This common sleep habit could be changing the shape of your heart—for the worse

Many people sleep with a night-light their whole lives—though as they grow older, small plug-in light fixtures may be replaced by the glow of laptops or phone screens. While sleeping in a low level of light may be commonplace, doing so comes with its own health hazards, including altering the shape of the human heart.A new study, published this week in the European Heart Journal, links exposure to light while sleeping to cardiac remodeling, or changes to the shape and function of the heart. Specifically, light exposure during sleep led to thickening of the wall of the left ventricle, one of the organ’s four chambers, reducing the space inside the heart. That weakens its ability to flex during a heartbeat, setting the stage for cardiac dysfunction. “Light pollution has emerged as a new risk factor for cardiovascular disease,” Dr. Lu Qi, a professor at Tulane University and an author of the study, said in a press release. “Our findings, together with evidence from other studies, suggest that reduction of nighttime light exposure should be considered as one of the potential strategies for preventing heart disease by clinicians and policymakers.” How much light is too much light? To d…