For Those Who Need to Know the “Why”

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Wait...Our Cells Respond to Light?

They do.

And this is where photobiomodulation becomes fascinating.

Humans have been interacting with light for as long as humans have existed.

Light helps regulate our sleep-wake cycle.

Sunlight allows our skin to produce vitamin D.

And specific wavelengths of light can interact with molecules inside biological tissues.

Photobiomodulation takes advantage of that last part.

Instead of using light primarily to heat, cut or destroy tissue, PBM uses carefully controlled light energy intended to change biological activity.

Hence the name:

Photo = light

Bio = biology

Modulation = changing or influencing something

Photobiomodulation literally means:

Using light to influence biology.

That's refreshingly accurate for a medical term.

Meet the Mitochondria

If you remember one thing from biology class, it may be:

“The mitochondria are the powerhouse of the cell.”

Your teacher wasn't lying.

Mitochondria help convert energy from nutrients into ATP, a form of energy cells can actually use.

Muscle contraction requires energy.

Nerves require energy.

Repair requires energy.

Pretty much everything your cells do requires energy.

And mitochondria appear to be one important target of photobiomodulation.

Cytochrome c Oxidase

Inside mitochondria is an enzyme called:

cytochrome c oxidase.

We'll call it CCO.

Your brain has enough to remember already.

CCO participates in the mitochondrial electron transport chain involved in ATP production.

One leading model of PBM proposes that red and near-infrared light can interact with chromophores including cytochrome c oxidase.

That interaction may influence mitochondrial activity and cellular signaling.

But here's where things get even more interesting.

Researchers now believe PBM's effects probably involve more than one mechanism.

Light may influence:

• Mitochondrial activity

• ATP production

• Nitric oxide signaling

• Reactive oxygen species signaling

• Gene expression

• Inflammatory pathways

• Blood flow

• Cellular repair processes

So PBM isn't simply “giving your cells more energy.”

The biology appears to be much more complicated than that.

It usually is.

Red Light vs. Near-Infrared Light

Not all light behaves the same way in the body.

Different wavelengths interact differently with tissue.

PBM commonly uses wavelengths in the:

Red spectrum

and

Near-infrared spectrum.

Red wavelengths tend to have more superficial penetration.

Near-infrared wavelengths can generally penetrate farther into tissue.

That means the wavelength we choose should depend partly on what we're trying to reach.

Treating a superficial structure and attempting to influence deeper tissue aren't necessarily the same job.

Wavelength Isn't Enough

Here's one of the biggest misunderstandings about PBM.

People often ask:

“What wavelength does your laser use?”

That's a good question.

It just isn't the only question.

We also need to know:

Power

How much optical power is the device producing?

Irradiance

How much power reaches a given area?

Energy

How much total light energy is delivered?

Energy Density

How much energy is delivered per unit of area?

Treatment Time

How long is the tissue exposed?

Distance

How far is the light source from the tissue?

Continuous or Pulsed

Is the light delivered continuously or in pulses?

Treatment Location

What tissue are we actually trying to influence?

All of those can matter.

This is why two devices that both say:

“810 nm near-infrared”

may not provide the same treatment.

More Is Not Always Better

This is one of the coolest parts of PBM.

With many treatments, people assume:

If some is good, more must be better.

Biology frequently disagrees.

PBM appears to demonstrate what researchers call a biphasic dose response.

Too little light may not create the desired biological response.

An appropriate dose may help.

But increasing the dose beyond the useful range doesn't necessarily create a bigger benefit and may reduce the desired effect.

Think about exercise.

Zero exercise isn't ideal.

An appropriate workout can be helpful.

Doing squats continuously for eleven hours is not eleven times healthier.

Dose matters.

What Can PBM Be Used For?

Photobiomodulation has been studied across a surprisingly large number of areas.

Research includes applications involving:

Musculoskeletal Pain

PBM has been investigated for conditions involving muscles, tendons and joints.

Tissue Repair

Researchers have studied PBM in wound healing and tissue-repair processes.

Inflammation

PBM can influence cellular signaling pathways involved in inflammatory responses.

Nerve Function

PBM has been investigated for peripheral nerve injury, neuropathic conditions and neural recovery.

Oral and Dental Applications

One of the more established clinical applications involves preventing or treating oral mucositis in certain cancer-treatment populations.

Neurological Applications

Transcranial photobiomodulation is being investigated for:

• Cognitive function

• Brain injury

• Depression

• Neurodegenerative conditions

• Cerebral blood flow

• Other neurological applications

This research is particularly exciting.

But many neurological applications are still emerging rather than established standard treatments.

Can Light Really Reach Deep Tissue?

Yes—but with an important catch.

As light enters the body, some is:

• Reflected

• Scattered

• Absorbed

That means the amount of light reaching a deeper structure is much lower than the amount leaving the device.

Wavelength matters.

Tissue type matters.

Skin pigmentation can matter.

Body composition can matter.

Treatment location matters.

And depth matters.

This is why:

“The laser produces X joules”

doesn't automatically tell us how much energy reached the tissue we're interested in.

That's also why proper dosing matters.

Laser vs. LED

PBM can be delivered using both:

Lasers

and

LEDs.

A laser produces coherent, directional light.

LEDs produce noncoherent light over a broader area.

Both can produce photobiomodulatory effects when appropriate wavelengths and doses reach the target tissue.

So the important question isn't simply:

“Is it a laser?”

The better question is:

“What light are we delivering, how much are we delivering, and what are we trying to accomplish?”

What About Our Lasers?

Our office uses photobiomodulation devices as tools within a larger treatment plan.

We don't use the laser simply because:

“Laser sounds impressive.”

We choose the treatment area and protocol based on what we're trying to accomplish.

Depending upon the patient, PBM may be used alongside:

• Chiropractic care

• Neurological rehabilitation

• Movement therapy

• Soft-tissue treatment

• Exercise

• Nutritional support

• Other appropriate therapies

PBM is rarely the entire story.

It's one tool in the toolbox.

A very cool-looking tool.

But still a tool.

What Does the Research Say?

Photobiomodulation has been studied for decades.

Thousands of laboratory, animal and human studies have investigated the biological effects of red and near-infrared light.

Systematic reviews and clinical trials support PBM for certain applications.

Other applications have promising early evidence.

And some uses remain largely theoretical.

This is important because there is no single scientific answer to:

“Does red-light therapy work?”

That's like asking:

“Does exercise work?”

For what?

What kind?

How much?

How often?

For whom?

PBM needs the same questions.

A properly dosed treatment for one condition cannot automatically be assumed to work for another condition simply because both involve the same color of light.

Our Approach

We keep PBM treatment focused.

1. Identify the Goal

What are we trying to change?

Pain?

Movement?

Tissue healing?

Neurological function?

Recovery?

Something else?

2. Identify the Target

What tissue or neurological structure are we attempting to influence?

3. Select the Device

Different PBM devices have different wavelengths, powers and treatment characteristics.

4. Determine the Dose

Choose treatment parameters appropriate for the target and therapeutic goal.

5. Apply the Treatment

Deliver the light to the intended treatment area while following appropriate safety procedures.

6. Reassess

This is the part we don't skip.

Did pain change?

Did movement change?

Did swelling change?

Did neurological function change?

Did the patient's functional ability change?

And over repeated treatments:

Are we actually moving toward the patient's goal?

What Are We Trying to Accomplish?

Photobiomodulation isn't about shining a fancy red light on someone.

It's about using a measurable form of energy to create a specific biological stimulus.

Sometimes we're interested in pain.

Sometimes inflammation.

Sometimes healing.

Sometimes nerve function.

Sometimes neurological performance.

The treatment changes because the goal changes.

And that's exactly how it should be.

Right light.

Right place.

Right dose.

Right reason.

Then we measure what happened.

Because the coolest technology in the building is only useful if it helps the person we're treating.