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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Extreme Heat To Drive US Heart Disease Burden Up 200% By 2050: Study

Updated May 29, 2026 | 11:09 PM IST

SummaryThey found that the Pacific Northwest has the highest heat-related heart disease rate in the country. Southern states, however, are projected to see the steepest increases by 2050.
Extreme Heat To Drive US Heart Disease Burden Up 200% By 2050: Study

Credit: AI generated image

Higher temperatures in the US could increase heat-related heart disease by 200 per cent by 2050, according to an alarming study.

The research, published in JAMA Cardiology, predicts rising temperatures driven by climate change will dramatically increase heat-related heart disease in the US.

It is already known that extreme heat is detrimental to heart health and can potentially trigger heart attacks and other cardiovascular events.

"But this study is the first to map out exactly how bad the problem could get—county by county, across the US. It also highlighted how states with lower median household incomes are likely to face higher heat-related heart disease burden," said Gokul Parameswaran, research associate at the Case Western Reserve School of Medicine's Cardiovascular Research Institute and the study's lead author.

Regional Hot Spots

Researchers analyzed heart disease data in each county in the contiguous US from 2010 to 2016 to develop projections through 2050.

They found that the Pacific Northwest has the highest heat-related heart disease rate in the country. Southern states, however, are projected to see the steepest increases by 2050.

"Climate change is not just an environmental issue—it is a health equity crisis, and prioritizing vulnerable communities must be at the center of any heat mitigation strategy," said Salil Deo, associate professor in the Department of Surgery.

Also read: Global Temperatures Likely To Stay Near Record Levels For Next Five Years: WMO

The study also found that aging — independent of temperature increases — will contribute an additional 34 per cent increase in heat-related heart disease by 2050, simply because there will be more older adults by then.

Heat Events In The US

The study comes amidst more frequent heat events in the US, which is also lasting longer, and the temperatures during heat events are going up.

The past 10 years, from 2015 to 2024, were the hottest on record globally. But in cities across the United States, the average rate of extreme heat events increased from two per year in the 1960s to 10 per year between 2010 and 2020, according to Center for Climate and Energy Solutions (C2ES), a Washington-based NGO.

Also Read:‘Heat Dome’ Triggering Record-Breaking May Temperatures In France, UK, Spain

Additionally, as of 2024, the average length of heat-wave season in the US has increased by 46 days since the 1960s.

How Does Heat Raise Heart Risks?

According to the Centers for Disease Control and Prevention, when temperatures rise, the heart must work harder to keep the body cool, and the likelihood of developing sudden clots in the bloodstream increases.

Read More: Can Extreme Heat Trigger Heart Palpitations? Expert Explains Risks

This extra stress on the heart due to high heat may lead to heart attacks or sudden worsening of heart disease, especially in the elderly or those with prior heart conditions.

How To Tackle The Risk

  • Expanding green spaces and tree cover in urban areas could help reduce temperature-related adverse effects.
  • Expanding access to cooling centers and air-conditioning assistance programs for low-income communities can also help bridge the gap in underserved communities.

"Climate change is not a distant, abstract threat," said Sanjay Rajagopalan, director of the Cardiovascular Research Institute and chief of Cardiovascular Medicine at University Hospitals Harrington Heart & Vascular Institute.

"It is a present and growing danger to the hearts of every American, and it is coming for the most vulnerable among us first. The choices made today about greenhouse gas emissions, urban planning, and health care policy will determine whether tens of thousands of Americans live or die from heat-related heart disease by 2050," he added.

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FSSAI Introduces Stricter Quality Checks For Besan, Seafood, And Edible Oils: What You Should Know

Updated May 29, 2026 | 09:03 PM IST

SummaryFSSAI's draft regulations cover heavy metals, toxins, antibiotic residues, and quality standards for both commonly used foods and emerging edible products.
FSSAI Introduces Stricter Quality Checks For Besan, Seafood, And Edible Oils: What You Should Know

Credit: AI generated image

Amid increasing contamination and adulteration of food products, India’s food regulator has introduced new safety standards across a wide range of foods such as besan (gram flour), edible and cold-pressed seed oils, as well as prawns.

The draft regulations by the Food Safety and Standards Authority of India (FSSAI) cover heavy metals, toxins, antibiotic residues, and quality standards for both commonly used foods and emerging edible products, the Times of India reported.

The new regulations are expected to come into force on December 1.

What Has Changed Under The New Rules?

Under the new rules, the FSSAI has:

  • Expanded contamination standards related to lead and cadmium to include pulse flours such as besan and packaged mixes in addition to pulses.
  • Updated limits for aflatoxins — toxic substances produced by certain fungi — in oils, oilseeds, and ready-to-eat oilseed products.
  • Revised testing norms for arsenic in fish oils and updated standards for saffrole, a naturally occurring substance found in foods and beverages containing nutmeg and mace.
  • Introduced residue limits for antibiotics such as trimethoprim and oxolinic acid in seafood products, including shrimps, prawns, and fishery products.

New Standards For Seed Oils And Edible Seeds

In a separate draft notification, the FSSAI proposed quality and safety standards for lesser-used edible oils made from chilli, tomato, muskmelon, and okra seeds as demand rises for cold-pressed oils, seed-based snacks, and plant-based nutrition products.

The proposed norms require these oils to remain free from adulteration, harmful impurities, rancidity, and mineral oil contamination, while also prescribing limits for moisture, acidity, and metal content.

Also read: Can Beetroot Juice Help Lower Blood Pressure?

The draft rules also cover edible seeds such as watermelon, cucumber, pumpkin, sunflower, sesame, and flaxseed sold in raw, roasted, or salted forms, requiring them to be clean and free from insects, fungus, and visible contamination before sale.

FSSAI has invited public comments on the draft regulations for 60 days before finalization.

Crackdown On Food Adulteration

Further, in two separate incidents in Uttar Pradesh’s Ghaziabad and Muzaffarnagar, the state food regulator cracked down on food adulteration.

In Ghaziabad, the state food regulator seized 10 quintals of suspected paneer stored in unhygienic conditions. With contamination risks high, the joint team swiftly sampled the batch and destroyed the entire 1,000 kg consignment.

In Muzaffarnagar, food safety officials inspected an ice cream outlet. The drive focused on ice creams and ice candies to ensure they met regulatory standards. A total of three legal samples were collected.

Read More: Are Mangoes Safe for Oral Cancer Patients?

How Adulterated Foods Can Affect Your Health?

The FSSAI noted that hidden adulterants in everyday food can create serious concerns for consumers.

Food adulteration happens when there is an intentional addition of foreign or inferior substances to original food products.

A 2024 study published in SAGE Open Medicine noted various health impacts of adulterated food, including:

  • Cancer
  • Lathyrism
  • Liver disease
  • Cardiac failure
  • Kidney disease
  • Nervous system-related diseases

The study also noted that adulteration could lead to allergic reactions. Pregnant women, children, and the elderly are more prone to developing illnesses if adulterated food is consumed.

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Herbal Cigarettes Not Safe, Found High In Fine Particles And Lead: Study

Updated May 29, 2026 | 02:25 PM IST

SummaryThe study showed that leaf-wrapped herbal variants are the most hazardous. Basil-filled herbal cigarettes marketed as “100% natural” and “chemical-free” showed the highest lead concentration among all products tested.
Herbal Cigarettes Not Safe, Found High In Fine Particles And Lead: Study

Credit: IITGN

Do you smoke herbal cigarettes believing they are “natural”, “chemical-free”, and “tobacco-free”? You may be mistaken. New research, ahead of World No Tobacco Day 2026, has raised concerns over the growing popularity of herbal cigarettes, suggesting that herbal cigarettes are not safer than conventional cigarettes and may be equally harmful to health.

The new joint study by the Indian Institute of Technology Gandhinagar (IITGN) and the University of Illinois Urbana-Champaign (UIUC), US, has found that herbal cigarettes can produce emissions comparable to — and in some cases more harmful than — those generated by tobacco cigarettes.

The study, published in the Journal of Hazardous Materials, highlight significant health concerns surrounding herbal smoking products, many of which currently fall outside India’s primary tobacco control laws.

Leaf-wrapped Herbal cigarette Most Hazardous

The study compared emissions from two of India’s best-selling tobacco cigarette brands and four popular herbal cigarette varieties containing ingredients such as basil, clove, cinnamon, mint, green tea, water lily, and chamomile.

Two of the herbal products also used tendu (ebony) leaves as wrappers — the same material commonly used in bidis, India’s most consumed smoking product.

Also read: Global Temperatures Likely To Stay Near Record Levels For Next Five Years: WMO

Researchers analyzed the physical, chemical, and oxidative properties of mainstream smoke generated from the products. According to the study, herbal cigarette smoke released extremely fine particles and toxic compounds at levels similar to or exceeding those found in tobacco smoke.

“Our findings challenge the widely held belief that tobacco-free means risk-free. Emissions from herbal cigarettes are comparable to or exceed those from tobacco cigarettes on nearly every metric we measured. Leaf-wrapped herbal variants turned out to be the most hazardous of all the samples tested,” said Prof. Sameer Patel, Assistant Professor at IITGN’s Department of Civil Engineering and Chemical Engineering.

Fine Particles And Oxidative Stress

Further, the researchers combusted each cigarette inside a sealed automated two-chamber system designed to mimic human inhalation patterns, to decode particle size, chemical composition, and oxidative potential.

Shockingly, the team found that particles smaller than 500 nanometers — associated with cardiovascular and respiratory diseases — were emitted at nearly 20 per cent higher concentrations in herbal cigarette smoke compared to tobacco smoke.

The study also measured the “oxidative potential” (OP) of smoke particles — a marker of their ability to generate reactive oxygen species that contribute to inflammation, lung damage, and vascular disease.

According to the researchers, particulate matter from herbal cigarettes showed significantly higher oxidative potential than tobacco cigarettes. Tendu-leaf-wrapped variants recorded OP levels nearly 49 per cent higher than paper-wrapped products.

Notably, one basil-filled herbal cigarette marketed as “100% natural” and “chemical-free” showed the highest lead concentration among all products tested.

Prof. Vishal Verma, Associate Professor of Environmental Engineering at UIUC and co-author of the study, said the results are particularly significant because many consumers believe nicotine-free products are less harmful.

“That finding is important because many consumers associate nicotine-free products with reduced harm,” he said.

Concerns Over Regulatory Gaps

Read More: Can Sugary Drinks Cause Brain Aging?

Researchers also pointed to regulatory loopholes surrounding herbal cigarettes. India’s Cigarettes and Other Tobacco Products Act (COTPA), 2003, regulates tobacco products through health warnings, advertising restrictions, and public smoking rules. However, many products marketed as tobacco-free do not fall under the same regulatory framework.

Lead author Dr. Alok Kumar Thakur said several herbal cigarette brands claim therapeutic benefits, including relief from cough, anxiety, and sleep problems, despite limited scientific evidence on their safety.

“However, there is limited scientific evidence evaluating the emissions and toxicological impacts of these products,” he said.

The findings also align with the World No Tobacco Day 2026 under the theme, “Unmasking the appeal: countering nicotine and tobacco addiction.”

The researchers stressed the urgent need for evidence-based regulation and stricter oversight of alternative smoking products to prevent misleading health claims and protect public health.

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