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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Polyendocrine Metabolic Ovarian Syndrome — PMOS: The New Name for PCOS

Updated May 14, 2026 | 07:00 AM IST

SummaryWhen a 16-year-old hears “Polyendocrine Metabolic Ovarian Syndrome”, she understands it’s not vanity or infertility alone. PMOS reminds every physician to check OGTT, lipids, BP, and mental health at age 18, not 45.
Polyendocrine Metabolic Ovarian Syndrome — PMOS: The New Name for PCOS

Credit: AI generated image

When the name misleads, the disease remains misunderstood. Hence, endocrinologists now propose renaming PCOS as Polyendocrine Metabolic Ovarian Syndrome or PMOS.

This is because the term “Polycystic Ovarian Syndrome” is considered a misnomer. The name makes it sound like the condition is only related to the ovaries. However, over 30% of such patients have normal ovaries. The root lies in the hypothalamus, pituitary, adrenals, pancreas, and adipose tissue — truly polyendocrine.

The cysts in the name are actually antral follicles. The real burden is insulin resistance, dyslipidemia, NAFLD, and a 2-fold higher cardiovascular risk by age 50.

Not just reproductive: PCOS is India’s commonest endocrine disorder — 1 in 5 young women. It drives diabetes, hypertension, depression, and infertility.

PMOS, the acronym, expands as:

P — Polyendocrine: HPO axis + adrenal + insulin + leptin dysfunction

M — Metabolic: Insulin Resistance, obesity, fatty liver, CVD risk

O — Ovarian: Anovulation, hyperandrogenic ovarian dysfunction remains key

S — Syndrome: Heterogeneous, lifelong

This aligns with the 2023 International PCOS Guideline that defines it as a “metabolic + reproductive + psychological disorder”. Yet patients are still told, “You just have cysts.” PMOS reminds every physician to check OGTT, lipids, BP, and mental health at age 18, not 45.

The bottom line is that by changing the name, it is possible to change the game. When a 16-year-old hears “Polyendocrine Metabolic Ovarian Syndrome”, she understands it’s not vanity or infertility alone.

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India Better Prepared For Hantavirus Outbreaks After COVID-19 Experience, Says Dr NK Ganguly | Exclusive

Updated May 13, 2026 | 10:00 PM IST

SummaryDr. NK Ganguly said that the One Health approach, which integrates human health, animal health, and environmental monitoring, is crucial to target the emerging infectious diseases, including hantavirus. He also stressed the need for strengthening monitoring systems for animals, vectors, and humans alike.
India Better Prepared For Hantavirus Outbreaks After COVID-19 Experience, Says Dr NK Ganguly | Exclusive

Credit: AI generated image/HealthandMe

India is better prepared to deal with potential Hantavirus outbreaks due to the healthcare infrastructure and quarantine systems established during the COVID-19 pandemic, according to Dr NK Ganguly, former Director General of the Indian Council of Medical Research (ICMR).

In an exclusive interview with HealthandMe, Dr Ganguly said that while isolated cases of Hantavirus have appeared in India in the past, especially in crowded peri-urban and urban settings in Kerala, large-scale outbreaks have largely been reported in countries such as China, Argentina, the UK, and the US.

Dr Ganguly said that India's healthcare system significantly improved after the deadly COVID pandemic.

“India is overprepared in a way that during the COVID-19, our system, even at the district level or in much more rural settings, got established,” he said.

He pointed out that hospitals now have access to ECMO, BPAP systems, ventilators, and oxygen management facilities to curb the spread in case of an outbreak.

Dr Ganguly also mentioned the availability of antiviral drugs and experimental vaccine efforts that could potentially be explored for hantavirus treatment. “There are some crude vaccines which are made here also,” he said.

He added that India’s quarantine systems and public health drills developed during COVID-19 would also help contain future outbreaks.

“I think India will be okay because of the sheer transmission dynamics of this virus,” he said.

Hantavirus is a zoonotic disease that primarily gets transmitted through contact with infected rodents or exposure to their urine, droppings, and saliva, though rare cases of person-to-person transmission have also been reported.

According to the World Health Organization (WHO), 11 cases — including three deaths — have been confirmed so far. However, additional suspected and confirmed cases are likely to emerge across countries.

Also read: Hantavirus Can Linger Indoors, Spread Through Contaminated Dust, Says Infectious Disease Expert

Importance Of One Health

The One Health approach is critical in understanding and containing outbreaks like hantavirus, Dr Ganguly said.

The One Health approach, which integrates human health, animal health, and environmental monitoring, is also crucial to target the emerging infectious diseases, he noted.

Further, the noted microbiologist stressed the importance of strengthening surveillance across humans, animals, and the environment.

He explained that disease surveillance requires collaboration between bird specialists, forest experts, environmental scientists, and mammologists, especially for tracking zoonotic infections such as avian flu and hantavirus.

“In avian flu, birds follow special migration routes, so we needed bird specialists, forest experts, environmental experts, and mammologists,” Dr Ganguly said.

The expert also highlighted the growing challenge posed by shrinking spaces between humans and animals and the role of antimicrobial resistance (AMR) in emerging disease threats.

“Animal health is equally important. We need to maintain them, track their movements, and do surveillance,” he said.

Need To Track Climate

Dr Ganguly also warned that rising temperatures and shrinking boundaries between humans and animals could increase the risk of future infections.

“It is an environmental infection. With the rise of temperature, more hantavirus infections occur,” he told HealthandMe.

Why India Must Boost Surveillance

Calling surveillance one of the most critical tools in outbreak prevention, he urged India to strengthen monitoring systems for animals, vectors, and humans alike.

“We need to set up a dedicated surveillance for hantavirus in India, and we need to track hantavirus,” he said.

Dr Ganguly explained that to date, hantavirus cases in India have been detected accidentally during testing for respiratory infections or flu-like illnesses using advanced panel-based diagnostic systems.

“Like now these days, what happens is that when you are getting respiratory infection or flu-like symptoms, they put up a test system which is known as bio-fire or a thing like that which identifies 26 panels and gives the CT scoring of that, so from there, hantavirus emerged,” he said.

He added that India should strengthen surveillance tools and continue monitoring infections in animals, vectors, and humans alike.

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Prateek Yadav: What Was the Serious Lung Condition That Claimed His Life?

Updated May 13, 2026 | 08:00 PM IST

SummaryAccording to the autopsy findings, the provisional cause of death was recorded as “cardiorespiratory collapse due to massive pulmonary thromboembolism.” In simple terms, doctors said a large blood clot had blocked blood flow to the lungs, causing his heart and breathing to fail.
Prateek Yadav: What Was the Serious Lung Condition That Claimed His Life?

Credit: Canva

Prateek Yadav (38), the son of late Samajwadi Party founder Mulayam Singh Yadav, died due to a massive blockage in the blood vessels of the lungs, leading to a collapse of the heart and respiratory system, as revealed in the postmortem examination report.

According to the autopsy findings, the provisional cause of death was recorded as “cardiorespiratory collapse due to massive pulmonary thromboembolism.” In simple terms, doctors said a large blood clot had blocked blood flow to the lungs, causing his heart and breathing to fail.

What Is Pulmonary Thromboembolism?

An embolism is any object (clot, fat, air, tissue) traveling through the bloodstream that becomes stuck, blocking blood flow. A thromboembolism is a specific type of embolism where that travelling object is a piece of a blood clot (thrombus) that has broken off from its original site.

It is a life-threatening condition that happens when a blood vessel in the lungs is blocked by a blood clot.

The common symptoms may include:

  • Difficulty in breathing
  • Chest pain
  • Cough up blood

The blood clot starts in a deep vein in the leg and travels to the lung in most cases. Rarely, the clot forms in a vein in another part of the body, noted Mayo Clinic. When a blood clot forms in one or more of the deep veins in the body, it is called a deep vein thrombosis or DVT.

Other symptoms of pulmonary embolism include:

  • irregular heartbeat
  • lightheadedness or dizziness
  • excessive sweating
  • fever
  • leg pain or swelling, usually in the back of the lower leg
  • clammy or discolored skin
As per the Cleveland Clinic, about a third of people with a pulmonary embolism die before diagnosis and treatment, highlighting the condition's severity.

Also read: Your Desk Jobs May Impact Fertility, Not Just Waistlines, Say Experts

Lung Infection Claims Life of Karnataka Minister

Meanwhile, Karnataka's Planning and Statistics Minister, D. Sudhakar (66), passed away after a prolonged battle with a lung infection.

The most common lung infections that people experience are pneumonia, bronchitis, tuberculosis, influenza-related infections, and severe viral illnesses.

Experts noted that these lung infections cause fluid or pus to fill the air sacs, which prevents oxygen from entering the bloodstream.

"What may initially appear as a routine cough, fever, or chest infection can progress to severe pneumonia, respiratory failure, sepsis, or permanent lung damage,” Dr. Vikas Mittal, Director - Pulmonologist, CK Birla Hospital, Delhi, told HealthandMe.

Warning signs include

  • worsening breathlessness,
  • persistent fever,
  • chest pain,
  • bluish lips,
  • confusion,
  • falling oxygen levels should never be ignored.

Dr. Nikhil Rajvanshi, Consultant - Paediatric Pulmonology, Rainbow Hospital, Delhi, told HealthandMe that children may be more at risk of pulmonary infections as they can become dangerous quickly because their lungs and immune systems are still developing.

Common illnesses such as bronchiolitis, pneumonia, influenza, and other viral infections may rapidly lead to breathing difficulty, low oxygen levels, dehydration, and respiratory distress. Infants, premature babies, malnourished children, and those with asthma or congenital disorders are at higher risk of complications.

The experts called for

  • early medical evaluation
  • timely treatment
  • vaccination
  • good hygiene practices,
  • quit smoking,
  • maintaining immunity.

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