Laser stands for Light Amplification by Stimulated Emission of Radiation. Laser light is composed of photons that move in ordered wavelengths unlike otherwise bright. The technology creates single-color light rays in phase and has a direction and a strong intensity. There are primarily two different classes of lasers in medicine today. Class 4 and class 3B.


  • Wavelength = nanometers, nm
  • Output = milliwatts, mW
  • Overall energy amount = Joule, J


Class 4

used in surgery and is called the strong laser. It has a thermal capacity which allows it to burn and cut.

Class 3b (LLLT)

Often referred to as terapeutisk-, medical, low-power or biostimulative laser. During 500mW per diode and stimulates cell function. Anyone may use 3b and the man primarily is looking for is to relieve pain and promote healing by stimulating the photochemical reactions in the body through different receptors, by laser.

Mechanism of action


The most studied receptor in laser therapy are the mitochondria and called cytochrome c oxidase. It stimulates nitric oxide (NO) which in turn regulates the production of ATP, and acts as a vasodilator neurotransmitter. It thus ATP and circulation increases, allowing the cell function is normalized / optimized. The metabolism increases, one can also say.

  • vasodilates vessels
  • Increases the amount of ATP
  • The cell’s metabolism increases


It is believed that the laser interacts with the interleukins (affecting white blood cells) and cytokines / inflammation factors to achieve its anti-inflammatory effect. It is sometimes seen that the laser has a better anti-inflammatory effect than drugs.

  • Affects the white blood cells (immune system)
  • Affects cytokines / inflammatory factors


It is believed that laser therapy analgesic effect partly due to that by the laser selectively inhibit certain neural pathways, Adelta and C fibers. They are nociceptors sending afferent signals to the spinal cord for pain, then the signal is inhibited think that it provides an analgesic effect.

It is also believed that reducing oxidative stress in the muscles during treatment with the laser. With oxidative stress is meant the internal chemical imbalance which produce too much harmful oxygen or free radicals.

  • Roll A-delta and C fibers (send pain signals to the spinal cord)
  • Reduces oxidative stress in the muscles

General guidelines on wavelength with medical lasers

Optimum optical window for the laser is 600-1070nm. If you have a shorter wavelength than that absorbed by melanin and hemoglobin. Longer wavelengths in laser provides a deeper penetration and one can thus get deeper.

At the superficial structures are sought 600-700nm and 780-950nm deeper structures. It has also been seen to wavelengths between 700-770 does not have any biological effect, that this should span avoided.

  • Optimal window 600-1070nm
  • Superficial 600-700nm
  • Deeper structures 780-950nm
  • NOTE. 700-770nm have not seen any effect

General advice for the therapist to give patients the treatment with laser

The thinking of the laser is that we give the body conditions to heal itself, as we increase metabolism at the cellular level, which then reduces pain and promotes healing. It is after a laser treatment experience a “Superhero” effect ie you think it feels so good to be running at full and pulls up the injury worse. You can also feel the occasional fatigue alternatively get increased pain between 6-24h after treatment, it should be seen as an indication that they have hit with the laser.

Indications for laser treatment

  • not painful
  • Suitable for acute disorders and inflammation
  • Wide range for which diagnosis treatable
  • Almost no risk
  • Pain relief is relatively instantaneous

Contraindications for laser treatment

  • Malignancy / treated for cancer to … ??
  • Epilepsy to …?
  • Pregnant to …?
  • Light sensitive and fair skin as reddish.
  • Corticosteroid use for?
  • Fever for?
  • Infection for?
  • Hyperthyroidism for?
  • Heavy blood loss to?

Extra caution during treatment with laser

When there is a risk of burns. This risk is such of dark skinned individuals or dark pigment / liver spots. These generate heat and can cause burns. One should also take into account the tattoos, there is a risk that even the heat or to “wear” on the tattoo.

  • Dark skin
  • Dark pigment or liver spots
  • tattoos

Summary laser

  • Many studies on the laser has had the opposite results regarding the effect of laser treatment. It is believed that this is because the laser therapy is very sensitive to the method used. It is important to set the right diagnosis, the right wavelength, length of treatment and the strength of the laser.
  • Low dose = promote healing
  • High dose = reduce pain or inflammation
  • The depth of the structure to treat determine what dose you need, different tissues absorb different amounts of light.
  • Heat is not the main reason for the reaction
  • Stimulates photochemical reactions in the body
  • There are different receptors for light or photons.
  • There are different receptors for light or photons.
  • The most studied are the mitochondria and called cytochrome c oxidase