The hidden risk to your heart from sleeping in low light

Key Points:

• A new study published in the European Heart Journal found that even low levels of light exposure during sleep (above 3 lux) can thicken heart muscle walls and reduce heart function, increasing the risk of future heart disease.
• The study analyzed over 11,000 participants from the UK Biobank, measuring nighttime light exposure via wrist sensors and assessing heart health through MRI scans three years later, revealing that brighter bedrooms correlated with adverse cardiac remodeling.
• Approximately 24% to 49% of the heart damage was linked to shorter sleep duration caused by nighttime light exposure, while other factors like stress and biological changes may account for the remaining risk.
• Experts recommend minimizing bedroom light to below 1 lux using blackout curtains, turning off hallway lights, using dim red or amber bedside bulbs, and employing sleep masks if necessary to protect heart health and improve sleep quality.
• Some limitations of the study include the short one-week light measurement period and the use of wrist sensors as a proxy for eye exposure, indicating the need for further research to establish causality.