Circadian Health Glossary
Action Spectrum
The action spectrum is a graph that delineates the effectiveness of different wavelengths of light in eliciting a specific biological response. In the realms of sleep science and light therapy, it’s particularly focused on how various light wavelengths can suppress the production of melatonin.
Key Wavelengths in the Action Spectrum
The action spectrum for melatonin suppression peaks around 460-480 nanometers, which falls within the blue light. However, there is some sensitivity across the visible light spectrum, though with reduced effectiveness compared to blue light. While blue light is the most potent in suppressing melatonin and thus affecting our sleep patterns, it’s important to note that other wavelengths also play a role, albeit less significantly.
Applications in Light Therapy
Light therapy devices, such as light therapy glasses, are engineered to emit light at wavelengths that effectively suppress melatonin, thereby helping to regulate sleep-wake cycles. These devices are invaluable for treating sleep disorders, including Seasonal Affective Disorder (SAD), and for helping individuals whose natural sleep rhythms are out of sync, such as shift workers or those experiencing jet lag.
How to Leverage the Action Spectrum?
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Mindful Screen Use: Limit screen time in the hours leading up to bedtime or use devices with night mode settings that reduce blue light emission.
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Light Therapy: For those struggling with sleep disorders or wanting to adjust their sleep-wake cycles, consider using light therapy glasses designed with the action spectrum in mind.
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Natural Light Exposure: Make a conscious effort to expose yourself to natural sunlight, especially in the morning, to help regulate your circadian rhythm.