Why Pulsing is Counterproductive for Red Light Therapy - Red Light Hero

Why Pulsing is Counterproductive for Red Light Therapy

By
Helmut Uhlmann
First published
Last reviewed
Reading time
3 min read

In short

Pulsing comes from laser research, where switching the beam off for part of each cycle stops the tissue overheating. LEDs do not get hot the way lasers do, so there is nothing to protect - all a pulsed LED panel does is switch the light off for part of your session.

Most of the research used continuous light, and so do our panels.

Key takeaways

  1. The 2010 pulsing study that started the trend was done with lasers; its benefit is about letting lasers run at higher peak power without heating tissue.Read this section
  2. LEDs do not produce laser-level heat, so the OFF time that protects laser patients has no job to do in a panel.Read this section
  3. A 50% pulse means the light is off half the time: you need twice the session length for the same energy.Read this section
  4. Most photobiomodulation studies used continuous wave light, which is what HeroPanels™ deliver.Read this section
  5. Flickering light can entrain brain rhythms, but that needs no particular wavelength or power and is a separate thing from red light therapy.Read this section

Where the pulsing idea comes from

A lot of the pulsing hype derives from a 2010 study showing the positive effects of pulsing light, however this was done with lasers not LEDs. While studies show lasers produce similar biological effects, with no significant difference in outcomes, from a technical perspective lasers operate fundamentally differently to LEDs and produce far more heat which can even burn patients, with authors saying “because there are “quench periods” (pulse OFF times) following the pulse ON times, pulsed lasers can generate less tissue heating. This increased power can cause tissue heating at the surface layers and in this instance pulsed light could be very useful". Therefore the benefit of pulsed light refers to laser safety because you could treat a patient with "potentially much higher peak power densities than those that could be safely used in CW [continuous wave i.e. non-pulsed light]". But this is irrelevant to LEDs because they do not produce nearly the same heat as lasers and studies indicate that red light therapy is safe. There's simply no need to have an "OFF time" with modern LED red light therapy panels like our Hero Series.

Pulsing halves your dose

Further, were you to use pulsing in your red light therapy sessions, you would be unnecessarily halving the amount of light received in any given treatment period because half the time the lights would be off. This means you would need to treat yourself for twice as long to get the same total exposure time, wasting time and electricity.

What the research actually used

Finally, if you look through the photobiomodulation literature you will see most studies on red light therapy used continuous wave light.

This is why we opted to omit pulsing from Hero Series panels, passing on the savings to you. Pulsing is simply not necessary and, in our view, is even counterproductive.

An aside on brain entrainment

As an aside, pulsing light can also entrain the brain into alpha, delta and theta states visually, similarly to how binaural beats can do so through the auditory system. However this does not require any particular wavelength of light nor much power, you could even just use your phone screen for neural entrainment (certainly not worth upping the cost of the Hero300!). And in case you're curious, here are some free pure binaural beats for auditory entrainment (we find this a relaxing alternative to visual entrainment, just put it on headphones in the background at super low volume so you forget it's even playing).

References

Our sources for this article along with direct links and the reason we chose to cite it.

  1. Hashmi et al. (2010). Effect of pulsing in low-level light therapy. Lasers in Surgery and MedicineWhy we cite it: The review the pulsing claims trace back to. We quote its own explanation that pulsed lasers can run at higher peak power because the OFF periods limit tissue heating - a laser safety point, not an LED one.
  2. Effects of low-power light therapy on wound healing: LASER x LED. Anais Brasileiros de Dermatologia (2014)Why we cite it: A review comparing laser and LED light therapy, cited for the finding that the two produce similar biological effects.
  3. Wunsch and Matuschka (2014). A controlled trial to determine the efficacy of red and near-infrared light treatment in patient satisfaction, reduction of fine lines, wrinkles, skin roughness, and intradermal collagen density increase. Photomedicine and Laser SurgeryWhy we cite it: A controlled trial of full-body red and near-infrared LED treatment that reported on safety as well as results, cited for the safety of continuous LED exposure.
  4. Lee et al. (2021). Optimal flickering light stimulation for entraining gamma waves in the human brain. Scientific ReportsWhy we cite it: Shows that flickering light can entrain brain rhythms through the eyes - the aside about visual entrainment, which needs no particular wavelength or power.
  5. Binaural beats to entrain the brain? A systematic review of the effects of binaural beat stimulation on brain oscillatory activity (2023)Why we cite it: The review behind the comparison with auditory entrainment through binaural beats.

About the author

Helmut Uhlmann

Helmut Uhlmann

Founder, Red Light Hero

Helmut Uhlmann founded Red Light Hero and writes this blog. He delves deep into the research and is passionate about helping people get the most out of red light therapy.

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Disclaimer

Red Light Hero devices use clinical-grade LEDs but are not included in the ARTG and are not intended to treat or prevent disease. The research discussed here is about the wavelengths and technologies we use, not about our products. This article is educational information only, not medical advice - check with your healthcare professional before use, particularly if you are pregnant, take medication that increases light sensitivity, or have a condition affecting your eyes or skin.

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