Key and Common Cause Behind Rapidly Spreading Heart Disease Discovered

Islamabad (Qudrat Daily) — For the past few years, medical experts have been assessing what effects the lights used to illuminate homes and other places at night have on people’s health.

For example, a study in November 2022 found that spending more time in artificial outdoor lights increases the risk of developing diabetes.

A study in March 2023 stated that using any kind of light while sleeping at night increases the risk of diseases such as diabetes, obesity, and high blood pressure in old age.

Now a new study has found that not sleeping in complete darkness at night increases the risk of being affected by heart disease.

Research from Tulane University in the United States stated that sleeping with light at night has negative effects on the structure and function of the heart.

The study analyzed data from more than 11,000 people obtained from the UK Biobank.

These individuals were made to wear a light sensor on their wrist for 7 days, which helped researchers know how much light they slept with at night.

After 3 years, MRI scans of these individuals’ hearts were conducted.

These detailed images helped researchers examine the structure of the heart and learn about its functions.

Afterward, researchers compared the heart health of people who slept in complete darkness and those who slept in dim light.

The results showed that the wall of the left chamber of the heart becomes thicker in people who sleep with light at night, while the internal capacity shrinks.

The scans also revealed that the elasticity of the heart muscle decreased, and a decrease in elasticity indicates that the heart’s functions have become less effective.

Such changes were also seen in the right chamber of the heart.

Researchers said this is the first study of its kind, and the results prove that sleeping with light at night causes changes in the structure of the heart.

They further said that such changes usually occur when the heart faces chronic stress or injury, which weakens the heart and increases the risk of heart failure, heart attack, or stroke.

The results of this study were published in the European Heart Journal.

Earlier, in October 2025, a study in the journal JAMA Network Open stated that people who sleep in brightly lit rooms have up to a 56 percent increased risk of heart failure.

Similarly, the risk of coronary artery disease increases by 32 percent and the risk of stroke by up to 28 percent.

The study examined data from more than 500,000 people aged 49 to 69.

These individuals were made to wear light trackers for a week between 2013 and 2022, and the effects of being in light from 12:30 AM to 6 AM were analyzed.

Overall, these individuals’ health was assessed for 9 years.

The study found that people accustomed to sleeping in more light have up to a 47 percent increased risk of heart attack and up to a 32 percent increased risk of heart rhythm disorder.

The risk of heart failure is higher in women compared to men, while sleeping in more light also increases the risk of heart failure and heart rhythm disorder in young people.

However, researchers acknowledged that the study is limited.

They said the study only indicated an association but could not prove why being in light at night leads to heart disease.

They said that if it is not possible to make the room completely dark at night, try to use dim light.