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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Flu Vaccine: Why October Is A Good Time To Get Your Family Vaccinated

Updated Oct 12, 2026 | 09:09 PM IST

Summary​Healthy adults and children, as well as people with underlying conditions, can benefit from flu vaccination. Influenza can cause pneumonia, hospitalization and other severe complications.
Flu Vaccine: Why October Is A Good Time To Get Your Family Vaccinated

Credit: iStock

With flu season setting in across countries, including the US and the UK, doctors are urging people to get their annual flu shots. October offers an opportunity to build protection before winter flu activity increases.

The UK Health Security Agency (UKHSA) reported above-average flu activity and urged at-risk groups to get vaccinated. England's flu vaccination program last winter is estimated to have prevented about 100,000 hospital admissions and 7,000 deaths.

The US Centers for Disease Control and Prevention (CDC) recommends annual flu vaccination for everyone aged six months and older. The seasonal vaccine targets influenza A(H1N1), A(H3N2) and B/Victoria viruses.

In September, the Indian Medical Association (IMA) also highlighted annual influenza vaccination and gaps in adult immunization.

Why Is October A Good Time To Get Vaccinated?

Also read: Flu Activity Rises Early In US, UK And Japan: Why Experts Urge Vaccination Before Winter

The flu vaccine takes about two weeks to build protection, making October a good time to get vaccinated before winter, Dr. Bhawna Malik, Senior Consultant-Neonatologist and Pediatric Intensivist at Motherhood Hospitals, Greater Noida, told HealthandMe.

In India, flu activity can increase between January and March. Vaccination in October allows time for immunity to develop before this period.

However, October is not the only option. Dr. Vikas Maurya, Senior Director and HOD, Pulmonology, Fortis Hospital, Shalimar Bagh, told HealthandMe that vaccination can also be taken between April and mid-June, ahead of another period of flu activity from July to September.

He said one dose annually is generally sufficient, with timing depending on local flu patterns and the vaccine used.

Who Should Get The Flu Vaccine?

Healthy adults and children, as well as people with underlying conditions, can benefit from flu vaccination. Influenza can cause pneumonia, hospitalization and other severe complications.

Older adults, particularly those aged 65 and above, and people with diabetes, heart disease, kidney or liver disease, asthma or chronic obstructive pulmonary disease (COPD) face a higher risk of complications.

“Flu vaccination doesn't protect just yourself against the risk of having influenza but it also prevents transmission of infection to other vulnerable people around ourselves like little ones, elderly family members and people with medical conditions,” Dr. Malik said.

Dr. Mohit Bhardhwaj, Consultant, Pulmonology, PB Health, Gurugram, told HealthandMe that annual vaccination helps protect individuals and reduce transmission, as flu viruses change and vaccine protection can decrease over time.

Flu Vaccine Schedule For Children And Adults

Read More: Flu 2026: Symptoms To Watch For As New Season Begins

The vaccine can be administered from six months of age. The schedule depends on age and previous vaccination history.

  • Children aged six months to eight years: Some children receiving the vaccine for the first time need two doses at least four weeks apart.
  • Children aged nine and above: Annual vaccination is generally recommended.
  • Adults: One dose each flu season is generally recommended.
  • Infants younger than six months: Cannot be vaccinated directly.

Dr. Malik recommends vaccination for parents, siblings and caregivers to help reduce the risk of transmitting influenza to infants who are too young to receive the vaccine.

Are There Any Side Effects?

Most flu vaccine side effects are mild and may include injection-site pain, redness or swelling, fever, headache, body aches and tiredness. These generally settle within a few days, Dr. Bhardhwaj said.

A cooling pack or an ice pack wrapped in cloth may help relieve injection-site discomfort. Nasal vaccines may cause a stuffy nose, cough or headache, Dr. Maurya noted.

The injected flu vaccine cannot cause influenza. Anyone experiencing persistent fever, breathing difficulty or unusual symptoms should seek medical advice. Those with a history of serious allergic reactions to a previous flu vaccine should consult their doctor before vaccination.

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Migraine Is More Than A Headache: Lancet Review Explains What Happens In The Brain During Attacks

Updated Oct 12, 2026 | 04:00 PM IST

SummaryA recent Lancet review explains that symptoms of migraine extend beyond severe headache. It studies the complex interactive mechanism of the sensory networks in the brain that trigger different symptoms.
Migraine Is More Than A Headache: Lancet Explains What Happens In The Brain During Attacks

Credit: AI

A migraine attack is characterised by nausea, vomiting and sensitivity to light and sound. But early symptoms may surface long before the headache itself. Signs like fatigue, mood changes, food cravings and difficulty focusing may appear hours or even days before the pain.

The symptoms that occur during the attack reflect a complex neurological process that involves several interconnected brain networks, rather than just a headache.

A new Lancet Seminar review, looks deeper into how migraine develops, why its symptoms extend beyond head pain and how the better understanding of its biology are affecting treatment.

The study authors describe migraine as a chronic neurovascular disorder shaped by genetic susceptibility and interactions between the brain’s sensory networks, nerves, and blood vessels.

What Happens In The Brain During A Migraine Attack?

Also read: These Yoga Asanas Could Cure Your Migraine

Migraine is the result of the interaction of multiple systems responsible for processing sensory information and transmitting pain. Researchers are focusing more on other factors that drive migraine rather than just blood vessel narrowing or widening.

An important concept is the trigeminovascular system, which is a network involving the trigeminal nerve, tissues sensitive to pain that surrounds the brain and blood vessels. When this system gets activated, the patient experiences the peculiar head ache.

Chemical messengers called neuropeptides also play a key role. One of the most important is calcitonin gene-related peptide (CGRP), which participates in pain signalling in migraine. Treatments that target CGRP is an important development in migraine treatment and management.

The condition also involves changes in how the brain processes sensory information. This explains why light, sounds or smells can become intolerable during an migraine attack, and why some patients experience nausea, dizziness or difficulty concentrating along with severe headache.

Not an isolated abnormality triggering every symptom, migraine involves interactive neurological and vascular processes whose contributions can vary between individuals and across different phases of an attack.

Symptoms May Begin Before The Headache

Also read: Saba Ali Khan Opens Up About Brain Tumour: Can It Go Unnoticed If You Walk, Talk And Work Normally?

Migraine attacks typically occurs through several phases mostly:

1. Prodrome: Hours or days before the pain

The earliest phase can involve fatigue, yawning, mood changes, food cravings, neck stiffness and difficulty concentrating. The involvement of brain regions linked with homeostasis, including the hypothalamus, may help explain why an approaching attack can affect sleep, appetite, mood and other bodily functions.

2. Aura: Temporary neurological symptoms

Some people experience an aura before or during the headache. This can include flashing lights, zigzag patterns, blind spots, tingling or temporary difficulties with speech. Aura is associated with a phenomenon called cortical spreading depression, a wave of changing electrical activity that moves across the brain’s cortex.

3. Headache: Pain and sensory sensitivity

During the headache phase, activation of the trigeminovascular system contributes to pain signalling. Patients may experience moderate-to-severe, often throbbing pain, alongside nausea, vomiting and sensitivity to light, sound or smells.

Movement can aggravate the pain, making routine activities difficult. The headache phase can last several hours to as long as 72 hours.

4. Postdrome: After the pain subsides

The end of an attack does not necessarily mean the attack is over. Some people experience exhaustion, dizziness, body aches and difficulty concentrating for hours or days afterwards. These phases can overlap, and their timing and severity differ from person to person.

The Lancet review also highlights the role of genetic and epigenetic factors that contribute to migraine risk. They interact with complex neurological networks, helping explain why some people experience occasional attacks while others develop frequent or chronic migraine.

Episodic migraine is characterised by fewer than 15 headache days per month. Chronic migraine involves headaches on at least 15 days per month for more than three months, including migraine features on at least eight days each month.

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Breast Cancer: Know the Risks, Recognise the Signs & Get Checked

Updated Oct 12, 2026 | 02:30 PM IST

SummaryBreast cancer awareness involves understanding risk factors, recognising warning signs such as lumps or nipple changes, and seeking timely medical evaluation to improve early detection and treatment outcomes.
Breast Cancer: Know the Risks, Recognise the Signs & Get Checked

Credit: AI

Breast cancer is the most common cancer among women in India. According to various estimates, it accounts for about 26% of all cancers diagnosed among women, with nearly 2,00,000 new cases estimated in India each year.

Family history is not the only risk

Family history is an important risk factor, as some women inherit genetic changes that can increase their risk of developing breast cancer. Hereditary breast cancers can result from inherited genetic susceptibility, including mutations in high- or moderate-penetrance genes. BRCA1 and BRCA2 are among the best-known genes associated with hereditary breast cancer. Therefore, knowing family history is important.

But the absence of a family history does not mean that women are free from risk. In fact, around 80-85% of breast cancer cases occur in women with no known family history. These are generally referred to as sporadic cases.

The risk factors

Breast cancer risk factors can broadly be divided into those that cannot be changed and those that can potentially be modified.

Among the non-modifiable factors are age and certain reproductive and hormonal factors. Longer lifetime exposure to hormones such as oestrogen and progesterone can increase breast cancer risk. Early menstruation, later menopause and having a first pregnancy at a later age are some factors associated with longer hormonal exposure.

Potentially modifiable risk factors are largely lifestyle-related and include alcohol consumption, physical inactivity, excess body weight (particularly after menopause) and tobacco exposure. Maintaining a healthy weight, staying physically active, avoiding tobacco and limiting alcohol can help reduce the risk.

Also read: Amanda Peet’s Breast Cancer Wasn’t A Lump: What Was Her First Sign?

Five signs that should never be ignored

The five important warning signs include:

  • A new, hard lump in the breast or armpit, particularly if it is increasing in size.
  • A change in the size or shape of one breast, especially when it creates a new difference in breast symmetry.
  • Unusual nipple discharge, particularly spontaneous discharge that is clear or bloody.
  • Changes involving the nipple, such as a newly inverted nipple.
  • Changes in the breast skin, including thickening, dimpling, puckering or a change in its appearance or texture.

These signs do not automatically mean cancer. But they should not be ignored.

Also read: Mammogram May Spot Hidden Heart Risk That Doctors Miss In Women

Get checked if you notice a change

If you notice any of these signs, particularly a new or persistent change in your breast, do not ignore it or try to diagnose it yourself. Seek medical evaluation promptly. A doctor will assess the breast and, if necessary, recommend what is known as a triple assessment: a clinical examination, breast imaging such as ultrasound or mammography, and tissue diagnosis when required. In selected cases, an MRI may also be recommended.

Tissue sampling may involve Fine Needle Aspiration Cytology or a core/true-cut biopsy. Together, these assessments help determine whether a breast abnormality is benign or malignant. It is important to distinguish this from screening. Screening is done in women who do not have symptoms, with the aim of detecting breast cancer at an early stage. When a woman has a symptom or notices a new breast change, she needs diagnostic evaluation rather than simply screening.

Don't panic: most breast lumps are benign

Finding a lump can understandably cause anxiety. However, most breast lumps, particularly in younger women, are benign. Common causes include fibroadenomas, breast cysts and fibrocystic changes.

Fibrocystic changes are often influenced by hormonal fluctuations. A lump may become more prominent or painful one to two weeks before menstruation and become smaller or less uncomfortable after the period. Some women may also experience a feeling of heaviness or tenderness in the breast.

An injury to the breast can also result in tissue damage and inflammation, producing a lump-like area. Therefore, a lump should not be assumed to be cancer, but neither should it be dismissed without appropriate evaluation.

Early detection can make a significant difference in the successful management of breast cancer. Women should remember that having no family history does not mean they are not at risk. At the same time, a breast lump or other change does not necessarily indicate cancer. The key is to know your own breasts, be aware of the warning signs and seek timely medical evaluation whenever a new or persistent change is noticed.

By Dr Megha B - Surgical Oncologist in Trichy - Breast, GI & Cancer Surgery Specialist, Kauvery Hospital

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