Light therapy has been used for more than two decades to treat circadian rhythm (body clock) disorders. Every living thing has an internal clock that tells it when it is time to be asleep and when it is time to be awake. Humans are by diurnal (day orientated) beings, meaning that our physiological functions are geared towards day time activity and night time rest.
The area where this is controlled is located in the brain and is called the suprachiasmatic nucleus or SCN. Your body clock controls the ‘circadian rhythms' in your body.
These rhythms include body temperature, alertness and the daily cycle of many hormones and occur in a cycle of about 24 hours. Circadian rhythms make you feel sleepy or alert at regular times every day.
If your body clock is not working as it should you will find that everyday tasks take longer to complete, you may be lacking in energy and craving sweet or starchy foods. Some people experience a change in their sleep patterns, for example, you might sleep two extra hours each night during the winter months, and yet still feel tired.
Your body clock is ‘set' by your exposure to a bright light source such as sunlight, if that is not available then exposure to ‘light therapy' is the next best thing. Light therapy can help ‘re-set' your body clock.
Until recently the symptoms of S.A.D. have been thought to be an exclusively winter problem. However, in recent years the boundaries are becoming blurred as more buildings are being built with tinted glass and internal offices without any windows. People are now experiencing the problems of circadian disturbances all year round.
Light therapy is used to expose your eyes to intense but safe amounts of light for a specific length of time. A lightbox may be used to influence the body clock in the same way that sunlight does.
New advances continue to be made in the field of Light Therapy.
So what can lightboxes be used for as well as S.A.D.?
1. Energy Levels
Lightbox can help increase you energy levels when you cannot get out into natural sunshine. If your office has little or no natural light you could be depriving your body of a vital nutrient.
2. Sleep Disorders
The lightboxes are used to reset the body clock (circadian rhythms). Lightboxes are used at many of the leading Sleep Disorder clinics in the UK.
3. Jet Lag
Lightboxes are very effective in resetting the body clock after travel.
Travelling East (from the UK) you should advance the body clock. The number of time zones corresponds to the number of hours you need to change. When you arrive it is better to avoid bright light to encourage the build up of melatonin to help you sleep, and take the bright light in the morning to wake you up.
Travelling West (from the UK) before you travel, you can delay the body clock by using extra light in the evening. On arrival use bright light in the afternoon and evening to postpone bedtime and then again in the morning to wake you up.
4. Shift Work
This sleep disorder occurs due to a work schedule, such as night shift, that takes place during the time when most people are sleeping. This requires you to work when your body wants to sleep. Then you have to try to sleep when your body expects to be awake. Changing work patterns, days off, and social activities can alter your exposure to light from day to day.
Frequent changes in your sleep times make it hard to re-set your internal clock. In general, using light treatment in the evening should help someone who regularly works nights. You would also want to avoid daylight when you come off work and go home to bed and using dark sunglasses can help, but should be used with caution.
5. Seasonal Affective Disorder (SAD)
The most common condition in which light therapy is used is S.A.D.. Treatment for this is usually between 20 mins and an hour depending on the lightbox. Typical symptoms would include feeling sad, anxiety, social problems not wanting to see people, craving for carbohydrates and lethargy, lacking in energy during the winter. In severe forms it can cause depression, a milder version is often called the ‘Winter Blues.'
Light therapy has been shown to be effective as one of the best non drug treatments for seasonal and non seasonal depression.