TL;DR: New research suggests that exposure to light while you sleep may be associated with changes in heart structure and a higher risk of cardiovascular disease. While the study doesn’t prove that nighttime light causes heart problems, creating a darker bedroom is a simple step that may support better sleep and heart health.
Streetlights shining through the window. A TV left on. The glow from your phone or even those tiny lights on chargers and electronics.
Most of us have at least a little light in our bedrooms at night. But new research suggests that nighttime light exposure may be associated with changes in the heart, giving us another reason to think about how dark our bedrooms really are.
A study published in the European Heart Journal found a clear link between nighttime light exposure and structural changes in the heart, the kind of changes that show up before cardiovascular disease does. Below, we'll break down what the researchers found, why it matters, and what you can actually do about it tonight.

