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?

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.

Climate change caused a 10 per cent global increase in Salmonella antibiotic resistance genes between 1940 and 2023, according to the first-of-its-kind study published in The Lancet Planetary Health journal today.

Antimicrobial resistance (AMR) is mainly driven by the overuse and misuse of antibiotics, which allows resistant bacteria to survive and spread.

However, rising temperatures and changing rainfall patterns can influence how bacteria survive, mutate, and spread, potentially increasing the exchange of antibiotic resistance genes.

“The accumulated evidence suggests that climate change is an accelerating force behind the global spread of antimicrobial resistance,” the study authors wrote in the paper.

What Are The Findings?

The study provides supporting evidence that AMR doesn’t just increase steadily as temperatures rise, but that the number of resistance genes changes over time in a more complicated way, depending on both temperature and rainfall. This suggests that environmental changes can speed up how bacteria adapt to antibiotics.

“These findings reinforce the idea that climate change alters microbial ecological stability and accelerates resistance evolution across human, animal, and environmental reservoirs," said the global researchers.

How Was The Study Conducted?

The current study analyzed the genomes of more than 480,000 Salmonella samples from 139 countries, collected between 1940 and 2023, and compared levels of antibiotic resistance genes with changes in average temperature and rainfall over time.

Of the total, 82 per cent of countries saw increases in antibiotic resistance genes in Salmonella, with the strongest climate-associated increases occurring in the Middle East and North Africa, followed by South Asia and Sub-Saharan Africa.

While the study shows a link between climate change and antibiotic resistance genes in Salmonella, it does not prove that climate change directly causes the increase.

The study also used a model to predict the change in antibiotic resistance genes in Salmonella by 2100 under different climate emissions scenarios.

The model suggests that if countries meet low-emission climate targets and strengthen efforts to use antibiotics responsibly, levels of resistance genes could be 24% lower than under the highest-emission scenario. However, they caution that these projections, as with all models, involve uncertainty.

The researchers stressed the need to consider climate change when monitoring and addressing AMR. They add that stronger climate action, alongside responsible antibiotic use and improved disease surveillance across humans, animals, and the environment, will be important in limiting the future spread of AMR.

What Is Salmonella?

As per the US Food and Drug Administration (FDA), Salmonella is a group of bacteria that can cause gastrointestinal illness and fever called salmonellosis. It can be spread by food handlers who do not wash their hands and/or the surfaces and tools they use between food preparation steps. It can also happen when people consume uncooked and raw food. Salmonella can also spread from animals to people.

Common symptoms of Salmonella include

• diarrhea,
• fever,
• stomach cramps 6 hours to 6 days after being exposed to the bacteria.

Children younger than 5, adults 65 and older, and people with weakened immune systems are more likely to have severe illness.

Indian summers are not just uncomfortable; they are becoming increasingly dangerous. With temperatures frequently crossing 45–48°C, heatwaves are putting excess stress on the human body, which hitherto had not experienced this level of heat strain. Now, add smoking to this already hostile environment and, like adding fuel to a fire, two harmful components combine to multiply the damage. Dr Shubham Garg, Director of Surgical Oncology, Dharamshila Narayana Superspeciality Hospital, Delhi, spoke about the risks of stepping out to grab a smoke during extreme heatwaves.

Smoking during heatwaves doesn’t just worsen existing risks; it accelerates dehydration, strains the heart, damages the lungs, and pushes the body closer to heat exhaustion or heatstroke. Here’s why lighting up in extreme heat is far more dangerous than most people realise.

Heatwaves Already Stress the Body—Smoking Adds Fuel to the Fire

When temperatures soar, your body works overtime to cool itself. A host of processes happen to aid in this—your blood vessels dilate, there could be an increase in heart rate, and sweating intensifies in order to regulate body temperature. When you smoke, it interferes with these very natural defense mechanisms of your body.

Nicotine results in vasoconstriction—narrowing of blood vessels—which makes it very difficult for the body to release heat trapped inside. The carbon monoxide from cigarettes reduces oxygen delivery to tissues. The result? Less oxygen reaches your organs, which are, in fact, working harder in the extreme heat. This is a perilous combination that can affect the body in many ways.

Dehydration Happens Faster Than You Think

A heatwave leads to sweating and, consequently, loss of fluids and electrolytes. And when you go for smoking a cigarette, it leads to fluid loss and delayed hydration. Nicotine acts as a mild diuretic, which contributes to increased fluid loss. Smoking also suppresses thirst signals, thus delaying hydration.

Collectively these factors raise the risk of severe dehydration, which can trigger dizziness, muscle cramps, low blood pressure, and confusion—all of which are early signs of heat exhaustion. Many smokers ignore these signs or dismiss them altogether.

A Deadly Mix for the Heart

Cardiovascular strain can happen independently through either smoking or heat. That in itself is a threat one should keep an eye out for. However, when combined, they pose a compelling risk of:

1. Sudden spikes or drops in blood pressure
2. Irregular heart rhythms
3. Heat-induced cardiac events

During extremely hot weather conditions, especially during a heatwave, the heart has to exert more effort to maintain circulation and cooling in the body. Smoking elevates heart rate and blood pressure further while also thickening the blood and increasing the risk of heart attacks and strokes, especially in people with pre-existing diabetes, hypertension, or heart disease.

Lungs Struggle More in Hot, Polluted Air

Hot weather is bad for air pollution levels too, as it traps smoke, dust, and harmful gases close to the ground. When one smokes in these conditions, it severely compromises lung function:

1. Airways become inflamed and constricted
2. Oxygen exchange efficiency drops
3. Symptoms like breathlessness, coughing, and chest tightness worsen

For people with asthma, COPD, or other respiratory conditions, smoking during a heatwave is likely to trigger severe flare-ups and emergency hospital visits.

Heat + Smoking Accelerates Ageing and Skin Damage

Extreme heat is damaging not just for the heart but for the skin as well. The skin becomes dehydrated, and collagen breaks down. Smoking compounds this damage by reducing blood flow and oxygen supply to the skin.

The result:

1. Faster wrinkles and sagging skin
2. Increased pigmentation and dullness
3. Delayed healing of rashes, infections, and sun damage

In short, smoking during summer doesn’t just harm internal organs; it visibly accelerates the ageing process.

Higher Risk of Heat Exhaustion and Heatstroke

Smoking reduces the body’s ability to regulate temperature effectively. This makes smokers more vulnerable to heat exhaustion (fatigue, nausea, headache, dizziness) and heatstroke (confusion, collapse, organ failure).

Heatstroke is a medical emergency and can be fatal if not treated promptly. Smokers often misread early warning signs as ‘normal summer weakness,' thus delaying care.

Why Cutting Down Isn’t Enough

Many smokers try to “reduce” smoking during summer. While any reduction helps, heatwaves are one of the worst times to smoke at all. Even a few cigarettes can significantly increase physiological stress when temperatures are extreme.

Smoking during heatwaves is not just bad—it’s dangerously synergistic. If there ever is a time to quit, or at least pause, this should be it. Because in peak summer, smoking doesn’t just harm you slowly. It fast-tracks damage, turning heat into a silent but serious health threat. In extreme heat, choosing not to smoke isn’t just a lifestyle choice—it’s a life-saving one.

When the heart stops functioning, time doesn’t stop with it. In cases of cardiac arrest, time serves as one of the most decisive factors between survival and irreversible loss. Within a couple of seconds, the body starts losing its oxygen supply. In a few minutes, the brain starts to suffer damage. And with each passing minute without intervention, the chances of survival reduce significantly.

This severe reality is at the centre of what Dr Ankit Desai, Paediatric Anaesthetist and Founder & Director of Children’s Anaesthesia Services, explains as “a race against biological shutdown — one where the bystander is the only lifeline”.

The silent collapse: what happens in cardiac arrest

Several people have the misconception that cardiac arrest is similar to a heart attack, but they are very different. A heart attack is a circulatory issue where the heart might still be beating. However, in cases of cardiac arrest, there is an electrical failure, and the heart suddenly stops pumping blood effectively.

Whenever this occurs, blood flow to the brain and other vital organs ceases immediately. The oxygen reserves in the brain are extremely limited and typically last for about 4 to 6 minutes before any permanent injury occurs.

This is where the concept of time sensitivity becomes more important. For every passing minute without CPR or defibrillation, the chances of survival drop by approximately 7–10%. By the time 10 minutes have elapsed without intervention, survival is extremely unlikely in most cases.

“The tragedy is not just the cardiac arrest itself,” explains Dr Desai, “but the silence that follows — when no one knows what to do or hesitates too long to act.”

The brain’s narrow window of survival

The brain is the first organ to be affected during cardiac arrest. Neurons are highly sensitive to oxygen deprivation. Brain cells start to malfunction within 3 minutes. By 5 minutes, the damage starts becoming increasingly severe. Beyond 10 minutes, the chances of meaningful recovery drastically reduce. This is why immediate CPR is not just a supportive measure but a bridge that keeps oxygen flowing artificially until a normal rhythm can be restored.

Chest compressions manually pump blood to the brain and heart, delaying cell death.

Why bystander action matters more than ambulance time

Emergency medical services, even in well-equipped systems, often take several minutes to reach a patient. In urban areas, response times may be shorter, but they are rarely instantaneous. In cardiac arrest, those minutes matter more than any hospital intervention.

Dr Desai emphasises that “the first responder is almost always not a doctor — it is a family member, a colleague, or a nearby stranger”.

This makes bystander CPR the most critical determinant of survival. Studies consistently show that when CPR is initiated immediately, survival rates can double or even triple compared to cases where no bystander action is taken.

Yet fear, hesitation, and lack of training remain major barriers. Many people worry about performing CPR incorrectly, causing harm, or being held legally responsible. In reality, doing nothing is far more dangerous than taking imperfect action.

The Chain of Survival: breaking down the timeline

Medical professionals often refer to this situation as the “Chain of Survival”, which includes early detection of cardiac arrest, immediate CPR, rapid defibrillation (AED use), advanced medical care, and post-resuscitation support. Every link in this chain is highly time-sensitive. Any delay in one step weakens the entire outcome. The strongest determinant, however, remains the second step — early CPR.

Automated External Defibrillators (AEDs), if available, can help restore a normal heart rhythm if used quickly. But again, their effectiveness decreases sharply with delay. The combination of CPR and early defibrillation within the first few minutes offers the best chance of survival.

Why awareness changes everything

The key difference between life and death is less about complexity and more about readiness.

Awareness training helps transform bystanders into responders. A person who knows how to identify cardiac arrest — unresponsiveness, absence of breathing, sudden collapse — is far more likely to act immediately rather than wait.

Dr Desai highlights a critical cultural gap: “We often associate medical emergencies with hospitals. But cardiac arrest begins in living rooms, offices, gyms, and streets. The response must begin there, too.”

Basic CPR training takes less than an hour to learn, but can influence outcomes for decades. Schools, workplaces, and community programmes play a vital role in normalising this skill.

Overcoming hesitation: the psychological barrier

One aspect of cardiac arrest that often gets overlooked is human hesitation. Bystanders often freeze due to shock and uncertainty. Some assume that someone else will step in. Others underestimate the severity of the situation.

Public awareness campaigns help highlight the simplicity of CPR, which helps overcome this barrier. Hands-only CPR focuses on continuous chest compressions without mouth-to-mouth breathing, making intervention much easier and more accessible. The message is simple: push hard, push fast, and don’t stop until help arrives.

A shift from reaction to preparedness

Cardiac arrest survival is not just a medical issue, but also one of public preparedness. The Chain of Survival starts long before the emergency happens. It starts with education, confidence, and awareness.

Dr Desai states that “if more people understood how little time they truly have, more lives would be saved not by hospitals, but by ordinary people doing extraordinary things in the first five minutes”.

Conclusion: time is the real patient

In cardiac arrest, the patient is not just the person who collapses — it is time itself. Every second lost reduces the chance of recovery. Every trained bystander becomes a potential lifesaver. The science is clear, the timeline is unforgiving, and the solution is remarkably simple: act immediately, compress the chest, and keep blood flowing until professional help arrives.