Does Artificial Light at Night Carry Heart Disease Risk?
Jake Newby
| 3 min read
Jake Newby is a brand journalist for Blue Cross Blue...
Key Takeaways
- Artificial light at night may disrupt circadian rhythms, potentially increasing the risk of heart disease, stroke, atrial fibrillation and heart failure.
- Limiting nighttime exposure to phones, televisions and bright lights may support better sleep and long-term cardiovascular health, according to research.
- Artificial light can suppress melatonin production, contributing to poor sleep, metabolic problems, anxiety, depression and other chronic health concerns over time.
- Healthy habits like regular exercise, balanced nutrition, quality sleep and preventive care remain the foundation of protecting long-term heart health.
The glow from your smartphone, tablet or bedside lamp may seem harmless, but emerging research suggests too much artificial light at night could affect more than just your sleep quality.
Recent studies indicate that exposure to light during normal sleeping hours may increase the risk of several forms of cardiovascular disease (CVD) by disrupting the body's internal clock, also known as the circadian rhythm.
While more research is needed to deem artificial light as a serious threat to heart health, scientists say the evidence is strong enough to consider nighttime light exposure.
Is blue light at night bad for your heart?
A 2025 JAMA Network Open study followed nearly 89,000 adults age 40 and older and had them wear wrist sensors to track how much artificial light they were exposed to while sleeping.
Compared to those who slept in darker environments, researchers found that people exposed to the brightest levels of light at night had significantly higher risks of developing:
- Coronary artery disease
- Heart attack
- Heart failure
- Atrial fibrillation
- Stroke
The associations between artificial light and heart disease risk remained even after accounting for factors like physical activity, smoking, diet, sleep duration, and genetic risk in the subjects.
Researchers also found that nighttime light exposure may interfere with circadian rhythms that help regulate blood pressure, metabolism, blood vessel function, and inflammation. When those rhythms become disrupted, cardiovascular health may worsen over time.
Another 2025 study, published in the Journal of the American Heart Association (JAHA), reached a similar conclusion. Researchers reported that higher exposure to artificial light at night was associated with biological changes linked to CVD, including more stress activity in the brain and increased inflammation in blood vessels.
Findings from both studies suggest that artificial light – such as the blue light from televisions and smart devices – at night carries some degree of heart disease risk, particularly when exposure is frequent or prolonged.
What are other risks of too much artificial light exposure at night?
Heart health may be the latest artificial light-related issue scientists have flagged, but it’s not the first.
Health experts have long known that exposure to light in the evening can suppress the production of melatonin, a hormone that helps regulate sleep. Poor sleep quality and circadian disruption have been linked to health issues such as:
- Obesity
- Type 2 diabetes
- Impaired immune function
- Anxiety and depression
Reducing screen time before bed remains a common recommendation for improving sleep and one of the pillars of good sleep hygiene.
Simple habits that support heart health
Artificial light at night is unlikely to be the sole cause of heart disease. However, growing evidence suggests that darkness may be more important to cardiovascular health than many people realize. If your nightly routine includes scrolling on a bright phone screen or falling asleep with the TV on, your heart may benefit from cutting back on those habits.
You can also dim lights in the evening to reduce your overall light exposure before bedtime and use blackout curtains in your bedroom to keep it as dark as possible.
Additionally, protecting your heart still comes down to the fundamentals. This includes:
- Maintaining a healthy diet
- Staying physically active
- Getting at least seven to eight hours of sleep per night
- Avoiding tobacco
- Limiting alcohol
- Managing stress
- Keeping blood pressure, cholesterol and blood sugar levels under control
A great way to get ahead of issues like these is to stay on top of yearly preventive care visits covered by your health insurance plan. Click here for a list of preventive services from an in-network provider that do not require a copayment or coinsurance, regardless of whether you’ve met your yearly deductible.
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