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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Post-Menopausal Women Face A Higher Risk Of Fatty Liver Disease: How Falling Estrogen Levels Impact Liver Health

Updated Aug 21, 2026 | 02:41 PM IST

SummaryHormone replacement therapy (HRT), when initiated early in post-menopausal women for symptomatic relief, may offer secondary benefits by maintaining metabolic health.
Post-Menopausal Women Face A Higher Risk of c Disease: How Falling Estrogen Levels Impact Liver Health

Credit: iStock

It is a common belief that metabolic dysfunction-associated steatotic liver disease (MASLD)—formerly known as non-alcoholic fatty liver disease (NAFLD)—is primarily associated with diet, sedentary lifestyles, and obesity. However, there are other factors as well that affect this aspect. Post-menopausal women experience a significantly higher incidence and faster progression of fatty liver disease, even when maintaining a stable body weight.

In Pre-menopausal women, estrogen plays a central role in metabolism by promoting healthy fat accumulation in subcutaneous tissue (below the skin) rather than around internal organs; it also increases insulin sensitivity and suppresses liver inflammation.

After menopause, when estrogen levels drop, this protective function is lost; there is redistribution of fat leading to more fat accumulation around internal organs, including the liver, thus leading to increased chances of NAFLD and also increasing insulin resistance. Needless to say, with age, our metabolic rate also goes down, which also plays a role in this.

The important part lies not only in understanding the above but in going further in early detection and prevention of menopause associated NAFLD. As we know, fatty liver is a silent disease and often does not cause any signs and symptoms till a very advanced stage.

First and foremost is to change lifestyle with advancing age, changing both the dietary habits and physical activity. Regular screening and monitoring are warranted with blood tests, routine metabolic panels, keeping a tab on weight, sugar, and cholesterol levels, and a basic ultrasound of the abdomen. For someone already diagnosed with second or third stage fatty liver, a simple non-invasive FibroScan can help monitor and assess the response to treatment.

Coming to the treatment part of NAFLD in post-menopausal women, being primarily a lifestyle disease, the core of management also lies in managing lifestyle. Medicines are available for treating and controlling NAFLD in conjunction with lifestyle management. Hormone replacement therapy (HRT), when initiated early in post-menopausal women for symptomatic relief, may offer secondary benefits by maintaining metabolic health. However, HRT should always be initiated after proper evaluation and expert guidance.

NAFLD is a silent epidemic and primarily a lifestyle disease; knowing about it and knowing the triggering and precipitating factors helps with understanding and prevention better. Menopause, being a natural biological phenomenon in every female’s life, makes it essential for us to know how it affects our liver health and overall health as well.

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How Genetic and Genomic Testing Can Help Women Make Smarter Cancer Decisions

Updated Aug 21, 2026 | 07:30 AM IST

SummaryGenetic testing is usually performed on blood or saliva to look for inherited changes or genetic predisposition. Genomic testing is usually performed on tumor or blood samples to identify molecular features, enabling a better understanding of the tumor's biology and biomarkers.
How Genetic and Genomic Testing Can Help Women Make Smarter Cancer Decisions

Credit: iStock

Being aware of personal and family cancer risk may be a critical component in women's knowledge and empowerment to make appropriate screening, prevention and treatment decisions.

Cancer treatment is fast evolving. Doctors are now focusing more on the person than the location or type of cancer and are considering the personal attributes of the patient and the disease. Genetic/genomic testing can complement this and can offer something more that could inform personalised cancer care.

Genetic testing: Knowing your inherited risk

Genetic testing screens for changes in the genes that could be passed down from parents. Some genetic mutations passed down from parents can make a woman more likely to get breast or ovarian cancer.

Having such a genetic change does not mean that a woman will develop cancer. This information will help her and her doctor discuss screening, monitoring and preventive action (if applicable) to reduce her risk.

This information may be useful for family members who could be at risk and should talk to their health care provider about their own risk.

Genomic testing: Understanding the cancer better

There is a difference between genetic testing and genomic testing. Genetic testing is usually performed on blood or saliva to look for inherited changes or genetic predisposition. Genomic testing is usually performed on the tumour or blood to identify its molecular features to enable better understanding of its biology and biomarkers.

Cancer is not one disease and even two patients with the same type of cancer can have different biological characteristics, which can help doctors decide on the treatment and options that may be suitable for an individual patient.

Genomic testing could help to pinpoint features of a tumour that can be used to consider particular targeted treatments or other methods. But not all of them will be suitable or available to all patients based on the results of testing.

Why Awareness About Health Issues Is Important

For women, knowing their family history and discussing any concerns with a doctor can be an important starting point. Genetic or genomic testing should not be done simply because it is available. A specialist may recommend testing based on factors such as family history, age at diagnosis and the type of cancer involved.

It is also important to understand test results correctly. Genetic counselling and discussions with an oncology specialist can help women understand what their results mean and what they do not mean.

Ultimately, genetic and genomic testing is not about predicting the future with certainty. It is about giving patients and doctors more information to make better-informed decisions.

As cancer care moves towards greater personalisation, the freedom to know your risk can become a powerful part of taking control of your health—helping women move from fear and uncertainty towards awareness, informed choices and personalised care.

(Dr. Jyoti Wadhwa, Principal Lead, Medical & Precision Oncology, Apollo Athenaa Women’s Cancer Center)

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World Mosquito Day: How Dengue Can Damage Your Kidneys

Updated Aug 20, 2026 | 12:59 PM IST

SummaryDengue is typically associated with high fever, joint pain, and low platelet counts. However, severe dengue can affect the kidneys and lead to acute kidney injury (AKI).
World Mosquito Day: How Dengue Can Damage Your Kidneys

Credit: iStock

World Mosquito Day, observed on August 20, raises awareness about mosquito-borne diseases such as dengue, malaria, Zika, yellow fever, and chikungunya and the health risks they pose.

Among these diseases, dengue remains a major public health concern, affecting people across regions worldwide throughout the year.

Dengue Cases: The Latest Numbers

  • Global: More than 1.5 million dengue cases and over 500 dengue-related deaths have been reported globally since the beginning of 2026, as of July 31.
  • Americas: 1,373,756 cases had been reported as of epidemiological week 26, updated July 23. Of these, 28.9% were laboratory-confirmed, according to WHO PAHO.
  • South-East Asia: WHO SEARO bulletins published in June and July reported dengue in Bangladesh, Bhutan, India, Maldives, Myanmar, Nepal, Sri Lanka, Thailand, and Timor-Leste since July 2025.
  • India: 22,938 cases had been reported in 2026 as of June. June recorded 6,625 cases, up from 3,747 in May — a 77% increase.

Also read: India’s First Approved Dengue Vaccine: Takeda’s QDENGA Protects Against All Four Virus Serotypes

Why Can Dengue Affect the Kidneys?

Dengue is typically associated with high fever, joint pain, and low platelet counts. However, severe dengue can affect the kidneys and lead to acute kidney injury (AKI).

Speaking to HealthandMe, nephrologists said kidney problems may not always cause symptoms early on, making monitoring particularly important in severe dengue.

Dr. Anupam Roy, Additional Director - Nephrology and Kidney Transplant, Aakash Healthcare Multi-Speciality Hospital, Dwarka, said that recovering from dengue requires careful fluid management, particularly in severe cases.

It is because the kidneys regulate fluids and electrolytes, and changes in circulation caused by dengue can temporarily disrupt their function.

Fever, vomiting, and poor fluid intake can cause dehydration, while severe dengue can cause plasma leakage. Both too little and too much fluid can create problems, making medical supervision important. In hospital, healthcare professionals monitor urine output and signs of dehydration, particularly in patients with complications or underlying health conditions.

After the acute phase, patients should gradually resume eating and drinking according to medical advice. Excessive fluid intake and self-medication should be avoided, particularly when medicines could place additional stress on the kidneys.

“So, it is the quantity issue that must be tackled,” Dr. Roy said.

Signs of Kidney Problems

Read More: Dengue Serotypes Shifting In Young Adults: How India's Indigenous Vaccine Could Help Prevent Severe Disease

According to Dr. Manoj Arora, Consultant Nephrologist, NephroPlus, a network of dialysis centers, warning signs include:

  • Decreased urination
  • Swelling of the face or legs
  • Dark or foamy urine
  • Increased blood pressure
  • Unusual tiredness
  • Nausea
  • Breathing problems
Tea-colored urine may be concerning for rhabdomyolysis, in which muscle breakdown releases substances that can injure the kidneys.

Some symptoms can overlap with severe dengue, including continuous vomiting, severe stomach pain, and bleeding.

Who Is at Higher Risk?

Kidney injury is more likely in people with severe dengue or shock. Older people and those with diabetes, hypertension, obesity, or existing kidney problems may also face higher risk.

Seek medical attention for a drastic reduction in urine, new swelling, blood in the urine, worsening breathlessness, confusion, or continuous vomiting.

In hospitalized patients, monitoring is important when creatinine rises, electrolyte levels fluctuate — particularly potassium — or urine output continues to change.

How Can Kidney Damage Be Prevented?

Early recognition and appropriate management are key. Doctors may monitor:

  • Fluid balance
  • Urine output
  • Kidney function
  • Electrolyte levels
  • Potentially harmful medications

Do not self-medicate or increase fluid intake without medical advice, particularly during severe dengue.

How to Reduce Your Risk of Dengue

Reducing mosquito exposure and preventing mosquito breeding can help lower the risk of dengue.

  • Eliminate stagnant water
  • Use mosquito repellents
  • Use bed nets
  • Keep mosquitoes out
  • Wear protective clothing
  • Check your surroundings regularly.

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