As the sun goes down, we switch on the lights indoors, from overhead to lamp lights. At the same time, bright lights from the street illuminate homes. Screens add to these lights, from television to phones. True darkness, in fact, at night, these days is rare. This comes at its own health cost. Either the lights are pouring in from the streets because of the rampant urban light pollution, or our own screens and overhead lights.
A study published in the JAMA Network on October 23, 2025, found that bright light exposure at night may weigh heavily on your heart health.
What did the study find?
This habit of brightly illuminating the home at night not only affects circadian rhythm but also heart health. The study's findings show that when the body's internal clock is disrupted, heart health is also affected. Circadian rhythm is responsible for sleep, hormone regulation and many other functions.
What bright light does is it throws the body's internal clock off the rhythm. As per the researchers, this disturbance triggers a series of effects. This physical response to bright light at night triggers physiological confusion, which leads to high blood pressure, inflammation, faster heart rate. Prolonged physical distress like this paves the way to heart problems.
People who often work night shifts are affected, as they experience exposure to bright lights when they should be sleeping. But similarly, the effect shows up in those who check phones in bed, too.
As per the findings, those who were exposed to the brightest night light faced a risk of 32 per cent higher coronary artery disease, 56 per cent higher heart attack risk and 30 per cent higher stroke risk. The physical stress from night lights is so severe that these risks stayed despite taking other factors such as exercise, diet, genetics and sleep habits into consideration.
What does it mean?
If you are in the habit of sleeping with lights on, or even checking your phone in bed, it's time to reconsider. The study showed a direct connection between night light exposure and cardiovascular disease. Instead, turning down lights helps protect your heart. The researchers recommended dimming indoor lights post sunset, using thick curtains and refraining from being on screen before bedtime.
Courtesy: Hindustan Times
Bd-pratidin English/ ANI
