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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Prostate Cancer: Low Testosterone May Predict The Disease

Updated May 31, 2026 | 04:00 PM IST

SummaryNew research has found that low testosterone levels can cause extreme progression in high-grade prostate cancer. The study evaluated 924 men between 2005 and 2024.
Prostate Cancer: Low Testosterone May Predict The Disease

Credits: Canva

A new retrospective cohort study claims that men with low testosterone levels may face a greater risk of developing higher-grade disease; the data came from undergoing active surveillance (AS) for localised prostate cancer.

The study evaluated 924 men who participated in AS between 2005 and 2024 to find out if lower serum testosterone levels are connected with Grade Group (GG) progression.

The participants in this study had an average age of 63.6 years, with a mean baseline testosterone level of 394 ng/dL. About 29% of the patients at the AS had testosterone levels at ≤300 ng/dL, which was a benchmark to define low testosterone.

The study finds that having lower testosterone may lead to progression to GG2 disease and faster progression to GG3 or higher. The researchers found at the AS that men with testosterone levels ≤300 ng/dL had a 61% higher risk of higher progression than men with high testosterone levels.

What Is Prostate Cancer?

The gland in the male reproductive system that makes seminal fluid is the prostate. This is the most common type of slow-growing cancer in men, which sees the abnormal growth of cells in the gland; if detected early, it is very much curable. Some early-stage symptoms of the disease are blood in the urine or semen, trouble urinating, and erectile dysfunction, and if you’re asking yourself, why you?

You could probably blame age, family history, or lifestyle choices. While we cannot change the ‘why’, we can master the ‘how’ of finding the right treatment in time. Step 1: Rule out the possibility of cancer with a simple Prostate-Specific Antigen (PSA) blood test.

In the last 10 years, technology and innovation have revolutionized the diagnostics and treatments of the disease. Scientists from across the world are working around the clock, making marked improvements in treating prostate cancer.

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World Multiple Sclerosis Day: 10-Point Declaration Calls For Recognition Of Invisible Disabilities In India

Updated May 30, 2026 | 11:00 PM IST

SummaryDelayed access to insurance, high out-of-pocket costs, limited awareness of available entitlements, and the absence of comprehensive patient data continue to create barriers to timely care for patients with multiple sclerosis.
World Multiple Sclerosis Day: 10-Point Declaration Calls for Recognition of Invisible Disabilities in India

Credit: iStock

Multiple Sclerosis is a chronic and progressive neurological condition affecting an estimated 1.5–2 lakh people in India, and remains one of the country's most overlooked invisible disabilities.

Many of its symptoms, including fatigue, cognitive impairment, chronic pain, visual disturbances, and bladder dysfunction, are often not outwardly visible, contributing to delayed diagnosis, barriers to disability recognition, insurance challenges, and difficulties in accessing long-term care and support.

Declaration at National Policy Dialogue

In a significant step towards strengthening disability-inclusive healthcare and social protection in India, policymakers, neurologists, disability rights advocates, insurance stakeholders, and persons living with Multiple Sclerosis (MS) today endorsed a landmark 10-point Declaration on Invisible Disabilities and Gender at the National Policy Dialogue organized on the occasion of World Multiple Sclerosis Day 2026.

The National Policy Dialogue was held under the theme, "Shaping Policy. Advancing Access. Improving Lives."

"India has made significant progress in recognizing the rights of persons with disabilities, and conversations such as these are essential to ensuring that our laws, policies, and institutions continue to evolve in ways that better reflect the lived experiences of people affected by conditions such as MS," said Menaka Guruswamy, Member of Parliament, Rajya Sabha.

Also read: President Donald Trump Remains In Excellent Health, Says White House

Barriers to Care and Support

Experts from the Multiple Sclerosis Society of India (MSSI) stated that for people living with Multiple Sclerosis, the challenges often extend far beyond the disease itself.

Delayed access to insurance, high out-of-pocket costs, limited awareness of available entitlements, and the absence of comprehensive patient data continue to create barriers to timely care.

Thus, they expect the Declaration to catalyze stronger insurance inclusion, better access to support systems, and a more robust national understanding of the true burden of MS in India.

The 10-Point Declaration

The Declaration on Invisible Disabilities and Gender outlines a roadmap to strengthen implementation of the Rights of Persons with Disabilities (RPwD) Act, 2016, and improve the inclusion of invisible neurological conditions within India's healthcare, disability, and welfare systems.

Key recommendations include:

  • Recognition guidelines for invisible and episodic disabilities under the RPwD Act.
  • Flexible disability certification for people with fluctuating conditions.
  • Inclusion of MS and other chronic neurological conditions within National Health Mission care pathways.
  • Expansion of the Indian MS Registry Network (IMSRN) into a broader national invisible disability registry.
  • Affordable access to disease-modifying therapies and long-term neurological care.
  • Expanded tele-neurology services across India.
  • Gender-sensitive diagnosis and treatment pathways.
  • Stronger digital monitoring of disability rights implementation.
  • Inclusive workplace policies for invisible disabilities.
  • A National Mission on Invisible Disabilities.
Read More: Bundibugyo Ebola Outbreak: WHO Identifies Experimental Treatments, Vaccines

Call for Stronger Policy and Healthcare Support

The declaration reflects a growing consensus among stakeholders that India's healthcare and social protection systems must evolve to better address invisible conditions that significantly affect an individual's functional ability, quality of life, and socioeconomic participation.

"Multiple Sclerosis is a complex, unpredictable, and lifelong neurological condition that requires early diagnosis, timely intervention, and sustained access to advanced therapies. While often simplified for patient understanding, the clinical reality is far more challenging and demands a nuanced approach to treatment and long-term care," said Dr. R.K. Dhamija, Distinguished Neurologist, Director, IHBAS, and Chair, National Task Force, NITI Aayog Brain Health Initiative.

"Investing in neurological care is not merely a healthcare expenditure; it is an economic imperative that helps prevent irreversible disability, reduces long-term care costs, and enables people to remain active and productive," Dr. Dhamija added.

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Early Warning Signs of Tobacco-Related Diseases That We Should Not Ignore

Updated May 30, 2026 | 08:52 PM IST

SummaryPersistent changes like the change in your voice pitch or constant throat irritation are not to be taken lightly, either; they could be signs of deeper problems arising.
Early Warning Signs of Tobacco-Related Diseases That We Should Not Ignore

Credit: iStock

For many people, tobacco does not begin as an addiction; it starts as a habit woven into ordinary moments of daily life. A cigarette shared with friends, a smoke break during a stressful day, or chewing tobacco after meals can soon become a routine that feels difficult to avoid.

While these habits may seem harmless in the beginning, tobacco slowly affects nearly every organ in the body, often giving subtle warning signs long before a serious disease is diagnosed.

When The Body Starts Giving Signals

These effects rarely manifest suddenly and usually come after years of prolonged use. It is this slow progress that leads most tobacco users to believe that "I am fine." But there are unmistakable signs of some diseases brought about by the use of tobacco that ought not to be dismissed:

  • The Persistent Cough: A cough that has lasted for more than two to three weeks, becomes progressively worse each day, and is associated with a wheeze.

  • Unexplained Fatigue: A person feeling breathless or unnaturally tired after having climbed a couple of stairs or walking a short distance can easily attribute this to general fatigue.

  • Weight Fluctuations: The unexplained drop in weight can also be caused by some diseases that tobacco is likely to inflict upon the body.

Changes Inside the Mouth

Oral cancer caused by tobacco often appears initially in the form of persistent mouth ulcers, white or red patches inside the mouth, and jaw stiffness. These painful and irritating conditions can be so subtle that a person is not concerned by them.

Persistent changes like the change in your voice pitch or constant throat irritation are not to be taken lightly, either; they could be signs of deeper problems arising. Seeking medical help when it is still in the superficial stages will not only decrease your chances of being treated with aggressive measures but may actually result in an easier way to fight the condition.

Beyond Lungs: Other Effects of the Illness

Tobacco affects much more than just the lungs, and many symptoms associated with chronic conditions often go unnoticed.

  • Cardiovascular Strain: Dizziness and chest heaviness are indications of heart problems caused by the presence of toxins in the body.

  • Physical Discomfort: Headaches or leg edema may sometimes be seen as manifestations of blood vessel disorders.

The Untapped Power of Prevention

The most important remedy at our disposal is not a complicated surgery but an accurate identification of such conditions at their superficial stage, allowing for minimal and non-invasive treatments.

The human body is an incredibly powerful machine at healing, and the instant the consumption of tobacco ceases, a chain of events kicks off that increases circulation and improves lung function.

If you ever find yourself dealing with a persistent cough, mouth ulcer, or undue fatigue, it is advisable to visit a specialist at the earliest to prevent future complications.

(By Dr Yash Mathur, Senior Head, Neck, Oral, and Robotic Onco-Surgeon at HCG Cancer Hospital, Borivali, Mumbai)

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