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Infrared Heat Lamps vs. LED Photobiomodulation (Light Therapy) Devices


Infrared Bulb vs LED Therapy

You’ve probably seen them at a local home improvement store.  The red heat bulbs that sell for less than $10.  Are these just as good as LED-based light therapy (photobiomodulation) devices?    

It’s a great question and one that often comes up during interactions with our customers.  After all, it would be ideal if you could get great results from a $10 heat lamp from the local Home Depot, right? 

Admittedly, to answer this question, it can be confusing since there are quite a few companies that claim their products produce cellular health benefits using nothing more than 250-watt incandescent heat lamps.  But sadly, many misinformed consumers are tricked by deceptive marketing and junk science.  They end up purchasing these devices, which can sell for over $1,000, only to later realize they aren’t effective.  

Before making the same mistake, let’s take a look at the science to determine if these infrared heat bulbs can actually be used to generate the same type of benefits that have been proven across hundreds of photobiomodulation (PBM) studies.

How Does Photobiomodulation (PBM) Work?

At its most basic level, by delivering specific wavelengths of light to human cells, a photochemical effect is produced, which boosts intracellular mitochondrial function.  This results in a wide variety of benefits derived from enhanced ATP (adenosine triphosphate) production.  Extensive published research has demonstrated that specific wavelengths have the greatest positive effects on cellular processes.(1)  In fact, as we've discussed before, the ranges that have been proven to be most effective are from 630 nm to 670 nm, and from 810-880 nm.

Another critical factor, in terms of producing optimum cellular benefits, is the intensity - or irradiance - of the light source.  Research has shown that the total energy delivered typically needs to be 4-5 Joules/cm2 at a minimum.  Some clinical studies have even shown that higher amounts, approaching 100 Joules, are needed in order to treat deeper tissue.  The intensity of the light directly impacts the time required for treatments.  For example, a device with 1/3 the irradiance would take 3 times as long to get the same results.  Imagine filling up your water bottle from a dripping faucet.  Yes, you will eventually fill it up, but you’ll waste a lot of time in the process. 

For these reasons, clinical grade irradiance of 50-100 mW/cm2 is ideal.  This range equates to 3-6 Joules/cm2 per minute.  Lower-powered devices in the 5-10 mW/cm2 will technically work, but like the slowly dripping faucet, it will take a very long time to receive the necessary amount of light energy.

Wavelengths of IR Heat Lamps

How Does a 250 Watt Heat Lamp Work?

Infrared (IR) heat lamps produce a wide range of wavelengths.  As you can see in the chart above, starting around 600 nm, the curve builds to its peak output at around 1100 nm.(2)  Less than 1% of the energy is delivered from 600-660 nm; and only about 2% is delivered in the entire 810-880 nm range.  So, in total, these wavelengths only represent about 3% of the total energy delivered by the bulb.  You might ask, but what about the other wavelengths, aren’t they beneficial too?  Fantastic question!

For the purposes of cellular function, the answer may surprise you.  Wavelengths in the 700-750 nm range, for example, have been shown to produce essentially no effect on mitochondrial activity.  This is reflected in the graph below, which shows cytochrome c oxidase (CCO) absorption at various wavelengths.(3)  And as we’ve discussed previously, CCO activation is crucial when it comes to experiencing the benefits of photobiomodulation.  So, in summary, all wavelengths are NOT created equal with respect to light therapy. 

How Red and NIR Light Activate Cytochrome C Oxidase

What About the Intensity of 250 Watt Heat Lamps?

Since these types of bulbs produce a lot of heat, many assume they deliver intense light.  The reality may surprise you.

As you can see in the graph below, at a distance of 20 cm directly in front of the bulb (about 8 inches), the total irradiance is about 320 mW/cm2.(4)  Remember, only about 3% of the light energy delivered through these types of bulbs is biologically effective.  So, using 320 mW/cm2 as a baseline, 3% of the energy would represent less than 10 mW/cm2.  And that is just directly in front of the bulb!  At 10 cm, or just 4 inches off-center, this value drops to less than 2 mW/cm2.  To put that in perspective, if you were using this on your face, your nose would get about 5 Joules in a little over 8 minutes (presuming you could stand the heat), while your chin would get less than 1 Joule.  In comparison, the smallest Joovv Light Mini, in the combo configuration, delivers 100 mW/cm2 - or 6 Joules/cm2 per minute - over an area of 12” x 20”. 

Intensity of IR Heat Lamps at Different Distances

When it comes to efficiency, because of their narrow-band output, LEDs produce very little heat.  On the flip side, the tungsten filament inside infrared heat lamps can increase to 5000 degrees F, which results in high amounts of radiant heat delivered from the surface of the bulb.  The type of heat produced by infrared lamps will result in oxidative stress that is counterproductive to photobiomodulation, and in some cases, can even lead to severe burns. 

In Summary, Infrared Heat Lamps are Not Ideal for the Purposes of Light Therapy

So, while infrared heat lamps create a fair amount of radiant heat across a wide range of wavelengths, for the purposes of light therapy, they are essentially useless.  For that reason, LEDs or lasers are used in virtually all published clinical research in the field of photobiomodulation.  Increasingly, over the past decade, LEDs have become a popular option because of their low cost and ability to treat larger surface areas.  So, in your search for the best light therapy device, make certain the product delivers the right wavelengths with medical-grade intensity that aligns with the hundreds of clinical studies that have been published over the last few decades.

References:

(1) Hoon Chung, Tianhong Dai, Sulbha K. Sharma, Ying-Ying Huang, James D. Carroll, and Michael R. Hamblin. The Nuts and Bolts of Low-level Laser (Light) Therapy, Ann Biomed Eng. 2012 Feb; 40(2): 516–533.

(2,4) Phillips.  Infrared heat lamps/industrial product specification. http://images.100y.com.tw/pdf_file/21-PHILIPS-InfraredHeatLamp.pdf

(3) Karu, T. I., Pyatibrat, L. V., Kalendo, G. S. and Esenaliev, R. O. (1996), Effects of monochromatic low-intensity light and laser irradiation on adhesion of HeLa cells in vitro. Lasers Surg. Med., 18: 171–177.