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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What Started As Flu-Like Symptoms Left This 4-Year-Old In A Coma And Fighting to Walk

Updated Dec 15, 2025 | 08:53 AM IST

SummaryFour-year-old Sienna Dunion’s flu-like illness rapidly escalated into acute necrotising encephalopathy, a rare brain disorder, leaving her in a coma. Initially dismissed as a common flu, ANE caused severe neurological damage. After multiple surgeries, including removal of 60% of her intestines, Sienna now faces rehabilitation to relearn walking and speech.
What Started As Flu-Like Symptoms Left This 4-Year-Old In A Coma And Fighting to Walk

Credits: Canva

Four-year-old Sienna Dunion had initially flu-like symptoms, however her condition rapidly worsened, leading to a coma. What seemed like a simple flu was actually Acute Necrotising Encephalitis (ANE), a rare and severe brain disorder. After undergoing multiple surgeries and having removed 60% of her intestines, she is now struggling to walk and talk like from before.

How Did It Begin?

The first indication, which was very easy to miss was when she asked to return home five minutes after heading out to play with her scooter, reports The Independent. She had always been happy and exciting, so for her to return home so soon was not normal. She had also complained about feeling "cold and chilly" to her older sister, however, all of such symptoms were just seen as a common cold or flu signs.

As a result, her parents, Gary and Angelina Dunion, decided to keep her off school on Monday 17 November. Her temperature raised, no one was really concerned. All of these were cold and flu symptoms. She was still playing with her Barbies.

But it was on a Wednesday morning when she became unresponsive and had to make an emergency trip to A&E in Kettering. This is when she was induced into coma and diagnosed with the rare brain disease ANE.

Three weeks later, her family is facing the challenges to cope with the new changes which may take away how her daughter was before. Now, she requires years of intense rehabilitation to learn how to walk and talk again.

What is Acute Necrotising Encephalitis (ANE)?

Acute necrotizing encephalopathy (ANE) is a rare and serious brain condition that can cause sudden and rapid neurological decline after a viral infection, most often the flu or COVID-19. Because only a small number of cases have been reported worldwide, there is no standard treatment, making diagnosis and management especially difficult.

Sienna's father told The Independent, "For us, it’s really important that people can understand this has happened to a really healthy four-year-old girl who had no underlying issues. It has completely changed our lives overnight. What started as a flu has turned into a complicated brain disease and the last three weeks have just been horrendous.”

A Rare Diagnosis, But Urgent Care

Sienna had been feeling unwell on Monday and Tuesday, but it was on November 19 that her condition suddenly worsened. Her mother, Mrs Dunion, became alarmed when she tried to wake her and realised Sienna was unresponsive.

At A&E, doctors initially believed she was dehydrated after she tested positive for influenza. However, a CT scan showed unusual findings, including white lesions, while other test results remained unclear.

By 11 pm, doctors decided Sienna needed to be moved to the intensive care unit at Nottingham’s Queen’s Medical Centre. An MRI scan later confirmed a diagnosis of acute necrotising encephalopathy (ANE), a rare condition linked to viral infections.

Because of how uncommon the disease is, doctors designed a personalised treatment plan for her. This included plasma exchange, a procedure her family described as effectively washing her brain.

On Saturday, November 22, an ultrasound revealed a large build-up of fluid in her stomach. Sienna had to undergo emergency surgery, during which 60 per cent of her intestines were removed. Her father called it the hardest night of his life.

She later needed two more surgeries after air was found in her abdomen. Sienna now has a stoma bag and will live with short bowel syndrome for the rest of her life.

“The one thing doctors have been clear about is that she will not be the same when she fully wakes up,” Mr Dunion said. “She will need extensive rehabilitation.”

Although Sienna is awake, her father explained that she does not understand what is happening around her. She is weak, struggles to track with her eyes, and cannot eat on her own. The family is now fundraising to support her rehabilitation, including physiotherapy, speech and language therapy, feeding support, and changes needed at home.

A family struggling to cope

The couple also have a seven-year-old daughter, who is very close to Sienna. “They are best friends,” Mr Dunion said. “She keeps asking, ‘Where is Sienna? When can we be a family again?’”

He added that it is impossible to explain the seriousness of the situation to her. “I can’t tell her that she won’t be able to talk to her sister for a long time.”

“She was the most caring, easygoing four-year-old I’ve ever known,” her father said. “Even when she had a fever, she would check our temperature to make sure we were okay.”

He described her as a social child who loved being around other kids and had an infectious belly laugh. “We just don’t know if we’ll hear that laugh again,” he said.

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Is The Flu Shot Effective Against The H3N2 ‘Super Flu’ Spreading This Season?

Updated Dec 15, 2025 | 12:00 AM IST

SummaryWith the h3n2 “super flu” driving a sharp rise in flu cases, experts explain how effective this season’s flu shot is, who benefits most from vaccination, why protection differs by age, and why getting vaccinated still matters despite lower effectiveness against some strains.
flu shot superflu

Credits: Canva

The last thing anyone hopes to unwrap this Christmas is a heavy dose of flu. Yet as hospital admissions linked to the virus climb to levels not seen since 2010, this winter’s flu surge has pushed the NHS into what officials are calling a “worst-case scenario.”

Infections have jumped by over 50 per cent in just one week, and health leaders say there is still no clear peak. On average, 2,660 people a day were occupying hospital beds with flu last week, the highest figure ever recorded for this point in the season. Data from the UK Health Security Agency show the highest infection rates among children aged five to 14, followed closely by young people between 15 and 24. A number of schools have temporarily closed to curb outbreaks, while NHS leaders have advised people to consider wearing masks at work or on public transport, echoing guidance seen during the Covid years.

What Is Super Flu?

The strain driving the current spike has picked up the nickname “super flu” because it is believed to be a mutated form of influenza A (H3N2), known as “subclade K.”

Influenza H3N2 does not circulate as often as some other flu strains. Dr Simon Clarke, associate professor of cellular microbiology at the University of Reading, explains that the letters “H” and “N” refer to two proteins found on the virus surface, haemagglutinin and neuraminidase. “The numbers simply tell us which versions of those proteins are present,” says Dr Clarke. “It’s a way of grouping strains. This year, H3N2 happens to be the one in the lead.”

“H3 subtypes are relatively uncommon,” he adds. “That means fewer people have built up immunity. There is also evidence they spread more easily and mutate faster, which makes them harder for vaccines to keep up with.

“What we are seeing now is the outcome of that: cases rising sharply earlier than usual, with numbers likely to climb further as winter goes on.”

How Does Super Flu Differ From The Usual Variety?

Broadly speaking, flu falls into three main groups, A, B and C, according to Professor Ed Hutchinson from the Glasgow Centre for Virus Research. “Types A and B are the ones that make people seriously ill each winter. Influenza C circulates too, but it rarely causes severe disease. They are related, but not closely enough that immunity to one protects against the others,” he explains.

The concern is not that the virus has suddenly become far more deadly. Many people will catch it and recover without major problems. “The issue is scale,” Hutchinson says, as reported by The Telegraph. “When a virus spreads widely, even a small proportion of severe cases quickly adds up. That is what puts pressure on individuals and on the NHS.”

Last week, around 1,700 flu patients were in hospital, a 63 per cent increase on the previous week and more than 50 per cent higher than the same period last year. This rise is partly linked to a particularly aggressive subtype of the circulating H3N2 virus. “This strain is appearing earlier and spreading faster than we would expect, and immunity levels in the population are lower than usual for this stage of the season,” says Dr Aslam.

Is The Flu Shot Effective Against Super Flu?

Recent figures suggest the flu vaccine cuts the risk of hospital admission by roughly 30 to 40 per cent in older adults. That protection rate is lower than for some other vaccines, but it is in line with flu vaccine performance in past years. For that reason, advice has not changed. Vaccination remains the single most effective step people can take to protect themselves and to ease pressure on the NHS.

Why Does The Vaccine Have Different Effectiveness In Different Age Groups?

This season’s vaccines are still doing a solid job of preventing severe illness. Vaccinated children are about 70 to 75 per cent less likely to need a hospital visit or admission for flu. Among adults, the reduction is closer to 30 to 40 per cent.

One reason for this gap is the type of vaccine used. Children receive a nasal spray, while adults are given an injection. Research shows the nasal spray works particularly well in children but is less effective in adults, which is why different recommendations exist. So the comparison reflects not just age, but also different vaccines.

Another factor is prior immunity. Adults have encountered many flu viruses over their lifetime, so the added benefit of each new vaccine dose may be smaller than it is for a child. Even so, that extra protection still matters and can make a real difference.

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Think It’s Just Flu Or A Cold? This Cough Could Actually Be Covid

Updated Dec 14, 2025 | 09:00 PM IST

SummaryThe UK is facing an unusually early and severe flu season, driven by a more aggressive A(H3N2) strain that experts are calling “super flu.” This highly contagious virus is spreading faster than usual, raising concerns for hospitals and vulnerable populations.
COUGH COVID

Credits: Canva

A medical expert has revealed that you might be able to tell which winter illness you’re dealing with just by the type of cough you have. According to Dr. Rupa Parmar, a GP and medical director at Midland Health, coughing can present differently depending on whether you have a cold, flu, or COVID-19. During the winter months, certain infections become more common. Viruses spread more easily in cold weather, and spending more time indoors with others makes transmission more likely.

Still, it can be tricky to identify exactly what’s wrong because symptoms often overlap. Dr. Parmar advises: “There are some key differences between a cold, Covid, and flu that make it easier to tell them apart. But if you’re unsure, always check with your doctor. It’s better to be safe when it comes to your health.”

Cold and Flu

Dr. Parmar explained: “A cold usually causes a mild cough, while a flu cough is typically dry.” According to the NHS, cold symptoms develop gradually over two to three days. In contrast, flu symptoms “come on very quickly,” with a dry cough being a key sign.

Covid

Covid can also cause a dry cough, but it is usually persistent. Dr. Parmar said: “Covid tends to trigger a dry, continuous cough. Many people cough for over an hour at a time or have three or more coughing episodes in a single day.”

The NHS defines this as: “A new, continuous cough—meaning you’re coughing a lot for more than an hour or have three or more coughing episodes within 24 hours.”

What Is ‘Super Flu’?

NHS officials are warning that the UK may be facing an unusually severe flu season. Cases have started a month earlier than usual, driven by a stronger strain of the influenza A(H3N2) virus, sometimes being called “super flu.” Despite its intensity, vaccines remain effective against this strain, offering protection to those who get immunized.

Other Key Covid Symptoms

Other signs of Covid to watch for include:

  • High temperature—you may feel hot, cold, shivery, or notice heat on your chest or back (you don’t always need a thermometer)
  • Loss or change of smell or taste
  • Shortness of breath
  • Feeling very tired or drained
  • Body aches
  • Headache
  • Sore throat
  • Stuffy or runny nose
  • Loss of apetite
  • Diarrhea
  • Nausea or vomiting

The NHS warns: “Covid symptoms can resemble those of other illnesses like colds or flu. Most people recover within a few weeks, but some may take longer. If you have a cough, pharmacists can offer guidance on treatment.”

If You Have Covid

The NHS advises staying at home and avoiding contact with others if you or your child:

  • Have a high temperature
  • Do not feel well enough to attend work, school, childcare, or daily activities
  • You can resume normal activities once you feel better or no longer have a high temperature.

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