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.

End of Article

Untreated Eczema Could Lead To Chronic Asthma: Dermatologist Answers FAQs

Updated May 5, 2026 | 10:00 PM IST

SummaryEczema is a skin disorder, but how it contributes to asthma risk is relatively unknown.
Eczema

Uncontrolled eczema can also make sleep disorders worse. (Photo credit: AI generated)

Every year on May 5, World Asthma Day is observed, an event that aims at spreading awareness about the respiratory disorders. While asthma is becoming a common occurrence in India, citing excessive pollution and unhealthy lifestyle choices. But in a shocking revelation on the occasion, Dr. Gitika Sanodia, Consultant Dermatologist at Dr L H Hiranandani Hospital, Powai, revealed that leaving eczema untreated could lead to chronic asthma. Talking about it, Dr Sanodia answered some common FAQs about eczema and asthma.

Can untreated eczema cause asthma?

Yes, especially for those suffering from early childhood onset of moderate/severe atopic dermatitis. Eczema is not always limited to being solely a skin condition. In many cases, patients who suffer from eczema actually have one part of the atopic triad, which means the patient's skin barrier is dysfunctional, allowing for allergens to enter and sensitize the immune system. With time, the same tendency can impact other organs, causing allergic rhinitis or asthma. However, it must be noted that not all children with eczema develop asthma.

Why does everybody treat eczema as merely a skin problem?

Because of symptoms including itching, dryness, redness, scaling, and oozing from the skin. The families take care to control the acute phase of eczema while ignoring the patient's predisposition to allergies. Furthermore, atopic dermatitis is an inflammatory skin condition that is accompanied by impaired skin barrier function, immune dysfunction, and environmental factors. Moreover, according to DermNet, atopy is a term used for conditions where eczema, rhinitis, and asthma happen together.

Early signs for which parents and adults should be vigilant

Parents should worry if their children with eczema exhibit recurrent coughs, wheezing, noisy breathing, difficulties breathing during playtime, nighttime coughing, chest tightness, frequent sneezing, nasal blockage, allergic rhinitis, or exacerbation of symptoms following exposure to dust, animal dander, pollens, airborne particles, or fluctuating environmental conditions.

Is eczema therapy sufficient to prevent the development of asthma?

Successful treatment of eczema can help minimize the chances of allergens penetrating the skin barrier and allergic inflammation. Nonetheless, it would not be accurate to predict with certainty that eczema therapy will effectively prevent the onset of asthma. Literature recommends the prompt restoration of the skin barrier function, regular application of moisturizing agents, avoiding triggers such as fragrances and harsh soaps, managing flare-ups with prescription corticosteroid creams, controlling infections, and referring patients with severe eczema cases.

Is it a significant public health concern?

Yes. This condition is becoming more common, especially among children. If not controlled effectively, eczema will result in poor sleeping habits, difficulties with academic performance, reduced quality of life, greater susceptibility to infections, and potentially even links to other allergies. People lack sufficient information regarding the condition because they normally medicate themselves by applying whatever ointment or steroid to their skin.

End of Article

Is Your Home Making Your Asthma Worse? Doctors Highlight Indoor Triggers

Updated May 5, 2026 | 06:00 PM IST

SummaryFrom bedding to pets to scented candles and furry friends, asthma triggers can be found indoors. Doctors urged patients to identify their personal triggers and act early, because managing their indoor environment is just as critical as managing their medication.
Is Your Home Making Your Asthma Worse? Doctors Highlight Indoor Triggers

Credit: AI generated image

Asthma is often thought of as an "outdoor" problem, with triggers such as smog, pollen, or car exhaust. But for many, the real danger may be sitting right there on the sofa or hiding under the sink.

The chronic condition affects over 260 million people. It is also responsible for over 450,000 deaths each year worldwide.

If you're doing everything right with your inhaler but still feel that tightness in your chest, it’s time to look at silent indoor triggers.

1. The Bedding "Dynasty"

“It’s a bit unsettling, but your mattress is likely home to millions of microscopic dust mites. They love the warmth and humidity of a bed. You won't see them, but you’ll feel them,” Dr. Sandeep Nayar, Principal Director & HOD - Chest & Respiratory Diseases, BLK Max Super Speciality Hospital, told HealthandMe.

The Fix: Don’t just wash your sheets; use hot water (60°C). If you haven't encased your pillows in allergen-proof covers yet, make that your priority this weekend.

2. Moisture is the Enemy

Dr Nayar said mold isn't always a giant green patch. It hides in the "sweat" behind your wallpaper or the damp corners of a bathroom that doesn't vent well. If a room smells even slightly musty, mold spores are likely in the air.

The Tip: Keep your home's humidity below 50 per cent. A simple dehumidifier can sometimes do more for your lungs than an extra dose of medicine.

3. It’s Not Just the Fur

Many people think "hypoallergenic" pets are the cure. It’s actually a protein in pet saliva and skin flakes (dander) that causes the flare-up.

The Reality: Even if you keep the dog off the bed, dander travels on your clothes. HEPA air purifiers are a must-have if you share your home with a furry friend.

4. The "Clean" Smell Myth

That "fresh lemon" scent or your favorite scented candle? Those are Volatile Organic Compounds (VOCs). To a sensitive lung, those chemicals are irritants, not cleaners.

The Switch: Move toward fragrance-free products. If a cleaning spray makes you cough, your body is telling you everything you need to know.

5. Urban Uninvited Guests

In cities, cockroach droppings are a massive, often ignored asthma trigger. Their proteins mix with household dust and get kicked up every time you walk across the floor.

The Strategy: Seal the cracks in your walls and keep the kitchen bone-dry.

Other asthma triggers include dust mites, pet dander, indoor smoke, and strong cleaning agents that can worsen symptoms over time

How To Prevent Indoor Asthma Triggers

Dr. Manisha Mendiratta, Director & Head - Pulmonology, Sarvodaya Hospital, Faridabad, told HealthandMe that the key is prevention through simple, consistent habits. To make a meaningful difference, the expert urged people to

  • ensure good ventilation,
  • reduce indoor humidity,
  • clean soft furnishings regularly,
  • avoid aerosol-based products.
  • ise air purifiers,
  • keep windows open when possible,
  • creating a smoke-free space.
“Managing asthma is about more than just a prescription. It’s about making your home a place where your lungs can finally relax,” Dr Nayar said.

“Most importantly, patients should identify their personal triggers and act early, because managing their indoor environment is just as critical as managing their medication,” added Dr. Mendiratta.

End of Article

Revolutionary Blood Test May Detect Multiple Cancers From a Single Sample

Updated May 5, 2026 | 02:28 PM IST

SummaryBeyond cancer detection, MethylScan, which works by analyzing cell-free DNA, may also help identify various liver conditions and organ abnormalities by analyzing DNA fragments circulating in the bloodstream.
Revolutionary Blood Test May Detect Multiple Cancers From a Single Sample

Credit: Canva

Cancer is a complex disease, and its diagnosis often involves multiple tests, procedures, and high costs. Patients frequently undergo several blood draws and investigations before a clear result is reached.

Now, a revolutionary new low-cost test has shown promise in detecting multiple cancers using just a single blood sample.

Beyond cancer detection, the test may also help identify various liver conditions and organ abnormalities by analyzing DNA fragments circulating in the bloodstream.

The test, developed by scientists at the University of California, Los Angeles, is known as MethylScan. The novel test works by analyzing cell-free DNA, tiny fragments of genetic material released into the blood when cells die.

In early tests, MethylScan detected about 63 per cent of cancers across all stages and roughly 55 per cent of early-stage cancers.

The test, described in the journal Proceedings of the National Academy of Sciences, could offer a powerful and more affordable approach to early disease detection and comprehensive health monitoring.

“Early detection is crucial,” said Dr. Jasmine Zhou, Professor of Pathology at UCLA Health.

“Survival rates are far higher when cancers are caught before they spread. If you detect cancer at stage one, outcomes are dramatically better than at stage four,” Dr Zhou added.

How Does The New Cancer Test Work?

MethylScan studies DNA methylation—chemical tags on DNA that reflect tissue health and can change when disease develops.

Since most circulating DNA comes from healthy cells, advanced machine learning is used to identify subtle disease signals.

The New Cancer Test Is A Health Radar

In the study, MethylScan analyzed blood samples from 1,061 people, including patients with liver, lung, ovarian, and stomach cancers.

For multi-cancer detection, the test achieved a high level of overall accuracy. At a specificity of 98 per cent, meaning few false positives, it detected about 63 per cent of cancers across all stages and roughly 55 per cent of early-stage cancers.

The test also performed well in liver cancer surveillance among high-risk individuals, including those with liver cirrhosis or HBV. It detected nearly 80 per cent of cases at a specificity of just over 90 per cent, meaning a less than 10 per cent false positive rate.

The blood test could also distinguish between different types of liver disease, including viral hepatitis and metabolic-associated liver disease. It correctly classified about 85 per cent of patients, suggesting blood-based DNA testing could reduce the need for invasive liver biopsies.

In addition, the researchers noted that MethylScan can work like a health radar for the body. By reading DNA signals in the blood, it can tell when specific organs, such as the liver or lungs, are under stress or damaged, even without knowing the disease in advance.

“This study demonstrates that blood-based methylation profiling can deliver clinically meaningful information across multiple diseases,” said Zhou. “It’s an exciting advancement that brings us closer to realizing the dream of a single assay for universal disease detection.”

End of Article