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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Healthy Outside, Struggling Inside: The Rise of ‘Invisible Fertility Issues’

Updated Apr 23, 2026 | 11:00 PM IST

SummaryUnderstanding that fertility is influenced by both visible and invisible factors is the first step towards addressing the issue effectively.
Invisible infertility

Seemingly healthy people can also face fertility problems due to underlying health problems. (Photo credit: iStock)

In today’s fast-paced, wellness-driven world, looking fit does not always translate to being reproductively healthy. Currently, even fit and active individuals are facing fertility challenges due to hidden hormonal and metabolic imbalances. Hence, it is necessary to focus on reproductive health. Dr. Meenu Handa, Director of Fertility & Head Academic of Reproductive Medicine, Motherhood Hospitals, Gurgaon, decoded the link and listed some of the common fertility issues that most people overlook.

Now, a large number of people are opting for various activities such as yoga, Zumba, Pilates, the gym, and kickboxing to stay fit. Those who are health-conscious are also maintaining an optimum weight with a proper diet. These habits, in turn, can help to ensure good fertility. Shockingly, many people who are perfectly fit and fine on the outside may also struggle with fertility problems. Yes, that is right! This is also a common occurrence nowadays. Couples are panicking as they seem to adhere to a well-balanced lifestyle but still fail to conceive. So, this can be referred to as “invisible fertility issues," where underlying hormonal or metabolic imbalances silently affect reproductive health.

Decoding invisible fertility issues

Dr Handa said that many men and women who exercise regularly may suffer from issues such as hormone imbalance, fluctuating insulin levels, poor thyroid function, and compromised reproductive organ health. Conditions like polycystic ovary syndrome (PCOS), thyroid disorders, insulin resistance, and even chronic stress can exist without obvious physical signs and can take a toll on fertility. The expert also shared some of the common hidden infertility issues.

Even couples who are physically fit today often deal with high mental stress due to demanding jobs and poor work-life balance. This ongoing stress can quietly disturb hormonal balance in the body. Increased cortisol levels may affect ovulation in women and sperm production in men and, over time, can impact egg and sperm quality—making natural conception more difficult. That is why managing stress is just as important as staying physically fit when planning a pregnancy.

Women may have issues like poor ovulation, compromised egg quality, or hormonal imbalance, even if their menses tend to be regular. In some cases, even subtle symptoms like fatigue, acne, hair fall, or mood swings may be overlooked but can signal deeper hormonal concerns. Men can struggle with low sperm count, which can affect their fertility. Even insufficient sleep, excessive exercise, or extreme dieting can increase the chances of hormonal imbalance and fertility issues. It is necessary to consult an expert and seek timely help. Pollution and lifestyle stress also contribute to the trend.

Couples should not just plan a pregnancy because they are fit and exercise daily. Pregnancy should not rely only on outward fitness as a sign of reproductive health. Regular health check-ups, including hormone tests and fertility assessments, can help identify hidden issues early.

Follow these tips

  1. Couples should eat a well-balanced diet, exercise daily, stay stress-free by practicing yoga and meditation, and get enough rest.
  2. It is also imperative to maintain blood pressure and blood sugar levels within the recommended range, include healthy fats and proteins in the diet, avoid overtraining, and manage stress through relaxation techniques like yoga or meditation, which can support hormonal balance.
  3. If a couple is unable to conceive even after 6–12 months of trying (depending on age), a detailed fertility evaluation is recommended.
  4. Seeking timely medical advice is equally important if conception is delayed.
  5. Couples who find it challenging to conceive may be advised to use ARTs, such as in vitro fertilisation (IVF).

So, awareness, balanced lifestyle choices, and timely medical support can make a huge difference in improving fertility outcomes.

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Can Heatwave Make You More Prone To Stroke?

Updated Apr 23, 2026 | 07:00 PM IST

SummaryAccording to doctors, people dealing with comorbidities like heart disease and diabetes must avoid stepping out amid a heatwave.
Stroke

Stroke is a medical emergency which can lead to death if not addressed immediately. (Photo credit: iStock)

A heatwave is getting worse with each passing day, and with it come dehydration, stomach flu, and sometimes even mood swings. But little do people realise that the risks associated with a heatwave could be much worse - it turns out that exposure to extreme heat could also give you a stroke. Dr Deep Das, Consultant - Neurology, CK Birla Hospitals, CMRI, in an interview with Health and Me, decoded the link between heatwaves and the risk of stroke.

How does a heatwave affect stroke risk?

Dr Das said that in very high temperatures, the body does not always cope in predictable ways. The brain is particularly sensitive to these shifts. One of the concerns is stroke. In the heat, people tend to lose fluids without realising how much. Blood volume drops, and circulation is affected. In some cases, the blood becomes more prone to clotting. At the same time, blood pressure can fluctuate. This combination increases the chances of a disruption in blood flow to the brain.

Can extreme heat give you a seizure?

Seizures are another risk, especially in those who already have epilepsy. Even when the condition has been stable, heat can unsettle things. Dehydration and changes in electrolyte balance make the brain more reactive than usual. A person who has been well-controlled for months may still have an episode during a prolonged heatwave. What makes this difficult is that these changes are not always gradual. Symptoms can appear suddenly.

What are the symptoms of a stroke?

A stroke refers to a potentially fatal medical emergency. It can be sudden or gradual, and it is characterised by a blockage in blood circulation to the brain. It can result in rapidly dying brain cells and requires immediate medical attention. The symptoms of stroke can be identified as FAST:

  1. Face: Face drooping on either side
  2. Arms: Weakness in the arms or inability to move the arms
  3. Speech: Slurred speech
  4. Time: Time is an important factor; immediate action can be life-saving for stroke patients

Apart from this, other symptoms of a stroke are:

  1. Severe, unusual headaches
  2. Confusion
  3. Loss of consciousness
  4. Dizziness
  5. Loss of balance
  6. Inability to see clearly from one or both eyes

How to dodge a heatwave-related stroke?

In this weather, small precautions matter more than they seem. Some of the best ways to dodge a stroke amid a heatwave are:

  1. Drinking water regularly helps, even before you feel thirsty
  2. Staying indoors during peak afternoon hours reduces strain on the body
  3. Living spaces need some form of airflow, even if it is basic ventilation

It also helps to keep an eye on people who may not notice these changes early—older adults, those living alone, or anyone with an existing medical condition.

Should you be worried?

Some people are more prone to stroke risk than others. Therefore, it is important to be aware of the risk factors, especially during a heatwave. If you are dealing with any of the following comorbidities, think twice before stepping out amid a worsening heatwave:

  1. Hypertension
  2. Diabetes
  3. Irregular heartbeat
  4. Sleep apnoea
  5. High cholesterol

Furthermore, people who are 65 years and above must avoid stepping out from 12 noon to 4pm. Even people who have a family history of stroke must not step out during these hours.

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Annual vs Biennial Mammograms For Breast Cancer: What Experts Say

Updated Apr 22, 2026 | 10:00 PM IST

SummaryA mammogram is a low-dose X-ray that captures detailed images of breast tissue, capable of identifying cancers before any physical symptoms appear.
Annual vs Biennial Mammograms For Breast Cancer: What Experts Say

Credit: iStock

Breast cancer remains one of the most common and fatal cancers among women worldwide, and early detection is proven to play a crucial role in improving outcomes. While mammography remains the most effective screening tool, knowing when to start and how often to get screened can be confusing.

The changing medical guidelines, as with the new screening guidelines from the American College of Physicians (ACP), can also leave women confused about when to start mammograms and how often to repeat them. HealthandMe spoke to experts to understand the correct timing.

So, What Do The ACP Guidelines Say?

The new guidance statement developed by ACP's Clinical Guidelines Committee urged mammography screening once every two years in asymptomatic, average-risk adult females, instead of the annual recommendation.

The ACP guidelines further state that all average-risk females ages 50 to 74 must undergo biennial mammography. It added that women aged 75 years or older with asymptomatic and average-risk can also discuss stopping routine screening with their doctor.

In sharp contrast, the United States Preventive Services Task Force (USPSTF) urges starting annual screening at age 40 to save lives.

What You Should Follow

“Some cancer societies like the American Cancer Society say biennial, while NCCN says annually. We prefer annually starting at age 40 till the woman is in good health, as biennial screening may delay early diagnosis in some cases,” Dr. Ashwani Kumar Sharma, Vice Chairman - Manipal Comprehensive Cancer Centre and Onco Robotic Surgeries, Manipal Hospitals, Gurugram, told HealthandMe.

NCCN, or the National Comprehensive Cancer Network, is an alliance of 34 cancer centers in the US.

Dr. Sharma added that a practical and balanced approach would be to do biennial mammography from 40 to 50 years of age and annual mammography after 50 years of age for maximum benefit.

What Are Mammograms?

A mammogram is a low-dose X-ray that captures detailed images of breast tissue, capable of identifying cancers before any physical symptoms appear.

In women with a BRCA1 or BRCA2 gene mutation who are referred to as "high risk" or with a history of radiation to the chest between ages 10 and 30, screening may start as early as age 30 and include annual breast MRIs alongside mammograms.

Mammograms: What Do India’s Guidelines Say?

Breast cancer in India is usually diagnosed at an advanced stage due to poor health awareness. But of late, there has been an increase in awareness, and more and more women are reporting in their earlier stages with a breast lump.

“Sometimes even this is too late. Breast cancer screening would help us diagnose this disease at an even earlier stage to help increase the chances of a cure from this deadly but treatable disease with the help of simple tests,” Dr Abhijit Kotabagi, Senior Consultant, Department of Surgical Oncology, Yatharth Hospital, Noida, told HealthandMe.

“I would endorse screening and women’s health awareness in our Indian population for women above 40 years after discussion of the pros and cons of screening with a clinician,” he added.

The Indian Council of Medical Research (ICMR) and other health organizations recommend the following guidelines:

1. Women Aged 30-40 Years

  • Clinical Breast Examination (CBE) every 1-3 years by a doctor.
  • Self-Breast Examination (SBE) every month to check for lumps or changes.

2. Women Aged 40-50 Years

  • Annual Clinical Breast Examination (CBE).
  • Mammogram (X-ray of the breast) every 2 years if advised by a doctor.

3. Women Above 50 Years

  • Mammogram every 2 years (or as recommended by a doctor).
  • Continue monthly self-exams and yearly clinical exams.

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