Getting bright light in your eyes right after waking up tells your body when to wake up and start burning energy, which helps your whole metabolism work right.
Evidence from Studies
Supporting (2)
Community contributions welcome
In animals, getting bright morning light helped their body clocks work better and improved how their body used energy — just like the assertion says morning light should help humans too.
This study showed that when people are exposed to bright or blue light right after waking up, their stress hormone (cortisol) goes up — which is exactly what the assertion says morning light should do to help set the body’s internal clock and improve metabolism.
Contradicting (2)
Community contributions welcome
Even if teens got bright light in the morning, staying up late with room light erased all the benefits — meaning morning light alone isn’t enough to set the body clock, which contradicts the claim that it’s the main cue.
Even very dim light can reset your body clock — so you don’t need bright morning light like the assertion says; weaker light works too, which weakens the claim.