DO YOU fall asleep with the TV on or use a night light?
Being exposed to light during the night can up your risk of , scientists say.
The brighter the light, the higher the risk of five cardiovascular diseases, a study from the Flinders and Medical Research Institute suggested.
“Light at night causes circadian disruption, which is a known risk factor for adverse cardiovascular outcomes,”; researchers wrote in medRxiv.
– the body’s 24-hour clock that governs when we feel sleepy or alert as well as other biological functions – play a role in regulating blood pressure, clot formation and heart rate.
Even short-term circadian disruption has been linked to increased risk of , elevated heart rate and and inflammation, study authors wrote.
For instance, studies show that shift workers exposed to light at night have a higher risk of “adverse cardiovascular events, coronary heart disease, heart failure, atrial fibrillation, and mortality”;.
Exposure to light at nighttime can also come from electronic devices like phones, laptops and TV, lights within the home or streetlights outside.
Scientists noted that previous studies into the subject relied on smaller pools of participants and subjective reports on light exposure.
Their study of 88,905 people – which has yet to be peer reviewed – used data captured from wrist-worn light sensors and had a follow-up period of nine and a half years.
It assessed whether exposure to light at night was linked to a higher risk of coronary artery disease, , , , and .
The data was used to create “24-hour light exposure profiles for each participant”;.
Researchers then compared this to records from hospital admissions, primary care, self-reports, and death register reports.
Participants hadn’t been diagnosed with any form of cardiovascular disease at the start of the study.
Study authors found: “Individuals exposed to higher levels of personal night light had higher risks for incident coronary artery disease, heart attack, heart failure, atrial fibrillation, and stroke.
“These findings support night light exposure as an important risk factor for adverse cardiovascular health.
“Exposure to night light predicted higher risk of cardiovascular diseases, with clear dose-dependent relationships for each outcome,”; they added.
This meant that the brighter the light, the higher participants’ risk of disease.
Those exposed to the brightest lights at night had a 23-32 per cent higher risk of coronary artery disease, a 45-56 per cent higher risk of heart attack, and a 28-30 per cent higher risk of stroke.
They also had a 45-56 per cent higher risk of heart failure, and a 28-32 per cent higher risk of atrial fibrillation.
“Higher risks of cardiovascular diseases were observed for men, and older individuals,”; researchers added.
“We observed stronger relationships of night light with risks of heart failure and coronary artery disease in women.”;
Younger participants were also found at an increased risk for heart failure and atrial fibrillation.
The study team suggested that “avoiding light at night may be a useful strategy for reducing risks of cardiovascular diseases”;.
Several other studies have explored the link between sleep and heart disease.
Here are three other habits that could be upping your risk.
1. Not sleeping enough
Getting enoughis important for your heart and circulatory health.
It’s recommended that people get between seven and nine hours of kip a night.
Regularly snoozing five hours a night or less was , where blood vessels in the legs become clogged, in a 2023 study.
2. Irregular routine
A study published in the Journal of Epidemiology and Community Health last year found that people who do not keep to regular sleep schedules – meaning they went to sleep or woke at differing times – had a higher risk of stroke and heart attack.
This was regardless of whether people are getting enough sleep overall.
A recent study also warned thatcan increase the risk of a heart attack or stroke – even for “perfectly healthy”; people.
Lack of shuteye triggers molecular mechanisms linked to a greater risk of, according to the findings.
3. Taking naps
A 2023 study found that napping on a regular basis was linked with, which contributes toand.
People who “usually”; napped had a 12 per cent higher risk of developing high blood pressure, compared to those who never napped.
Their risk of stroke was 24 per cent higher.
