Light regulates the day/night and sleep/wake mechanisms of our brain.
- Mood: Light regulates the internal clock in the hypothalamus in the brain, which is responsible for circadian (24-hour) changes, hormonal secretions such as corticoids, neurotransmitters such as melatonin (“sleep hormone”).
- Vigilance: Other areas of the brain involved in our attention and concentration skills are also sensitive to light.
- Sleep: Our biological clock needs light to know when to promote sleep or wakefulness. Morning light is particularly important for resetting it.
Light therapy consists of diffusing bright light for a short period each day, so as to compensate for the lack of light and resynchronise the internal clock. It will promote the secretion of serotonin, dopamine and cortisol and inhibit the release of melatonin.
It is indicated in:
- Seasonal affective disorder
- Major depressive disorder
- Bipolar disorder
- Sleep disorders
- Minor mood and stress disorders as bad days drag on
Light therapy is used:
- in one session per day, in the morning, as soon as possible after waking, preferably between 7am and 9am;
- for 20 to 30 minutes;
- with a recommended output of 10,000 lux;
- at a distance of 30-40 cm from the light therapy device;
- using a light therapy lamp, a Class IIa medical device.