of sunburn”, we will quickly shout out, “Stop!”. Sunburn is caused by the invisible UV rays. IR rays provide heat, that’s true. But their effects on the body are different from sunburned skin.

Infrared radiation, the most important natural source being the sun, accounts for up to 50% of the solar radiation that hits our Earth. The Earth, in turn, emits infrared radiation after the sun has heated it. By the way, this is what all objects and bodies do, provided that they have a sufficient natural temperature of at least warmer than minus 273 degrees Celsius, which is absolute zero. 

IR rays are not visible but perceptible. Our body absorbs their energy and the molecules start to dance around. The result of this is heat. In other words, this is exactly the reaction we associate with the sun—it warms us. Although much of the absorption of infrared radiation (IR-B and IR-C) takes place on the surface of the skin (epidermis), the heat seems to manage to find its way effortlessly to the core of the body. Short-wave IR-A penetrates the subcutaneous skin. In addition, IR-A also makes its way into the retina of the eyes.

Infrared rays are used in medicine and industry. Muscular and back problems can be treated using IR due to its warming effect, for example, in so-called infrared cabins or using special IR lamps. However, a doctor should assess whether such a treatment is suitable for you and recommend suitable applications. 

One example of a technical application is the use of thermal imaging cameras. These cameras, also known as infrared cameras, give bodies that radiate heat a different color so they can be identified. Using night vision devices, you can detect people in complete darkness, for example. Modern clinical thermometers also use IR for contactless body temperature measurement.

Skin damage also caused by IR? 

But back to the sun’s IR rays. Even though the warmth is good for you, it is also true that too much of it is too much. In addition to sunstroke, there are other forms of heat damage that can stress and injure the body. Read about what can happen if you absorb too much IR radiation in our article about the body’s reactions here.

Although IR radiation does not cause sunburn, we still need to protect ourselves from it. In this case, however, we can't rely on the usual sunscreens and creams for protection. It’s more about protection through avoidance. Wear clothing, a hat, stay in the shade or a cool room, and make sure you drink plenty. It is not a good idea to walk around in the strong midday sun at lunchtime unless you have to. And take care of your eyes as well. Looking directly at the sun can be harmful, especially due to the enormous brightness in the visible range and also due to infrared radiation. 

We have pointed out the dangers of UV radiation for the skin many times. For years, researchers and scientists have also been studying the effects of infrared on the skin. Some  research suggests that short-wave IR-A rays penetrating deep into the skin can cause changes, free radical formation and oxidative stress. The result is damaged cells and increased collagen degradation. However, the mechanism of action seems to be different compared to UV. Instead of UV filters, antioxidants are required to minimize damage.

And just like with UV protection: Enjoy the sun, but watch how much time you spend in it and your exposure.