Blue light emitted by devices like smartphones, computers, and televisions is becoming a major factor disrupting our sleep cycles. Research reveals that a significant number of Americans use electronic devices close to bedtime, contributing to poor sleep quality. Reducing exposure to blue light, particularly in the evening, is a simple yet effective way to help your body prepare for restful sleep.

What Is Blue Light?

How Does Blue Light Impact Circadian Rhythms?

Circadian rhythms are 24-hour cycles that control essential bodily functions, including sleep. Light is the primary factor that aligns these rhythms with day and night. Historically, exposure to sunlight during the day helped set our body clocks, signaling when to be awake and when to sleep. However, the widespread use of artificial lighting and electronic devices has introduced more light exposure after dark, disrupting these natural cycles.

Blue light, in particular, has the strongest impact on circadian rhythms. During daylight hours, blue light helps us feel alert by stimulating the brain, raising body temperature, and increasing heart rate. But in the evening, exposure to blue light can confuse the body’s internal clock, suppressing melatonin—the hormone responsible for making us feel sleepy. As a result, our brains may remain in “daytime mode,” preventing us from winding down for the night.

Health Consequences Of Disrupted Sleep

Persistent disruption of circadian rhythms can lead to a range of health issues, including metabolic disorders, poor mental health, and increased risk for conditions like depression and anxiety. Furthermore, the inability to sleep well at night affects cognitive performance, mood, and overall well-being. Chronic exposure to blue light in the evening may significantly contribute to these negative health outcomes.

Devices That Emit Blue Light

Many common devices in our daily lives emit blue light, including:

- Smartphones and tablets

- Computer monitors and laptops

- Televisions and e-readers

- LED and fluorescent lighting

- Video game consoles

How To Minimize Blue Light Exposure

To reduce the effects of blue light on your sleep, here are some practical strategies:

1. Turn off screens before bed: Try to avoid using electronic devices at least two to three hours before bedtime. Reducing screen time helps prevent blue light from interfering with melatonin production.

2. Adjust your lighting: Dim your home’s lights or switch to warmer-toned lighting in the evening. You can also use lamps with red or orange light, which are less likely to impact your circadian rhythms.

3. Night mode settings: Many smartphones and computers have a "night mode" feature that reduces blue light emission. Make use of these features to limit exposure in the hours leading up to bedtime.

4. Blue light-blocking glasses: Special glasses designed to filter out blue light may be helpful for some individuals. These glasses can block or reduce the melatonin-suppressing effects of blue light.

5. Apps for blue light reduction: There are several smartphone and computer apps available that reduce blue light emission, allowing you to use your devices before bed without disturbing your sleep.

6. Create a sleep-friendly environment: If you can’t control light sources in your bedroom, consider using an eye mask to block out ambient light and promote better sleep.

Even a mild case of COVID-19 may trigger long-lasting eye problems, with new research revealing that persistent inflammation and nerve damage could be responsible for symptoms that standard eye tests often fail to detect.

The study, led by researchers at Linköping University in Sweden and published in Nature Communications, sheds light on why some COVID-19 survivors continue to experience debilitating vision issues months or even years after infection.

The research began after people who had recovered from mild COVID-19 sought medical help for persistent eye complaints. Many reported:

• Severe eye pain
• Light sensitivity (photophobia)
• Difficulty reading and focusing
• Extreme eye fatigue

Many participants said the condition significantly disrupted their daily lives, preventing them from working or continuing their education.

What the Study Found

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Researchers evaluated 100 people who developed eye problems after mild COVID-19 but had never been hospitalized. Their symptoms had persisted anywhere from three months to three years.

The findings were compared with those of 32 people who had recovered from mild COVID-19 without developing eye symptoms.

Using advanced imaging and laboratory techniques, researchers identified several abnormalities that conventional eye exams failed to detect.

Persistent Inflammation and Nerve Damage

The study found evidence of:

• Long-term inflammation in the eyes
• Damage to nerves controlling multiple eye functions
• Abnormal immune activity involving T cells
• Changes in proteins found in tear fluid

Lead author Petros Moustardas, senior research associate at Linköping University, said the findings indicate that COVID-19 may trigger a severe immune reaction in the eyes, resulting in chronic inflammation and nerve dysfunction.

Why Light Sensitivity Happens

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One of the most common complaints among participants was extreme sensitivity to light. Researchers found that their pupils were allowing too much light into the eyes because of impaired nerve control.

This abnormal pupil function was also associated with:

• Headaches
• Difficulty reading
• Trouble maintaining focus

An Unusual Eye Movement Disorder

The study also identified impaired coordination between the two eyes.

Some participants developed adult-onset strabismus—commonly known as crossed eyes—a condition that is rare in adults.

Researchers believe this occurred because COVID-19 affected the nerves responsible for controlling eye muscles.

A New Way to Diagnose COVID-Related Eye Problems

Because routine eye tests often miss these abnormalities, the research team developed two diagnostic models.

The first relies on specialized ophthalmic tests available at advanced eye clinics, while the second combines these examinations with tear fluid protein analysis to improve diagnostic accuracy.

Researchers hope these models will help doctors recognize COVID-related eye syndrome earlier and pave the way for future treatments.

"We found that the problems experienced by those affected were not detectable by standard tests. We had to perform specialised examinations to detect deviations. The puzzle pieces then fell into place, and we found explanations for the symptoms," said Neil Lagali, professor of experimental ophthalmology at Linköping University.

He added that while the findings provide important clues about how COVID-19 affects the eyes, more research is needed to develop effective treatments for those living with persistent vision problems.

Yawning has a certain fact attached to it, which is without a doubt a reason for curiosity and amazement among people. Many of you must have noticed that when someone nearby yawns, you often end up yawning too. Even in some cases, a person yawns just after hearing the word yawn or watching someone yawn on screen.

Yawning itself is a natural physical process that involves taking a deep breath and stretching the muscles used for breathing. Some experts suggest that it may help increase alertness and leave us feeling refreshed. However, while scientists have proposed several theories about the purpose of yawning, one question continues to intrigue researchers: why are yawns so contagious?

Dr. Debanjan Pan, Consultant Psychiatrist at Saltlake Mindset, told Health and Me, "Contagious yawning may be linked to mirror neurons, which help us understand and imitate the behavior of others. Humans have survived by living in groups, and our brains are naturally wired to synchronize with the people around us. When we see someone yawn, the same neural networks in our brains may become activated, prompting us to yawn as well."

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Yawning involves taking a very deep breath, which increases oxygen intake and stimulates several parts of the respiratory system. This deep inhalation can temporarily raise the heart rate and boost blood circulation to the spinal cord and the brain, making a person feel calmer and more relaxed afterward.

According to Dr. Pan, this sense of relaxation may also explain why yawning is contagious. When we see someone else yawn, the brain's empathy circuits, particularly those linked to mirror neurons, become active. As humans are highly social beings, we often unconsciously mimic the behaviour and emotions of people around us, causing a yawn to spread from one person to another.

But there might be a question: if yawning is contagious because humans are social animals and human brains are naturally wired to synchronize with the people around them, then why doesn't coughing and sneezing have the same effect?

Dr. Vikas Mittal, Director - Pulmonologist, CK Birla Hospital, Delhi, addressed this very issue and explained, "Yawning is different than coughing and sneezing. Coughing and sneezing are protective reflexes that protect you from irritants. They can be contagious, but that contagion comes after one or two days, not immediately as is with yawning. Yawning occurs because of the brain's automatic self-mirroring networks."

Dr. Mittal further added, "What it means is when somebody yawns, then your brain starts imitating that unintentionally. Not only yawning, but other emotions like a smile, laugh, and fear can trigger the same emotion in the people around you. This is because of the same brain's automatic self-mirroring networks."

Contagious yawning appears to be more than a simple reflex, offering insights into empathy, social bonding, and the human brain.

Cardiovascular-kidney-metabolic (CKM) syndrome is emerging as a major public health threat, according to new guidelines from the American Heart Association (AHA), which identify obesity as a key driver of the condition's development and progression.

The guidelines, jointly issued by the AHA and the American College of Cardiology (ACC), reframe excess weight as more than a number on the scale, describing it as a significant health risk closely linked to diabetes, chronic kidney disease and cardiovascular disease.

According to the AHA, nearly 9 in 10 adults in the United States have at least one condition associated with CKM syndrome. These include high blood pressure, abnormal cholesterol and other lipid disorders, high blood sugar, reduced kidney function and excess body weight.

With obesity rates continuing to rise, the guideline urges healthcare professionals to have prevention-focused conversations with patients about maintaining a healthy weight to reduce the risk of future heart, kidney and metabolic diseases.

“CKM syndrome is a real, rising public health threat,” said Chiadi E. Ndumele, an American Heart Association volunteer and chair of the writing committee for the new guideline.

“In terms of CKM health, weight is not just about a number on a scale — people with the same body weight can have very different health profiles. Rather, what’s most important is how fat tissue affects your metabolic health. This includes how your body manages blood sugar levels and how fat is used and stored,” Ndumele, who is also director of obesity and cardiometabolic research at Johns Hopkins University in Baltimore.

The New CKM Syndrome Guideline

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The updated guideline replaces the 2013 recommendations for managing overweight and obesity. CKM syndrome itself was first formally defined by the American Heart Association in 2023.

The guideline highlights several strategies to improve the prevention and treatment of CKM syndrome:

• Use the Predicting Risk of Cardiovascular Disease EVENTs (PREVENT) equations to estimate 10-year and 30-year cardiovascular disease risk. Unlike previous tools, PREVENT incorporates kidney and metabolic health factors for a more comprehensive risk assessment.
• Screen patients for social determinants of health, including food insecurity, housing instability and financial strain, which can increase the risk of CKM syndrome.
• Promote coordinated, multidisciplinary care focused on healthy lifestyle behaviors, including physical activity, nutrition, weight management, blood pressure control, blood sugar management and cholesterol reduction.
• Alongside lifestyle interventions, use medications and surgical therapies when appropriate to manage blood pressure, cholesterol, blood sugar and obesity while protecting heart and kidney health.
• For the first time, the guideline recommends GLP-1-based therapies for select individuals with obesity and/or Type 2 diabetes who are at elevated cardiovascular risk. Metabolic and bariatric surgery is also recognised as an effective treatment option for eligible patients.

How Can CKM Syndrome Be Prevented?

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The guideline emphasizes that early lifestyle changes can significantly reduce the risk of heart attack, heart failure, stroke and kidney failure.

People are encouraged to follow the AHA's Life's Essential 8, which promotes

• regular physical activity,
• a heart-healthy diet,
• maintaining a healthy weight,
• controlling blood pressure,
• maintaining blood sugar
• better cholesterol control,
• avoiding tobacco,
• getting sufficient quality sleep.