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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Why Halloween Can Be Scary for Your Heart and Lungs: Other Health Hazards to Watch

Updated Oct 31, 2026 | 04:00 AM IST

SummaryHalloween activities can pose hidden health risks, from sudden scares and excessive sugar affecting heart health to asthma triggers, pumpkin-carving injuries and falls. Experts share precautions to help people celebrate safely.
Why Halloween Can Be Scary for Your Heart and Lungs: Other Health Hazards to Watch

Credit: AI image

From haunted houses and sudden scares to sweet treats and costumes, Halloween fun can come with hidden health risks, particularly for people with existing heart and lung conditions.

Experts explain how sudden fright, excessive sugar and common activities on Halloween, observed on October 31, can affect heart and lung health.

How Sudden Scares Can Affect Your Heart

A sudden scare activates the body's sympathetic nervous system, raising heart rate and blood pressure while constricting blood vessels.

This response is usually harmless in healthy people, but may pose risks for those with arrhythmias, coronary artery disease or a history of stents or heart surgery.

A racing heartbeat should settle after the scare. Persistent palpitations, dizziness, shortness of breath, chest pain or tightness, nausea, sweating or fainting warrant medical attention, says Dr Mohamed Gabr, cardiologist and electrophysiologist at Baylor College of Medicine.

In addition, excessive consumption of sugar candies during Halloween can contribute to obesity, diabetes, high blood pressure and unhealthy cholesterol levels. Cholesterol and plaque buildup in the coronary arteries can begin at a young age.

Also read: You Feel Healthy. But Plaque May Already Be Building In Your Arteries In Your 20s

Halloween Activities That Can Trigger Asthma

Halloween activities can expose people with asthma to several triggers. Ragweed pollen, mould on damp fallen leaves and cold, dry air can worsen symptoms during autumn, according to the American Lung Association.

Fog machines and dry ice effects in haunted houses can release water droplets and chemicals, including glycol-based solvents, that may irritate airways. Glitter machines, bonfire smoke, dust from stored costumes and decorations, and strong fragrances can also trigger symptoms.

Dr Rubabin Tooba, a pulmonologist with Northwestern Medicine, says these exposures may cause coughing, wheezing, breathlessness and chest tightness, particularly in people with asthma, severe allergies or COPD. Tight-fitting masks can also make breathing difficult.

Fear, excitement and laughter may trigger asthma symptoms in some people. Trick-or-treating can bring additional exposure to pet dander, scented candles, cigarette smoke and fireplace fumes.

Pumpkin Carving And Halloween Injuries

Read More: Why Are Asthma Cases Rising Among Young Kids? Early Symptoms Parents Must Not Ignore

The US Consumer Product Safety Commission (CPSC) estimates that an annual average of 3,200 Halloween-related injuries were treated in US emergency departments over a recent three-year period.

Pumpkin carving accounted for 55% of these injuries, while 25% were related to falls while putting up decorations, tripping on costumes or walking while trick-or-treating. The remaining 20% involved lacerations, ingestions, allergic reactions and other costume- or decoration-related injuries.

Children younger than 18 years accounted for 46% of injuries, with approximately 10% occurring in children aged 6 years or younger.

The Plastic Hand Trauma Unit at Royal Devon and Exeter Hospital has also treated patients with deep cuts, severed tendons and nerve damage from pumpkin carving, BBC reported.

How Can You Stay Safe This Halloween

  • Protect your heart: Be mindful of sudden scares if you have an existing heart condition. Seek medical attention for persistent palpitations, chest pain, breathlessness or fainting.
  • Moderate candy: Limit sugary treats and consider fruit alternatives.
  • Avoid asthma triggers: Ask about fog effects at haunted attractions and leave if you experience breathing discomfort.
  • Check costumes and decorations: Clean stored items before use and discard anything with mould or a musty smell. Choose breathable, open-face masks.
  • Use makeup carefully: Choose fragrance-free or hypoallergenic products and apply them in well-ventilated spaces.
  • Carry asthma medication: Keep your prescribed quick-relief inhaler and spacer handy. Watch for coughing, wheezing or chest tightness, and take breaks when needed.
  • Reduce infection risks: Practise good hand hygiene, stay home when sick and keep vaccinations up to date.
  • Carve pumpkins safely: Avoid kitchen knives. Use pumpkin-carving kits with serrated tools and make small, controlled cuts.

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Blood Pressure in Your Ankles? How the ABI Test Can Reveal Hidden Peripheral Artery Disease

Updated Oct 30, 2026 | 10:00 PM IST

SummaryThe ABI test compares blood pressure in the arms and ankles to detect poor circulation and peripheral artery disease (PAD). Early detection can help prevent complications and identify wider cardiovascular risks.
Blood Pressure in Your Ankles? How the ABI Test Can Reveal Hidden Peripheral Artery Disease

Credit: Cleveland Clinic

Blood pressure is routinely measured in the arms, but checking it in your ankles can also offer important clues about vascular health. An ankle-brachial index (ABI) test compares blood pressure readings in the arms and ankles to detect poor circulation and signs of peripheral artery disease (PAD).

Pain or cramping in the calves, thighs, hips or buttocks while walking, climbing stairs or exercising, which subsides with rest, could indicate PAD. The condition occurs when narrowed arteries restrict blood flow to the legs.

PAD can remain undetected for years, particularly in people without obvious symptoms. Early detection matters because the underlying atherosclerosis can also affect arteries supplying the heart and brain, increasing cardiovascular risks.

What Is an ABI Test and How Does It Detect Artery Disease?

The ABI test is a simple, non-invasive procedure that measures blood pressure in the arms and ankles using inflatable cuffs and a Doppler ultrasound device. The readings are compared to calculate the ankle-brachial index.

Dr. Samir Kubba, Director and Unit Head, Cardiology, Dharamshila Narayana Superspeciality Hospital, Delhi, explained to HealthandMe that the test assesses blood circulation in the lower limbs and can also indicate an increased risk of cardiovascular disease.

Dr. Anshul Kumar Jain, Director – Cardiology, CK Birla Hospital, Delhi, told HealthandMe that an abnormal ABI reading should not be viewed in isolation but as a potential warning sign requiring further cardiovascular assessment.

"What makes the ABI test particularly important is that PAD may remain undiagnosed for years, as some individuals experience no obvious symptoms," Dr. Samir said.

Others may experience leg pain while walking, cramps, numbness, cold feet or wounds that take longer to heal.

Dr. Anshul highlighted the wider implications of detecting PAD. "From a neurological perspective, identifying PAD is particularly important because underlying atherosclerosis can affect blood vessels supplying the brain as well as the heart. Reduced circulation may indicate an increased risk of cardiovascular events, including stroke," he said.

Who Should Consider an ABI Test?

The test may be useful for people at an increased risk of PAD, including:

  • Smokers and former smokers, particularly those over 50.
  • People with diabetes, high blood pressure or high cholesterol.
  • Individuals with a history of stroke or mini-stroke.
  • Adults over 65.
  • People with a strong family history of cardiovascular disease.

ABI is not a direct test for heart disease. It is a vascular assessment tool that helps identify PAD and may indicate wider cardiovascular risks. Abnormal results require further evaluation by a specialist.

How to Prepare for an ABI Test and What Happens During It?

No special preparation is required. You will be asked to lie on your back and rest for five to 10 minutes before the test.

A healthcare professional will place inflatable cuffs around your arms and ankles and measure blood pressure using a handheld Doppler ultrasound device. The procedure takes only a few minutes, and you can resume normal activities afterwards.

What Do ABI Test Results Mean?

The ABI is calculated by dividing the higher ankle systolic blood pressure reading by the higher arm reading. The resulting ratio indicates blood flow to the legs.

According to the Cleveland Clinic, ABI readings are interpreted as follows:

  • 1.0 to 1.3: Normal
  • 0.9 to 1.0: Borderline
  • 0.7 to 0.9: Mild PAD
  • 0.4 to 0.7: Moderate PAD
  • Below 0.4: Severe PAD

An ABI above 1.4 may indicate stiff or calcified arteries, often associated with ageing or diabetes. Such readings may require further testing.

People with diabetes or non-compressible arteries may also need a toe-brachial index (TBI) test, which measures blood pressure at the big toe.

How Is Peripheral Artery Disease Treated?

Treatment depends on the severity of arterial narrowing, symptoms and overall cardiovascular risk. Options may include:

  • Lifestyle changes: Dietary modifications, smoking cessation and management of cardiovascular risk factors.
  • Exercise: A supervised walking programme to improve circulation.
  • Medications: Drugs to manage PAD and associated risk factors.
  • Procedures or surgery: Interventions to restore blood flow in cases of severe arterial blockage.

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Psoriasis: Understanding The Skin Condition And Ways To Manage Flare-ups

Updated Oct 30, 2026 | 12:20 PM IST

SummaryDepending on your skin colour, you may see /red patches on lighter skin or dark patches with less pink tones on darker skin. Sometimes your skin colour can become temporarily different when the inflammation has subsided.
Psoriasis: Understanding The Skin Condition And Ways To Manage Flare-ups

Credit: iStock

Psoriasis is a long-term inflammatory skin disorder that impacts the immune system. It can cause itchy and unsightly areas of thick, flaky skin that can impact your confidence, relationships and everyday activities.

Symptoms can be erratic. Differ among individuals. Although a cure does not exist there are treatments that're effective. It is non-infectious.

What Happens In Psoriasis?

There is overactivity in the system causing an overproduction of skin cells. This causes a build-up of scaly patches known as plaques. The common form of psoriasis is plaque psoriasis. This type of psoriasis often appears on the scalp. It also often appears on the elbows. It also often appears on the knees. It also often appears on the back. This can cause itching, pain, breaking and bleeding. Nails can become pitted, with holes and can become thickened and lifted off the nail bed. Other forms can cause spots, shiny patches in areas of skin fold and pustules.

Depending on your skin colour, you may see /red patches on lighter skin or dark patches with less pink tones on darker skin. Sometimes your skin colour can become temporarily different when the inflammation has subsided.

Causes of Psoriasis

Whilst we do not fully understand the cause of psoriasis, it is caused by a combination of immune and environmental factors. If you have a family history, then you are more likely to develop psoriasis. Common triggers can vary between individuals, but infection, trauma, stress, smoking, excessive alcohol intake and certain medications can cause psoriasis or make symptoms worse.

Strep throat infections are commonly linked to guttate psoriasis (spot-like patches). Knowing your triggers can help; however, there may not always be a trigger.

Can We Reduce Flare-ups?

Unfortunately, there is no way to prevent psoriasis; however, keeping skin clean, taking medication and knowing your triggers can help reduce symptoms.

Have a shower using a cleanser and warm water. Apply a fragrance-free moisturiser to damp skin. Try not to scratch or rub your plaques. Try to avoid causing trauma to your skin and sunburn.

Keeping active, maintaining a weight if needed, quitting smoking and reducing alcohol can all improve your general health. Some people find keeping stress to a minimum helps; however, this cannot replace treatment. If your symptoms get worse when starting medication, let your doctor know. Do not stop taking your medication.

Treatments

This will depend on the type of psoriasis where it's how bad it is and how it is affecting your daily life. Your dermatologist will also take into consideration any medical conditions and if you have any joint symptoms.

Mild psoriasis can often be treated using various treatments. These can include steroids, vitamin D analogues and other medications. Steroids should be used at the correct strength and for the correct length of time depending on the area. Long-term steroids should be monitored.

Phototherapy uses specialist UV light, narrow-band UVB. This may be suggested if you have widespread psoriasis or topical treatments have not worked well enough. This should be monitored. Monitored. More severe or hard-to-treat psoriasis may need medication or biologicals. This can include Methotrexate, Ciclosporin, acitretin, or Apremilast. Biologicals work by targeting inflammatory pathways such as TNF, IL-17 and IL-23. This should be discussed individually with monitoring.

Talk to your doctor about any concerns you have regarding your treatment. This can include side effects, cost and difficulty sticking to a regimen. This will allow your doctor to put together a treatment plan.

Further Considerations

Some people with psoriasis can develop arthritis. If you have any pain, swelling, stiffness when waking up or heel pain, this should be assessed quickly. If left untreated, the inflammation can cause damage to your joints.

Psoriasis can put you at increased risk of developing disease, diabetes and other metabolic issues. This does not mean everyone with psoriasis will develop these conditions, but your doctor can advise what checks you need to do and how to keep your health in check. If your psoriasis is affecting your sleep, confidence, relationships or mood, let your doctor know. Counselling and other mental health support can be an addition to your treatment.

When To See A Doctor

If you have scaling changes to your nails or symptoms that are affecting your daily life, you should see a dermatologist. This will usually be diagnosed by looking at your skin and nails. Occasionally a skin biopsy may be needed.

If you have inflammation, scaling, pustules and are unwell or have a fever, you should seek urgent medical attention. This can indicate psoriasis and needs treating quickly. Whilst psoriasis can be unpredictable, there are treatments available. You deserve a treatment plan to help your symptoms.

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