Because blue light exists naturally in abundance from the sun, our biology is primed to interpret blue light as daytime– time to be awake! This mechanism works through, you guessed it, our eyes. The melanopsin receptor in our eyes send a signal to the suprachiasmatic nucleus, which in turn activates or deactivates the pineal gland, which produces melatonin.
Melatonin, the hormone that reduces our alertness and invites sleep. Although melatonin is produced by various tissues in the body the major source is the pineal gland. Melatonin produced by the pineal gland occurs in the absence of light. Although, to some extent, our body will attempt to retain the circadian rhythm, the pineal gland will cease melatonin production after even one second exposure to blue light wavelengths.
Working on your laptop burning the midnight oil? No melatonin. Watching TV while you fall asleep? Limiting melatonin. Checking Facebook one last time in bed? Limiting melatonin.
Sleep is vital to both our physical and mental health. Sleep is involved in nearly every aspect of our body’s programing, from balancing hormones to ensuring that your immune system is working properly. Without quality sleep at the right time, we deprive our body of an essential need– and it all starts with the eyes.
Think about blue light consumption as if you lived in a time before technology. When the sun goes down, it’s time to start blocking all blue light from the devices so that your body can slip into sleep mode and recharge…probably a good time to recharge those devices as well.