Light Therapy

Light therapy is the timed exposure to full spectrum or low blue light spectrum artificial light to help stimulate, suppress or reset the circadian sleep/wake cycle.

Light therapy may also comprise minimising the exposure to the low blue light spectrum to stimulate, advance or delay melatonin production. Melatonin is important and helps regulate the internal body clock’s cycle of sleep and wakefulness. Other claims are made for it: it has anti-oxidant and free radical scavenging properties and some say it has anticancer and anti-ageing effects, but there is no proof of this to date.

What Does Light Therapy Do?

Light Therapy (Increasing, decreasing or timing exposure to light) can have significant effects on the timing, quality and duration of sleep and suppress physical symptoms of depressive illness most notably, Seasonal Affective Disorder, SAD. (1) 

Insomnia (sleeplessness) can be caused by exposure to artificial lighting, including television and computer screens, around the work place or home. The blue light contained in the light spectrum can cause the delay or suppression of melatonin. Modern lifestyles and living with electronic light sources make it difficult to minimise exposure to artificial light late in the evening.

  By blocking the low blue light spectrum with the use of special filtering glasses for example, melatonin has a chance to become more regulated and evening tiredness can return to normal advancing DSPS so the individual can sleep at normal times. 

Outdoor natural light is best to help with seasonal depression, but such light may not be easy to get in winter months. Artificial light can be used as an alternative. People experiencing SAD, a depressive illness with a seasonal component and often called the “winter blues”, develop depressive like symptoms.

Symptoms begin in autumn or winter, and lessen or cease during spring and summer. SAD shares some symptoms with major depressive disorder (MDD), including depressed mood, a lack of energy, difficulty concentrating and fatigue. Increase in appetite, weight gain, carbohydrate craving, and excessive daytime sleepiness can also be experienced. (2)

Consultation with a Sleep Specialist will help achieve the best outcomes of treatment. You may need a referral from your family Physician.


  1. Terman M: Task force report on light treatment for sleep disorders. J Biol Rhythms 1995; 10: 101-176. Editor
  2. Magnusson A, Boivin D. Seasonal affective disorder: an overview. Chronobiol Int 2003; 20: 189-207.