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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This Natural Amino Acid In Your Mouth Can Prevent Tooth Decay And Cavities

Updated Jan 14, 2026 | 02:07 PM IST

SummaryArginine, an amino acid that is already present in saliva, can turn reduce acidity and turn harmful bacteria into protective, which can significantly reduce the risk of tooth decay and cavities. The scientists believe that the amino acid could be a promising new addition to oral hygiene products such as toothpaste or mouthwash
This Natural Amino Acid In Your Mouth Can Prevent Tooth Decay And Cavities

Credit: Canva

While doctors across the world recommend ensuring that fluoride and other protective minerals make up your toothpaste, your body produces its very own amino acid that protect your entire dental cavity.

Arginine, an amino acid that is already present in saliva, can turn bacteria from damaging to protective in your mouth, a study has found.

When sugars from food are broken down by the many bacteria living in the mouth, acids are produced that gradually damage tooth enamel and lead to cavities. This is known as dental caries. Over time, this acid dissolves tooth enamel and causes cavities.

However, researchers at Aarhus University in Denmark have discovered that regular arginine treatment can significantly reduced the overall acidity levels in the mouth and prevent tooth decay.

Yumi Del Rey, microbiologist at Aarhus, said: ""Our results revealed differences in acidity of the biofilms, with the ones treated with arginine being significantly more protected against acidification caused by sugar metabolism."

How Did The Study Take Place?

The Danish scientists recruited 12 participants with active caries and prepared specialized dentures for the collection of intact biofilms, spanning both sides of the jaw.

Volunteers were then asked to instructed to dip the dentures in a sugar solution for 5 minutes, immediately followed by distilled water (as placebo) or arginine for 30 minutes, one on each side. This was to be repeated three times a day, with arginine treatment done on the same side each time.

Sebastian Schlafer, professor at the Department of Dentistry and Oral Health, explained: "The aim was to investigate the impact of arginine treatment on the acidity, type of bacteria, and the carbohydrate matrix of biofilms from patients with active caries."

After 4 days of this process, the biofilms were developed and the dentures were removed for detailed analysis. The researchers compared dental plaques grown on customized dentures on both sides of each participant's mouth using a special pH-sensitive dye called C-SNARF-4.

How Does Arginine Work?

Biofilms treated with arginine showed a significantly higher pH (lower acidity), altered biofilm structure and reduced harmful bacteria, highlighting the amino acid's potential in preventing dental caries.

Additionally, the team also began to look into how arginine might be reducing acidity, by taking stock of which bacteria and sugars were present in each sample.

Biofilms treated with arginine showed lower levels of a sugar called fucose, while another sugar, galactose, was concentrated towards the outer surface of the biofilm, meaning both sugars were away from the tooth enamel.

After analyzing the DNA of bacteria present, the researchers found that arginine treatment significantly reduced a specific population of Streptococcus bacteria known to produce acid, while slightly increasing other bacterial strains that can metabolize arginine.

The scientists noted that while more research is needed into the arginine's effectiveness, the amino acid could be a promising new addition to oral hygiene products such as toothpaste or mouthwash.

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COVID Symptoms In 2026: NHS Warns Of A 'Bounce Back'

Updated Jan 14, 2026 | 01:12 PM IST

SummaryUK health officials warn COVID is rising again alongside flu and norovirus, adding pressure on the NHS. UKHSA data show higher COVID hospitalizations week on week. New Omicron subvariants Stratus (XFG) and Nimbus (NB.1.1) are circulating. Fatigue is the most common symptom, alongside respiratory, neurological and gastrointestinal issues this winter period.
COVID Symptoms In 2026: NHS Warns Of A 'Bounce Back'

Credits: Canva

Covid is returning, as the National Health Service, NHS UK warned that there has been a "bounce back" in respiratory viruses this winter, along with COVID too on the rise. While UK was already struggling with flu and norovirus on the rise, cases of COVID have also risen. The latest data from the UK Health and Security Agency (UKHSA) show that the number of patients in hospital beds with COVID per day has risen from 0.87 per 100,000, as compared with 0.77 per 100,000 the previous week.

NHS national medical director Professor Meghana Pandit said: “It’s clear that the worst is far from over for the NHS this winter, with hospitals again experiencing a rise in patients admitted with flu and other respiratory virus cases last week.”

What New COVID Variants Are We Dealing With In 2026?

Since the pandemic, there have been many variants of COVID. The virus has continued to evolve. Two new variants that caused the spike in cases in autumn were XFG, known as Stratus, and NB.1.1, known as Nimbus.

Stratus: It is a subvariant of Omicron variant and made of previous variants LF.7 and LP.8.1.2. It was first detected in a sample on January 27, 2025. Whereas, Nimbus was first detected on January 22, 2025. It also originated from the same omicron variant, which was the reason for spike in 2023.

The World Health Organization (WHO) describes stratus as a "variant under monitoring" after several countries in South East Asia reported a rise in new cases and hospitalizations with this variant being detected.

COVID Symptoms 2026: Fatigue Emerges As The Most Common Symptom

Among studies that focused on how symptoms appear together, fatigue stood out as the most consistently reported issue. It often occurred alone or alongside problems such as muscle and joint pain, brain fog, or breathlessness. Other symptom pairings that appeared frequently included loss of smell and taste, anxiety with depression, and various forms of musculoskeletal pain.

When researchers classified patients based on affected organ systems, respiratory problems were the most widespread, seen in about 47% of long COVID patients. Neurological symptoms followed at 31%, while gastrointestinal issues were reported by 28%. The authors stressed that these percentages reflect how often these clusters appeared within long COVID cases studied, not how common they are in the general population.

A smaller number of studies sorted patients by how severe their symptoms were, dividing them into mild, moderate, or severe categories using symptom scores, symptom counts, or quality-of-life measures. Three studies used clinical indicators for classification, including abnormal triglyceride levels and signs of restricted lung function on imaging.

As per the Centers for Disease Control and Prevention (CDC), here are the common COVID symptoms:

  • Fever or chills
  • Cough
  • Shortness of breath or difficulty breathing
  • Sore throat
  • Congestion or runny nose
  • New loss of taste or smell
  • Fatigue
  • Muscle or body aches
  • Headache
  • Nausea or vomiting
  • Diarrhea

How To Know If You Have COVID?

CDC says, look out for these signs:

  • Trouble breathing
  • Persistent pain or pressure in the chest
  • New confusion
  • Inability to wake or stay awake
  • Lips and nail beds may appear pale, grey or blue

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That 5 Minutes Of Extra Sleep Can Reduce Your Risk Of Death

Updated Jan 14, 2026 | 06:00 PM IST

SummaryStudies in The Lancet suggest that small lifestyle tweaks add years to life. Seven to eight hours of sleep, modest exercise, healthier diets, even five extra walking minutes or less sitting, lower death risk. Benefits are strongest for least active people, showing combined, achievable changes can significantly improve longevity population wide overall.
That 5 Minutes Of Extra Sleep Can Reduce Your Risk Of Death

Credits: Canva

Have you ever dread waking up in the morning and felt like you just need the five extra minutes of sleep? Study now shows that it can actually be helpful for your health. A study published in the Lancet journal eClinical Medicine suggests that seven to eight hours of sleep per day, more than 40 minutes of moderate to vigorous physical activity and a healthy diet is associated with over nine years of additional lifespan and years spent in good health.

“The combined relationship of sleep, physical activity, and diet is larger than the sum of the individual behaviors. For example, for people with the unhealthiest sleep, physical activity and dietary habits to achieve one additional year of lifespan through sleep alone would require five times the amount of additional sleep per day (25 minutes) than if physical activity and diet also improved a small amount,” said the international group of researchers from the UK, Australia, Chile, and Brazil.

In a separate study published in The Lancet, researchers from Norway, Spain, and Australia found that adding just five extra minutes of walking to a daily routine can reduce the risk of death by 10 percent for most adults. The study reported that it will also help the least active adults to reduce their risk of death by around 6 per cent.

How Was The Study Conducted?

The study, which analyzed data from over 135,000 adults, found that cutting sedentary time by just 30 minutes a day was linked to a 7 percent reduction in overall deaths if adopted by most adults who sit for around 10 hours daily. Among the most sedentary people, who sit for about 12 hours a day, deaths could fall by nearly 3 percent.

“These estimates show the broad public health impact of even small, positive changes in physical activity and reduced inactivity,” said corresponding author Prof Ulf Ekelund of the Norwegian School of Sport Sciences, Oslo.

Researchers stressed that the findings are not meant as personalized advice, but as evidence of potential benefits at a population level.

Speaking to The Indian Express, Dr Nicholas Koemel from the Mackenzie Wearables Hub at the Charles Perkins Centre, University of Sydney, leading researcher of another study that seconds that extra five minutes of sleep can in fact help people live longer, said, "While major lifestyle overhauls are often recommended, they may not always be achievable or sustainable. Our results suggest that modest, combined changes may offer meaningful health benefits, be more likely to be maintained over time and provide an important starting point for individuals who may otherwise find it difficult to initiate lifestyle change. Starting by reviewing our daily routines to identify where small, realistic tweaks can be made is an important first step towards improving long term health and longevity."

Research over the years has consistently shown that moderate to vigorous physical activity helps improve key markers of health, including blood pressure, blood sugar, body weight, and body fat. Building on this, a large multi-country analysis of cohort data explains that even small increases in daily physical activity can significantly reduce the risk of death from any cause. The biggest gains are seen among people who are least active, as regular movement leads to a sharp drop in mortality risk for them. If such habits are adopted widely across the population, the data suggest that nearly 10 percent of deaths in people in their 70s and 80s could potentially be prevented.

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