Does blue light stop you and your dog sleeping?

Does blue light stop you and your dog sleeping? 
If you have an iPhone, you might already think so. 

Apple’s Night Shift setting reduces blue light in the evening. 
It’s available on iPhones, iPads, and Macs. 
A clever idea. Problem solved, right? 

Not quite. Recent research suggests there’s more to the story. 
Blue light does affect sleep, but it’s not the only culprit. 
Scientists at the University of Manchester explored this mystery further. 
Dr. Tim Brown’s team uncovered a surprising twist. 

Blue light regulates your circadian rhythm — your internal body clock. 
Sunlight is rich in blue light and tells your brain it’s daytime. 
This boosts alertness and keeps you awake. 
But at night, blue light from screens disrupts this natural rhythm. 
It tricks your brain into thinking it’s still daytime. 

Melatonin, the hormone that prepares you for sleep, is affected. 
Blue light suppresses melatonin, delaying the urge to sleep. 
Even short exposure can shift your sleep schedule. 

Is blue light always the villain? 
The Manchester study challenges this idea. 
Under bright light, blue light delays sleep and keeps you alert. 
But under dim conditions, blue light may work differently. 
Dr. Brown’s team found it could be less disruptive than yellow light. 
Soft, dim light — regardless of color — signals your body to relax. 

This is a revelation. It’s not just the color of light that matters. 
The intensity and timing of light exposure are equally important.