What Is Blue Light? How Does It Impact Sleep?

Updated Dec 14, 2024 | 10:45 PM IST

SummaryScreens of electronic devices such as smartphones, computers, tablets, and televisions emit blue light. But does it impact your natural sleep cycle and circadian rhythm?
Blue Light

Blue Light (Credit: Canva)

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?

Blue light is part of the visible light spectrum and is emitted by natural and artificial sources like the sun, fluorescent lights, LED lights, and digital screens. This wavelength is known for influencing our alertness, mood, and sleep patterns. During the day, blue light plays a role in regulating circadian rhythms, helping us stay alert and focused. However, exposure to it in the evening can have a detrimental effect on sleep quality.

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.

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When Your Nervous System Is Overloaded: Signs Your Body Needs A Pause

Updated Oct 7, 2026 | 01:00 PM IST

SummaryNervous system overload can trigger physical, emotional and cognitive symptoms, from fatigue and irritability to poor concentration and sleep changes, signalling that the body needs rest and recovery.
When Your Nervous System Is Overloaded: Signs Your Body Needs A Pause

Credit: AI

In my 13 years of working with clients as a trauma-informed consulting psychologist, I have often noticed that people recognise nervous-system overload only after their body forces them to slow down.

Until then, they may describe themselves as “too sensitive”, “lazy” or “unable to cope”. In reality, these reactions are often the nervous system’s attempt to protect us.

Fight, Flight, Freeze Or Shutdown

Our nervous system continually assesses whether we are safe. When stress feels persistent or overwhelming, the body may move into fight or flight.

We might become irritable, restless, anxious or unusually controlling. The heart may race, muscles tighten and sleep become disturbed. At other times, the system may shift towards freeze or shutdown, showing up as exhaustion, emotional numbness, procrastination, forgetfulness or a strong desire to withdraw.

Also read: LSD-Based Treatment Clears Second Phase 3 Trial: Could It Be The First New GAD Drug In 2 Decades?

When Everyday Reactions May Signal Overload

For example, someone who becomes disproportionately angry over a minor delay may not simply have an “anger problem”; their system may already be carrying days or months of accumulated stress. Another person may sit before a simple email for hours, unable to respond.

What looks like avoidance may actually be a freeze response. Some people remain highly productive while feeling disconnected from their bodies, until headaches, digestive difficulties or fatigue begin demanding attention.

These signs do not automatically indicate trauma or a mental health condition. They are invitations to become curious: What has my system been carrying? When did I last feel rested, supported or genuinely safe?

Small Ways To Help The Body Feel Safer

If you notice these patterns, begin gently. Reduce unnecessary stimulation, eat regularly, protect your sleep and spend time with people around whom you do not have to perform. Slow breathing—particularly allowing the exhale to be longer—may help signal safety. You can also look around the room, notice your feet on the floor and name what you can see and hear. Small, repeated experiences of safety are often more helpful than forcing yourself to “calm down”.

If symptoms persist, interfere with daily life or feel difficult to manage alone, speaking with a trauma-informed therapist can help you understand the patterns beneath them. Therapy is not only for moments of crisis; it can offer a safe space to listen to what the nervous system has been communicating all along.

The body is rarely working against us. Often, it is asking for care in the only language it knows.

By Ms Arouba Kabir, Psychologist & Therapist, Founder - Enso Wellness

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Why Someone Days Away From Death May Start To See Loved Ones: End-Of-Life Doctor & Neurologist Explain

Updated Oct 7, 2026 | 12:00 AM IST

SummarySomeone who is dying may have visions and hallucinations as they move towards the end. Even though there isn't a definitive scientific cause,
Why Someone Days Away From Death May Start To See Loved Ones: End-Of-Life Doctor & Neurologist Explain

Credit: AI

Someone who is dying may start to their loved ones who passed away years ago. This could be unsettling and confusing for families and relatives who may assume that the person is just hallucinating or undergoing a deeper neurological issue.

But hospice physician Dr Christopher Kerr says such experiences are a known phenomenon called end-of-life dreams and visions (ELDVs). Kerr, chief medical officer of Hospice Buffalo, has spent decades studying these experiences in dying patients extensively.

Appearing on The Oprah Podcast, he told Oprah Winfrey that many patients near death describe seeing deceased relatives or people who cared for them during their lives. The experiences can feel completely real to them.

Why Do People Near Death See Deceased Loved Ones?

Also read: Ebola Bundibugyo Virus: Kenya Confirms First Death In Case Imported From Congo

One of the possibilities is that the brain experiences significant changes as the body starts to shut down.

Alterations in sleep, consciousness, metabolism, oxygen levels, medications, and brain chemistry can all affect perception during the final stages of life.

Dr. Rakesh Lalla, Additional Director - Neurology, Fortis Hospital, Mumbai, told HealthandMe, " These visions could be explained by the alterations that occur within the brain as the body starts to close down. Due to oxygen deprivation and altered brain activity, the brain would process memories, feelings, and stimuli differently. The areas responsible for memory processing and vision could become stimulated or disrupted, which could result in some vivid visions or experiences."

The expert also said that these visions do not mean that the person has a neurological or psychiatric issue.

Dr. Lalla said, "They do not necessarily mean that the person is confused or suffering from a psychiatric condition. In many cases, they are brief, peaceful, and emotionally meaningful to the individual. We still do not fully understand why particular people or memories appear."

The neurologist also advised families to stay supportive and calm during such situations.

He added, "The brain’s complex relationship between memory, emotion and perception is likely to play an important role. For families, the key is to remain calm, listen without dismissing the experience, and provide reassurance and comfort."

Also read: Global Life Expectancy Returns To Pre-Pandemic Levels, But NCDs Resulted In 8 Out 10 Deaths: WHO

Hallucinations Or Part Of The Dying Process?

Experts who have been studying ELDVs have also found that these experiences have some distinctive patterns that do not resemble random hallucinations.

In a 2014 longitudinal study led by Kerr, most of the 59 hospice patients who completed the study reported at least one dream or vision. Almost half occurred during sleep, and nearly all patients said the experiences felt real. The most common involved deceased friends or relatives or other loved ones. In fact, comforting visions of deceased people became more common as patients moved closer to death.

A 2026 systematic review of 13 studies similarly found that ELDVs occurred in at least one in five dying adults.

The National Institute on Aging also states that dying people may appear to see or talk to someone who is not present and may report dreams involving deceased relatives or friends. Such experiences are often comforting, and caregivers are generally advised not to immediately correct or challenge the person.

Seeing Loved Ones Could Be A Comforting End

Kerr said that patients seeing deceased loved ones in their visions appeared calmer afterward. His research suggests that these experiences may carry deep emotional meaning for patients.

“Very little is said between the person in the dream and the dreamer, but everything seems to be understood,” Kerr told Oprah.

Scientists still cannot say exactly what produces these experiences or whether they represent anything beyond changes occurring in the dying brain.

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When Do You Need A Heart Check-up?

Updated Oct 5, 2026 | 09:00 PM IST

SummaryA heart health evaluation should ideally take place when the person is feeling completely well, long before any warning signs appear. Starting check-ups at age 30 is important because certain congenital and structural heart conditions remain completely silent for years.
When Do You Need A Heart Check-up?

Credit: iStock

India accounts for one-fifth of global deaths due to cardiovascular diseases (CVDs) or complications related to the heart and blood vessels. Moreover, women are more vulnerable to these complications. Recent data show that women (14%) have a higher prevalence of CVD than men (12%), making preventive care very important for all.

When Should A Heart Check-up Be Done?

The human heart works constantly and efficiently and can compensate for metabolic stress and narrowing of blood vessels without showing any obvious symptoms. Hence, a heart health evaluation should ideally take place when the person is feeling completely well, long before any warning signs appear.

While acute symptoms, such as chest pressure or tightness, unexplained breathlessness, fainting, or unusual fatigue on effort, demand immediate attention, true heart protection occurs through early and planned tests. While heart check-ups are routinely recommended starting at age 40, screening should ideally begin earlier, around ages 30 to 35, especially if risk factors are present.

Starting check-ups at age 30 is important because certain congenital and structural heart conditions remain completely silent for years, and early screening ensures timely, targeted treatment when it is most effective.

Regular screening helps detect and rule out underlying issues early, including congenital heart defects (commonly known as holes in the heart) and conditions such as Atrial Septal Defect (ASD), Ventricular Septal Defect (VSD), or Patent Ductus Arteriosus (PDA). Structural and muscle diseases, on the other hand, include valve disorders, heart muscle weakness, or abnormal thickening of the heart walls (e.g., Hypertrophic Obstructive Cardiomyopathy (HOCM)).

Key Risk Factors

In addition to age, patients should seek a heart check-up sooner if they have any of the following risk factors:

  • Strong family history of premature heart disease in immediate relatives.
  • History of active or past smoking and tobacco use.
  • Metabolic conditions such as diabetes, hypertension, or elevated blood cholesterol.

Excess body weight, especially central or abdominal obesity. Excess body weight damages the kidneys, leads to fat deposits in the liver and increases the risk of developing diabetes, and ultimately increases the strain on the heart and blood vessels (cardiovascular system). These interconnected conditions are known as Cardiovascular-Kidney-Metabolic (CKM) syndrome and include heart disease, kidney disease, diabetes, stetotic (fatty) liver disease, and obesity.

Effective weight and metabolic management, through modern options such as oral or injectable GLP1 therapies, can improve long-term heart health.

Tailoring care

A heart check-up can involve several tests, from blood tests to invasive or non-invasive ones (with/without needles, catheters, or probes entering the body). The most common blood tests include fasting and post-prandial or after-meal blood sugar (FBG/PPBG), HbA1c (glycated haemoglobin), lipid and thyroid profile, and kidney function tests. Non-invasive cardiac tests include electrocardiogram (ECG), 2D echocardiogram, and ultrasound. However, not everyone needs all of them.

Diagnostic tests should be customized based on the person’s age, symptoms, and individual risk score. Hence, skip the urge to self-order commercial diagnostic packages online. Instead, take the most important step towards protecting your heart by talking to your doctor. A personalized assessment can help determine which tests, if any, are appropriate for you, so that you can focus on the right steps to keep your heart healthy.

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