In one sentence, light works through activating neuro-endocrine (through the eyes) and photosensitive (eg. through the skin) processes in the body. However to understand how light therapy works, we must first understand what light is. To define it in a few words we would have to call light - electromagnetic radiation. Since this term doesn't mean very much to most of us, we need to explain it in more common language. A ray or particle of light can be thought of as a mixture of electricity and magnetism. Most light also has a bit or infra-red radiation (heat) incorporated into it. Here is a spectrum of the wavelengths of electromagnetic radiation contained in sunlight:



Our eyes are only capable of seeing about 50% of sunlight which is the visible light portion. The remaining two portions of the sun's radiation we can feel as heat, but we cannot see. Thus energy (UV and infrared in this case) which is invisible can also affect us. We know that if we sit in the sun without sunscreen, the UV rays will give us sunburns. Radiation is a term used to describe any form of energy which can travel through space without an intervening medium. Sound needs to cause vibrations in the molecules of air (or water in the case of fish) to be able to travel from the speaker to the receiver. Thus sound is not a form of radiation. Light however travels from the sun, through thousands of miles of space to reach the earth without any intervening medium - space is a vacuum with no particles. Once the light reaches our planet the atmosphere filters out some of the energy out of the light (some UV radiation for example) while the rest continues to reach the Earth's surface. Thus light is stopped by any form of atomic obstruction, whether it is a gas or a solid. Think of using a flashlight on a clear night and then consider using it on a misty night. The light from your torch wouldn't carry very far through the mist. So light can be thought of as a transfer medium, it can transfer specifically tuned energy from the source to a receiving atom, molecule, object or organism without losing much of the information along the way.

It is common knowledge that light is a form of energy, powering solar devices for example. What is less known is that everything surrounding us is also energy. Believe it or not all the matter around us is also energy - in its frozen form. If a piece of wood is put on fire, it will burn, and release energy in the form of heat. Without that initial spark however the energy was trapped in the wood. Energy has trouble staying in one place 100% of the time, so it is in a dynamic equilibrium all the time. In an atom, while one electron spins one way, another would spin in the exact opposite to balance it. Then the first electron would change direction completely and be balanced by another electron which happens to be traveling in its current opposite. Thus even on the most basic level, even the most solid things vibrate. This movement is so small that hardly any device can detect it, but it is present. Now lets imagine that this atom was in a piece of wood, and an axe comes along and chops this piece of wood in half. The atoms must adjust to this physical change while still remaining perfectly balanced. Or if the wood burns, the atoms must still adjust to that change, otherwise they would become unstable and cause an enormous, uncontrolled release of energy. To paint a picture of the scale of atomic energy, a golf-ball sized piece of plutonium metal (considering 100% of its energy is harnessed) can cause a nuclear blast the size of Hiroshima. In 1997 at the University of Rochester by means of lasers, enough energy to run an entire nation was concentrated into a millionth of a meter for a trillionth of a second. This intense energy was then barreled at a stream of electrons. When the electron collided with a photon at such tremendous speed, it caused the photon to collide with a few more of these dense photons behind it as well. The result was that the photon-photon collisions created an electron and a positron. Thus it was proved that energy can create basic elements of matter.

Just like all matter, the human body is also in a state of dynamic equilibrium. In a far more complex equilibrium however than the simple one explained before. We are a mix of gases, chemicals, liquids, fluids and solids. All of these are constantly undergoing change, food being digested to create fuel to exercise, calcium being added and removed from bones, muscles contracting and relaxing, gas exchange in the lungs . . . All of these processes inter-relate and together they form our body. These processes interchange chemical energy all the time and thus can be easily affected by incoming sources of energy. Heat can cause an enormous physiological response from the body. In this same manner light can be applied to elicit the appropriate response from the body - different of course from that of heat, as it is a different form of radiation.

The recent advances in physics have allowed a number of German physicists to detect the tiny amounts of light emitted by living cells. They termed this field of study biophotonics - the study of biophotons or the study of photons emitted by biological cells. It has also been proven that cells can communicate via these biophotons, which also means that they can not only emit light - they can receive light. Thus every living cell can accept light which is aimed at it. Considering that cells emit extremely minute amounts of light which our eyes cannot see, then providing the cell with normal amounts of light can have profound effects on it. This statement shouldn't be understood that light is a magic bullet to cure every disease, instead it should be thought of as a general source of energy from which a cell can mix and match which wavelengths of light it requires. White light contains the full spectrum of colours, thus the cell can select which amount and type of energy (wavelength/frequency) it requires to balance itself. Light therapy is also a very gentle treatment which works over time - not all at once, however it is additive such that once it takes full swing the effects are long lasting even when the therapy has stopped