Heart failure affects about 6.7 million people over the age of 20 in the United States, with an incidence of more than one million new diagnoses annually, according to data from the American Heart Association. Meanwhile, in Mexico it is estimated that this condition affects around 750 thousand people, according to data from the Government’s Health Secretariat, which consolidates it as a critical public health challenge due to the increase in the prevalence of hypertension and obesity.

The condition, which occurs when the heart muscle does not pump blood through the body as well as it should, is usually the result of damage caused by conditions such as heart attacks or uncontrolled high blood pressure.

If you’re looking to reduce your risk naturally, the most research-backed recommendations focus on eating a heart-healthy diet, exercising regularly, avoiding smoking and alcohol, and keeping conditions like hypertension under control.

But beyond these obvious measures, scientists are now exploring the impact of another, much less obvious factor: light, especially exposure to bright light while we sleep.

Although turning off the lights has long been associated with deeper, more restful sleep, new evidence suggests that sleeping in complete darkness may also have additional, unexpected benefits for the heart.

What research says about light and the heart

Having a light on at night may be comforting for safety reasons if you’re afraid of the dark, but there may be good reasons to reconsider how you set your lighting when sleeping.

According to research published in JAMA Network Open, people who sleep in brightly lit rooms, such as those with an overhead light on, have up to a 56% higher risk of developing heart failure than those who sleep in total darkness.

In the largest study of its kind to date, researchers followed nearly 89,000 adults ages 40 and older, using light sensors on their wrists to measure the amount of artificial light they were exposed to at night. Additionally, they analyzed his medical records for almost a decade.

The results showed that exposure to brighter light during sleep was associated with a significantly increased risk of several major cardiovascular conditions, even after taking into account age, lifestyle, sleep habits, and other established risk factors.

In addition to a higher risk of heart failure, those who slept in the brightest light also had a 32% higher risk of coronary artery disease and a 28% higher risk of stroke.

Although the researchers were quick to caution that the study does not definitively prove that light causes heart disease, they did note that there is a strong correlation, even when other lifestyle factors were taken into account.

What scientists think is happening

Researchers don’t know for sure why nighttime light might increase heart risk, but they think several biological mechanisms could be involved, based on previous research.

First, exposure to bright light at night interferes with the circadian rhythm, the body’s internal 24-hour clock that influences sleep, hormonal regulation, blood pressure, and metabolism. When this biological clock is disrupted due to changes in usual light levels, it can put pressure on the cardiovascular system.

Similarly, darkness also triggers the release of melatonin, the sleep hormone that helps you relax before sleeping, but also regulates blood pressure and reduces inflammation, key factors in the risk of cardiovascular diseases.

In addition, the authors of the study point out that previous laboratory research has shown a relationship between an increase in nighttime heart rate and exposure to intense lights, which prevent blood pressure from falling naturally at night.

However, other experts point out that the research should be analyzed from a broader perspective, since light exposure hardly acts alone.

Emily McGrath, senior cardiac nurse at the British Heart Foundation, explains: “Previous research has found that exposure to light at night can affect the body’s glucose metabolism, and that this is associated with an increased risk of obesity and heart disease.”

“But people who are exposed to more light at night also tend to sleep less, and Lack of sleep can also increase the risk of cardiovascular disease.”he adds. “When sleep duration is taken into account, the relationship between nighttime light exposure and cardiovascular risk is reduced, as was observed in this study.”

Finally, he warns: “We need more research to better understand the impact of artificial light on our body and separate its effects from other nighttime factors, such as shift work.”

Tips to make sleep healthier for your heart

Although the wearable devices used in the study measured personal exposure to light at night, the researchers did not analyze where that light came from: whether from table lamps and hallway lights, screens and night lights, or from outside light pollution, such as streetlights filtering into bedrooms.

This means that it is difficult to quantify whether sleeping with a light on poses the same risk as being exposed to constant outdoor light pollution, such as living on a busy, well-lit street.

Still, if you want to make your rest a little less stressful on the heart, small changes could help. Here are some steps you might consider:

Sleep in the dark

Before going to bed, turn off lamps, televisions, and overhead lights, and consider using blackout curtains if light is coming in from outside.

Set a “cut off time” for your devices

Phones and tablets emit a particular type of blue light that is thought to inhibit the release of melatonin. To avoid confusing your biological clock, try to turn them off at least an hour before bed.

Maintain a regular sleep routine

In addition to dimming the lights, going to bed and waking up at around the same time every day helps keep your body clock in sync.

Avoid spicy foods and alcohol

Regarding diet, spicy foods, alcohol and large meals can take a long time to digest, so it is best to avoid them in the hours before going to sleep. Opt for lighter snacks and herbal teas that promote sleep.

Article written in english originally by Liz Connor.

“This story was translated from English with the help of a generative artificial intelligence tool and edited and reviewed by an editor from the Yahoo en Español newsroom.”