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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IBS Is Not Just A Gut Problem: Lancet Review Explains The Gut-Brain Connection

Updated Nov 2, 2026 | 09:09 AM IST

SummaryA recent review in Lancet focuses on how irritable bowel syndrome is affected by how the brain processes pain and other sensations.
IBS Is Not Just A Gut Problem: Lancet Review Explains The Gut-Brain Connection

Credit: AI

Irritable bowel syndrome (IBS) is often characterised by digestive symptoms like abdominal pain, bloating, constipation and diarrhoea. However, the condition involves more than the digestive system.

A new review published in The Lancet explains how interactions between the gut and brain, changes in the gut microbiome, immune activity and the body's response to pain can contribute to the development of symptoms.

The review, titled Irritable bowel syndrome and related disorders of gut-brain interaction, brings focuses on biological and psychological evidence behind IBS. Researchers describe it as a disorder of gut-brain interaction, in which signals between the digestive system and the central nervous system affect gut function.

The authors also discuss chronic constipation and functional diarrhoea, which belong to the bigger group of disorders related to gut-brain interaction. These conditions may affect an estimated 20% of the global population.

What Is The Gut-Brain Connection In IBS?

Also read: Olympian Ciara Mageean Dies At 34 After Bowel Cancer Battle: Warning Signs In Young Adults

The gut and brain communicate continuously through a complex network that involves the central nervous system, autonomic nervous system, enteric nervous system and hypothalamic-pituitary-adrenal (HPA) axis.

The brain can influence intestinal movement, secretion and sensitivity, while signals from the gut can affect how the brain processes pain and other sensations.

In people with IBS, this communication may become disrupted. The result can be changes in bowel movements, more sensitivity to normal digestive processes and abdominal discomfort.

The authors said, “These central and peripheral mechanisms can act in an integrated way to cause IBS symptoms, via the gut-brain axis.”

For instance, a person with IBS may experience pain or bloating even when the amount of gas or intestinal movement would not cause discomfort in someone without the condition. This is due to a condition called visceral hypersensitivity, in which the nerves supplying the digestive organs become unusually sensitive to internal sensations.

The review explains that changes in both peripheral mechanisms within the gut and central mechanisms involving the brain can contribute to symptoms.

Gut Bacteria And Inflammation May Contribute To IBS

Also read: Can Coffee Trigger Irritable Bowel Syndrome?

The gut microbiome, which consists of microorganisms living in the digestive tract, is another important part of the gut-brain connection.

Changes in the composition and activity of gut bacteria may impact intestinal function, immune responses and communication with the nervous system. The review identifies the following:

  • Gut infections: Gastrointestinal infections can trigger IBS symptoms in some people, even after the initial infection has subsided.
  • Altered gut microbiome: Changes in intestinal bacteria may affect digestion, immune activity and gut function.
  • Increased intestinal permeability: Changes in the intestinal barrier may allow substances to pass through more easily, potentially contributing to immune activation.
  • Low-grade inflammation: Mild inflammation in the intestinal lining and changes in immune function may contribute to symptoms.
  • Abnormal gut movement: Changes in gastrointestinal motility can cause food and waste to move through the digestive tract too quickly or too slowly.
  • Visceral hypersensitivity: Increased sensitivity in the gut can make normal digestive processes feel painful.

Mental Health And IBS

Psychological health is another component of the gut-brain axis. Stress, anxiety and other psychological difficulties can influence how the brain processes pain and communicates with the digestive system.

The HPA axis, which helps regulate the body's response to stress, plays a role in this process . Changes in stress levels can affect gut movement, secretion and sensitivity.

Currently, there is no single biomarker that can diagnose IBS. Doctors assess symptoms, medical history and clinical findings, while using tests to rule out other conditions.

The review highlights that some underlying mechanisms can already be measured through approved tests and questionnaires. These include abnormal bile acid metabolism, accelerated movement of contents through the colon and psychological conditions.

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Patients Treated By Female Doctors Have Lower Risk Of Death, Study Finds

Updated Nov 2, 2026 | 01:00 AM IST

SummaryA study in published in JAMA Network Open observed that patients had 12.3% mortality rate when treated by female physicians, compared to 13.7% when treated by male physicians.
Patients Treated By Female Doctors Have Lower Risk Of Death, Study Finds

Credit: iStock

Does a patient’s chances of serious outcomes differ if they are treated by a female doctor? A recent study looks into this hypothesis to ascertain the difference between chances of a patient dying under a male and a female doctor.

According to the study, hospitalised patients treated by female doctors have a lower risk of dying within 30 days. They are also less likely to be re-hospitalised than those treated by male doctors. The study is published in JAMA Network Open.

"Past research has largely focused on surgical patients and the admitting physician only. Our findings add to the growing body of research examining the relationship between physician sex and patient outcomes, broadening the evidence beyond surgical care to a wider range of medical conditions and other physicians," says Dr. Angela Jerath, an ICES scientist, and Associate Professor, Department of Anesthesiology & Pain Medicine at the University of Toronto's Temerty Faculty of Medicine.

After analysing the health records of 958,150 adults admitted to hospitals in Ontario, Canada, between 2008 and 2022, researchers found that the 30-day mortality rate was 12.3% among patients treated by female physicians, compared to 13.7% among those treated by male physicians.

The findings also show a small difference in hospital readmissions. The 30-day readmission rate was 18.6% for patients treated by female doctors and 18.9% for those treated by male doctors.

The researchers examined outcomes across seven common medical conditions, including heart attacks, pneumonia and other acute illnesses.

They also considered the number of hospital days during which patients received care from female doctors, recognising that several doctors may be involved in a patient's treatment during an admission.

Patients Treated By Female Doctors Are Less Likely To Die In A 30-Day Period

Also read: Manosphere Is A Public Health Concern: Lancet Report Says Online Misogyny Harms Men's Mental Health

After accounting for patient, physician and hospital characteristics, treatment by a female physician was linked with 12% lower adjusted odds of death within 30 days compared to treatment by a male physician.

The researchers also found that for every 10% increase in the proportion of hospital days managed by female physicians, the adjusted odds of 30-day mortality decreased by 7%. This was observed for most medical conditions that were studied. Atrial fibrillation was the only exception.

The difference in mortality was also seen at longer follow-up periods. Patients treated by female physicians had lower mortality at 90 days and one year.

The findings were observed among both male and female patients. Female patients treated by female physicians had the lowest adjusted 30-day mortality rate in the analysis.

Why Patients May Have Better Outcomes With Female Doctors?

The study did not establish why patients treated by female physicians experienced better outcomes. However, the researchers discussed possible differences in clinical practice and communication.

Female physicians may be more likely to engage in patient-focused communication, spend more time with patients, follow clinical guidelines and involve colleagues in decision-making.

These practices could influence how symptoms are studied, treatment decisions are made and coordinated during hospitalisation.

"The goal is not to favour one group of physicians over another but to identify practices and behaviours that may help improve care across the health system," says Jerath.

"An important strength of this study is that, unlike surgical care, patients admitted to hospital for medical conditions are generally assigned physicians based on rotating schedules rather than patient or referring physician preferences, helping to minimize referral bias."

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Retatrutide Vs Ozempic: Eli Lilly’s Experimental Drug Delivers More Than Double The Weight Loss

Updated Nov 1, 2026 | 11:00 PM IST

SummaryIn a recent head-to-head trial, Eli Lilly's 'Godzilla' drug retatrutide resulted in an average of 20.9% weight loss over 80 weeks compared to Ozempic's weight loss of 9.4%
Retatrutide Vs Ozempic: Eli Lilly’s Experimental Drug Delivers More Than Double The Weight Loss

Credit: AI

Eli Lilly's experimental weight-loss drug retatrutide, being referred to as ‘Godzilla’, continues to outperform its rivals like Ozempic.

According to a recent head-to-head Phase 3 clinical trial involving adults with type 2 diabetes, it delivered more than twice the average weight loss achieved with Ozempic.

Ozempic Vs Retatrutide

Participants who took the highest dose of retatrutide lost an average of 20.9% of their body weight over 80 weeks, compared to 9.4% among those receiving Ozempic's highest approved dose for type 2 diabetes.

The trial, called TRANSCEND-T2D-2, involved more than 1,000 adults with type 2 diabetes. It compared once-weekly injections of retatrutide at doses of 9 mg and 12 mg with semaglutide, the active ingredient in Ozempic, at 2 mg.

At the end of 80 weeks, participants taking retatrutide 9 mg lost an average of 44.3 pounds (20.1 kg), while those receiving the 12 mg dose lost 47.4 pounds (21.5 kg). The Ozempic group lost an average of 20.9 pounds (9.5 kg).

The findings mark the first Phase 3 head-to-head comparison of retatrutide with another medicine in this class.

Also read: ‘Godzilla’ Drug Retatrutide Reverses Sleep Apnea In 1 In 4 Diabetes Patients

Retatrutide Also Improved Blood Sugar

The trial found that retatrutide also resulted in produced greater reductions in HbA1c, a measure of average blood glucose over approximately three months.

At 80 weeks, participants taking either dose of retatrutide recorded an average HbA1c reduction of 2.2%, compared to 1.8 % among those receiving Ozempic.

The experimental drug also resulted in greater improvements in cardiovascular risk factors like non-HDL cholesterol, triglycerides and systolic blood pressure.

Also read: Could GLP-1 Drugs Help Prevent Rupture Of Abdominal Aortic Aneurysm? Study Finds 46% Reduction In Risk

Side Effects Of Retatrutide

The most commonly reported side effects of retatrutide were gastrointestinal symptoms like diarrhoea, nausea, constipation, vomiting and indigestion.

Diarrhoea was reported in 28.3% of participants receiving the 9 mg dose and 32.7% receiving 12 mg, compared to 26.4% in the Ozempic group. Nausea occurred in 21.2%, 23.8% and 21.3% of participants, respectively.

Researchers also reported a higher incidence of dysesthesia, an abnormal sensation that can include tingling, burning or skin sensitivity, among participants taking retatrutide.

Treatment discontinuation because of side effects occurred in 4.8% of the 9 mg group and 7.9% of the 12 mg group, compared to 2.7% of the Ozempic group.

More About Retatrutide

Retatrutide is a once-weekly injectable drug that targets three hormone receptors involved in regulating appetite, blood sugar and metabolism. They are GLP-1, GIP and glucagon.

GLP-1 helps regulate appetite and blood sugar while slowing the process of stomach emptying. GIP also plays a role in glucose regulation and insulin release. Glucagon is involved in controlling blood glucose and energy metabolism.

Ozempic, manufactured by Novo Nordisk, acts on the GLP-1 receptor. Eli Lilly's Mounjaro and Zepbound, which contain tirzepatide, target both GLP-1 and GIP receptors.

Retatrutide remains an investigational drug and has not been approved by the US Food and Drug Administration (FDA) or other regulatory authorities.

Eli Lilly plans to submit the drug for FDA approval in early 2027. The company said detailed results from the trial would be presented at a future medical meeting and published in a peer-reviewed journal.

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