As soon as the sun sets, we turn on the lights inside the house, from overhead to lamp lights. Also, the bright light coming from the street illuminates the houses. From televisions to phones, screens include these lights. True darkness, indeed, at night, is rare these days. This comes at its own health cost. Either light coming from the streets due to rampant urban light pollution, or our own screens and overhead lights.
Also read: Take the stairs instead of the elevator: Study shows just 3 minutes of movement daily can reduce risk of heart attack and stroke
A study published in JAMA Network on October 23, 2025 found that exposure to bright light at night can take a toll on your heart health.
What did the study find?
This habit of lighting the house brightly at night affects not only the circadian rhythm but also heart health. Study findings show that when the body’s internal clock is disrupted, heart health is also affected. The circadian rhythm is responsible for sleep, hormone regulation and many other functions.
What bright light does is that it disrupts the body’s internal clock. According to researchers, this disturbance triggers a series of effects. This physical reaction to bright light at night causes physical confusion, which leads to high blood pressure, swelling, and increased heart rate. Prolonged physical suffering like this paves the way for heart problems.
People who often work night shifts are affected, as they experience bright light when they should be sleeping. But similarly, its effect is also visible on those people who check their phones in bed.
According to the findings, people who were most exposed to the brightest night light had a 32 percent higher risk of coronary artery disease, a 56 percent higher risk of heart attack, and a 30 percent higher risk of stroke. The physical stress from night light is so severe that these risks persist even after taking into account other factors such as exercise, diet, genetics, and sleep habits.
What does it mean?
If you have a habit of sleeping with the lights on or checking your phone in bed, it’s time to reconsider. Studies have shown a direct link between night light exposure and heart disease. Instead, turning off the lights helps protect your heart. Researchers recommend dimming indoor lights after sunset, using thick curtains, and avoiding screens before bed.
Note to readers: This article is for informational purposes only and is not a substitute for professional medical advice. Always seek the advice of your doctor with any questions you may have about a medical condition.
