The Light Bulb in Your Nursery Might Be Wrecking Your Sleep

If you're a breastfeeding mom scrolling your phone during a midnight feeding, you're not just keeping yourself awake. According to circadian rhythm expert Heidi Sime, you're destroying the melatonin in your breast milk in real time. "You're giving yourself a shot of cortisol," she says. "Now it's going to go into your milk and you're going to give your baby a shot of cortisol." The blue light from the screen signals daytime to your brain, which triggers a stress hormone cascade that passes directly to the infant. And because the baby's crown is exposed to that same blue light during feeding, you're training their developing circadian rhythm toward wakefulness rather than sleep.

Sime co-founded DreamWalkers with her husband Thaddeus Owen after discovering that most women's health struggles—poor sleep, hormonal imbalances, dull skin, even infertility—trace back to something they never think about: their light environment. She calls it the "fishbowl problem." You can give a fish perfect food and fix its fin, but if the water is polluted, none of it matters. Your home's lighting is the water you're swimming in.

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