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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Rare Canine Tooth Found In Indian Teen’s Eyelid: What Is An Ectopic Tooth?

Updated Oct 17, 2026 | 12:11 AM IST

SummaryEctopic teeth have been documented in several locations, including the nasal cavity, chin and maxillary sinus, an air-filled cavity within the cheekbone. Previous reports have also described teeth in the lower part of the eye socket. However, this is the first reported case of an ectopic tooth in the superior orbit, the upper region of the eye socket.
Rare Canine Tooth Found In Indian Teen’s Eyelid: What Is An Ectopic Tooth?

Credit: Opthalmology Journal

Doctors in India’s southern state of Tamil Nadu surgically removed a fully developed canine tooth from the upper eyelid region of a 16-year-old boy. They described the case as the first reported instance of an ectopic tooth in the upper part of the eye socket.

The case was reported by specialists at Aravind Eye Hospital in Madurai in the journal Ophthalmology.

What Did The Doctors Find?

The teenager visited the hospital with painless swelling of his left upper eyelid that had lasted a month. He had no history of injury to the area.

During the examination, doctors noticed two firm, whitish projections beneath the swollen area near the inner side of the upper eyelid, the experts shared in the paper.

A computed tomography (CT) scan revealed a dense structure resembling a tooth, with a crown and root, originating from the roof of the left eye socket. It extended towards the tissues in front of the orbital septum, a thin barrier separating the eyelid from the deeper eye socket, and protruded outwards with two tooth-like points on its surface.

The projections' appearance and texture raised the possibility that they were teeth. Dr. Meghana Tanwar, a medical consultant at Aravind Eye Hospital, told Live Science that they had a “fairly smooth surface and were hard on palpation.”

The doctors surgically removed the structure. Examination confirmed that it was a mature canine tooth without teratomatous elements, consistent with an ectopic tooth in the upper part of the eye socket.

Also read: Hours Of Sitting, Gaming And Binge-Watching OTT? Doctors Warn Of Blood Clot Risk In Young People

What Is An Ectopic Tooth?

An ectopic tooth develops or emerges in an abnormal location. Some remain within the mouth but appear outside their usual positions in the dental arch, while others develop outside the normal arrangement of teeth.

The latter is particularly unusual. In this teenager's case, the tooth was located in the upper orbital region rather than within the normal dental arch.

Before confirming the diagnosis, doctors considered whether the projections could be associated with a teratoma, a type of tumor that can contain different tissues, including bone and tooth tissue. They also considered whether a foreign object might be lodged in the eyelid.

Imaging and examination of the removed structure helped establish that it was a mature tooth rather than tissue associated with a teratoma.

Why Is This Case Unusual?

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Ectopic teeth have been documented in several locations, including the nasal cavity, chin and maxillary sinus, an air-filled cavity within the cheekbone. Previous reports have also described teeth in the lower part of the eye socket.

However, the doctors said they could not find an earlier report of an ectopic tooth in the superior orbit, the upper region of the eye socket.

“To the best of our knowledge this is the first and only ectopic tooth reported in the superior orbit,” Tanwar told Live Science.

“This was a first not just for us but the world over,” she said of the case. “We were very surprised by it.”

What Causes Ectopic Teeth?

READ: Non-Healing Mouth Sores? This Silent Symptom Could Signal Oral Cancer, Warn Doctors

The doctors could not determine why the tooth developed in this unusual location.

Possible explanations for ectopic tooth development include abnormalities during development, genetic factors, infections and physical trauma. However, the cause in this case remains unknown.

Imaging did not reveal any additional ectopic teeth. Tanwar said the likelihood of the teenager developing another such tooth was low.

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‘Feels Like I’m A Few Days From Death’: Olympic Sprinter Beth Dobbin Says She Is Bedbound 22 Hours A Day

Updated Oct 16, 2026 | 09:31 PM IST

SummaryDobbin’s health declined after back-to-back COVID-19 and glandular fever infections in winter 2021-22. Despite worsening fatigue and muscle-gland soreness, initial tests found no cause. Her condition later deteriorated, leaving her struggling to stand and spending most of her time in bed.
‘Feels Like I’m A Few Days From Death’: Olympic Sprinter Beth Dobbin Says She Is Bedbound 22 Hours A Day

Credit: athleticsweekly.com

Beth Dobbin, who represented Great Britain at the Tokyo Olympics in 2021, now spends more than 22 hours a day in bed.

The 32-year-old retired from athletics in April 2026, describing her illness as “serious” and “life-changing.” She was later diagnosed with myalgic encephalomyelitis (ME), a chronic condition with no known cure or specific treatment.

Dobbin reached the 200m semi-finals at the Tokyo Olympics and won bronze in the 4x200m relay with Scotland at the 2022 Commonwealth Games in Birmingham.

“It's life-decimating like I can't even put into words,” she said. “I feel like I've lost everything.”

Beth Dobbin's Diagnosis with ME

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Dobbin’s health began deteriorating after back-to-back COVID-19 and glandular fever infections in the winter of 2021-22, the BBC

reported.

She experienced worsening fatigue, slower running times and soreness in the glands in her neck and armpits. Initial tests by British Athletics doctors failed to identify the cause.

Despite her symptoms, she continued training in 2022. At the European Championships, she false-started after losing all feeling in her legs while in the starting blocks.

Her condition subsequently worsened. She struggled to stand and spent most of her time in bed. After consulting four or five specialists, she was diagnosed with ME.

Dobbin has been confined to her house and bed since then. She gets out of bed only to eat and use the bathroom. Even conversations, bright lights or loud sounds can trigger a “crash” lasting days or, in severe cases, months. She has left the house just five times this year, the report said.

She now leaves home mainly for medical appointments and blood tests. Even conversations, bright lights and loud sounds can trigger a “crash” that lasts days or, in severe cases, months. She has left home just five times this year, according to the report.

What Is ME?

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ME, also known as chronic fatigue syndrome (CFS), is a complex, chronic illness that can cause severe fatigue, pain, sleep disturbances and problems with thinking and memory. Symptoms do not improve simply with rest, and there is no established cure.

Dobbin rejects the term “chronic fatigue syndrome” because she believes it understates the severity of the condition.

“I wish it was just fatigue, that would be a walk in the park,” she said. “It's so much more than that. If I thought of fatigue in my top 20 symptoms it might just make the cut.”

She described the illness as feeling as though her entire body “is shutting down; it feels like you are a few days from death”.

More than 400,000 people in the UK are thought to have ME, although some estimates put the number above one million. The illness varies in severity, with some people continuing to work or study while others require extensive care.

Dobbin’s illness has also taken an emotional toll on her family.

“I'm just so desperate to help her but I can't because there is nothing. I'd take her anywhere, I'd take her to America if I had to, but there's nothing,” her father, Jim, said.

Beth Dobbin Aims To Raise ME Awareness

Dobbin describes her future as “very bleak” but hopes that greater awareness will lead to better treatment options.

The emergence of long COVID, which shares some symptoms with ME, has brought renewed attention to the illness and increased research funding.

She also wants to highlight the experiences of patients who are dismissed or disbelieved.

“A lot of people that have this illness that I've spoken to have said to me 'I don't get believed, people think I'm lazy'. I've never experienced one person that doesn't believe me and that's because, why would an athlete just suddenly stop after 20 years?”

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H. pylori And Cancer: US Gastroenterologist Explains How A Common Stomach Infection Raises Risk

Updated Oct 16, 2026 | 05:00 PM IST

SummaryH. pylori is a known risk factor for stomach cancer, linked to an estimated 760,000 cancer cases worldwide in 2024. Dr Vivek Kaul from the University of Rochester explains the infection’s role in cancer development and the importance of early detection and treatment.
H. pylori And Cancer: US Gastroenterologist Explains How A Common Stomach Infection Raises Risk

Credit: iStock

Infections accounted for an estimated 2.3 million new cancer cases worldwide in 2024, or about 12% of all cancers diagnosed that year, according to a September 2026 study published in The Lancet Oncology. Among these, Helicobacter pylori (H. pylori), a bacterium that infects the stomach, was associated with an estimated 760,000 cancer cases.

A 2025 study by the International Agency for Research on Cancer (IARC), part of the World Health Organization (WHO), estimated that 76% of the 15.6 million stomach cancer cases expected over the lifetimes of people born between 2008 and 2017 could be attributable to H. pylori infection if prevention efforts do not improve.

Although infections can contribute to cancer development, they are not the only cause. Genetics, age and non-infectious factors also play a role, Dr. Vivek Kaul, Professor of Medicine in the Gastroenterology & Hepatology Division at the University of Rochester Medical Center, told HealthandMe in an exclusive interview.

“I think, generally speaking, I think H. pylori is a well-known carcinogen, mostly responsible for the development of gastric cancer,” Kaul said.

Is Cancer Increasingly Linked To Infections?

The findings highlight the contribution of infectious agents to the global cancer burden. However, Kaul cautioned against concluding that cancer is increasingly being driven by infections.

“But I don't think it's fair to say that, you know, we are moving towards a more infectious etiology for cancer,” he said.

“Cancer is a multifactorial disease state that develops, most commonly develops from genetic and from non-infectious causes,” Kaul added.

He explained that cancer development also depends on the ability of cells to defend themselves against external threats and genetic mutations.

“In many cases, cancer development comes primarily from genetic and age-related issues and boils down to the individual cell's ability, you know, to fight external attacks, such as from H. pylori type of agents or from genetic mutations,” he said.

Kaul also noted that other infectious agents have been implicated in cancer development.

How Does H. pylori Raise Stomach Cancer Risk?

H. pylori is a bacterium that infects the stomach lining and can persist for years. The infection can cause chronic inflammation and damage to stomach tissue, increasing the risk of gastric cancer.

According to scientists at the International Agency for Research on Cancer (IARC), part of the World Health Organization (WHO), H. pylori infection is responsible for an estimated 76% of stomach cancer cases worldwide. The infection often causes no noticeable symptoms, although some people may experience digestive complaints.

The bacterium can spread through contaminated food or water and close contact with infected individuals. In some cases, the infection can cause stomach ulcers. Because many infected people have no symptoms, testing may be needed to identify it.

Can H. pylori Infection Be Prevented From Progressing To Cancer?

The World Gastroenterology Organisation's global guidelines state that eradicating H. pylori before precancerous changes develop can help prevent gastric cancer. This evidence supports test-and-treat screening programmes for young adults in countries with a high disease burden and sufficient resources.

Testing can involve blood, breath or stool tests, depending on the clinical context. People diagnosed with the infection can receive treatment to eradicate the bacterium. Follow-up testing can then confirm whether treatment has worked.

Nobel laureate and gastroenterologist Dr Barry Marshall has also highlighted the potential for early treatment to reduce cancer risk.

“H. pylori is much more than an ulcer organism. If the infection persists for many years, it can cause chronic inflammation in the stomach and increase the risk of gastric cancer. That gives us an opportunity because this is a potentially preventable cause of cancer,” Marshall told PTI.

He stressed the need for wider testing, appropriate treatment and follow-up to ensure the infection has been cleared.

Other Digestive Cancers Are Also A Growing Concern

Beyond infection-associated cancers, Kaul highlighted the rising incidence of several digestive cancers.

“We know that esophageal squamous cancer is another example where we will be close to a million cases by 2035,” he said, pointing to the burden in East Asia, sub-Saharan Africa and South America, including India.

Kaul also identified liver cancer as a growing concern and noted the rise in colorectal cancer among younger people in Western countries. The increase in colorectal cancer among younger adults in the US contributed to recommendations to begin average-risk screening at age 45 rather than 50.

These trends underline the need to address infectious causes of cancer alongside other risk factors, while improving access to prevention, early detection and appropriate care.

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