Sleeping with a light on could harm your heart. Researchers put sensors on people to measure the light in their bedrooms. Later, people with no heart disease had an MRI scan. The scans showed a link between sleeping with a light on and changes in the heart. For some people, the heart was less able to pump blood.

Light could be a new risk for heart disease. A researcher suggested that turning off lights while sleeping could help prevent heart problems. People should turn off lights in their bedroom. Their room should be as dark as possible. The researcher said using blackout curtains and turning off tiny LED lights were good ideas.