Sleep changes as we age. When we were kids, we needed 10 to 12 hours of sleep, for teens it is eight to 10 and it decreases to seven to nine as we reach adulthood. But there is always a lack of urgency when it comes to sleep and young adults, many of whom prefer staying up and doing different activities. According to the Centre of Disease Control and Prevention, many national surveys show that about 37% of men, and 39% of people from the age of 45 to 64 reported not getting enough sleep.

Many people in America don't sleep the right amount. This means they either sleep too long or not long enough. But what happens to your body when you do not sleep enough? You just feel tired right? No, when you don't get this much sleep, your body can get stressed. This can make you more likely to get sick. A study published by the JAMA Network Open Sleep Trajectories and All-Cause Mortality Among Low-Income Adults showed that people who don't sleep the right amount have a higher chance of dying early. It's like your body needs that time to rest and fix itself. Without enough good sleep, things can start to go wrong. So, getting the right amount of sleep is super important for staying healthy.

How Was The Study Done?

Scientists wanted to see how sleep habits affect people's health over many years. They looked at almost 47,000 people who were between 40 and 79 years old. They asked them about their sleep habits when the study started, and then again, a few years later. The scientists wanted to see if people's sleep habits changed. They divided people into groups based on if they started with too much or too little sleep, and if their sleep changed over time. For example, some people started sleeping a lot but then started sleeping very little. This helped the scientists see how different sleep patterns affected people's health. They wanted to see the long-term effects of sleep.

The study found that people who had sleep habits that changed a lot had a higher risk of dying early. This means if you started sleeping too much and then switched to sleeping too little, or the other way around, you were more likely to die sooner. They also found that these people had a higher risk of heart problems. The risks were even higher for some groups of people, like white adults and people with higher incomes.

Sleep Deprivation And Its Effect On The Body

If you often doze off when you are sitting and reading, watching a movie, talking to someone, sitting quietly after lunch or even during a few minutes of traffic, you may be sleep deprived according to the National Heart, Lung, and Blood Institute. They explain how sleep deprivation can cause issues with learning, focusing and reacting to certain things. The symptoms of sleep deprivation in kids differ a little as they might be overly active and have trouble paying attention to certain things. If you are experiencing sleep issues, make sure to speak to a healthcare professional who will help you identify the issues and direct you towards the treatment or changes you must make. Here are some ways sleep helps your body.

Repairs Your Heart

Good sleep allows your heart and blood vessels to heal. This keeps them strong and healthy, reducing the risk of heart problems.

Controls Hunger

Sleep helps balance your hunger hormones, so you don't feel too hungry. This helps prevent eating too much and keeps your weight healthy.

Manages Blood Sugar

Proper sleep helps your body use insulin correctly. This lowers the chance of high blood sugar, which can lead to diabetes.

Supports Growth

Deep sleep releases growth hormones, helping kids and teens grow. It also repairs body tissues, which is important for everyone.

Boosts Immunity

When you sleep well, your body's defense system gets stronger. This helps you fight off germs and stay healthy.

Depression affects millions of people worldwide, but not everyone responds equally well to treatment. Now, researchers at the University of Sydney have identified a new subtype called “circadian depression,” which is linked to the body’s internal clock and may help explain why conventional antidepressants work less well for some people.

The subtype was identified in nearly a quarter of participants with severe, recurrent or persistent depression in an Australian study. Researchers say recognizing its characteristics could help clinicians identify patients who may benefit from different treatment approaches.

“Our research has identified circadian depression as a new subtype, affecting around a quarter of people in our study into those with severe, recurrent or persistent depression,” said Dr. Emiliana Tonini from the Brain and Mind Centre at the University of Sydney.

“Depression is not a uniform illness and understanding the characteristics of different subtypes mean that we can give people earlier access to treatments that will be most effective for them,” she added.

Circadian Depression: What Are The Key Symptoms?

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Circadian depression is linked to the body’s 24-hour internal clock, which regulates the sleep-wake cycle. Researchers identified several symptoms and characteristics associated with this subtype, including:

• A seasonal pattern of illness

• Sleeping longer during depressive episodes

• Waking up feeling very tired

• Being a night owl

To investigate the subtype, researchers analyzed clinical and genetic data from more than 10,000 people with depression who participated in the nationwide Australian Genetics of Depression Study.

Of these, 2,604 participants, or nearly 25%, were identified as having circadian depression.

The researchers also found that people with this subtype were more likely to experience depression earlier in life and had more severe symptoms, including mania and higher levels of suicidal thoughts.

In addition, these participants had a higher genetic risk for inflammatory and cardiovascular health problems, as well as major neurodevelopmental disorders, including attention-deficit/hyperactivity disorder (ADHD).

The findings, published in the British Journal of Psychiatry, offer insights into the genetic mechanisms associated with circadian depression and may help explain why conventional treatments, such as selective serotonin reuptake inhibitors (SSRIs), work less well for some people with this subtype.

How Does Circadian Depression Differ In Treatment Response?

Antidepressants such as SSRIs and serotonin-norepinephrine reuptake inhibitors (SNRIs) are commonly used to treat depression. However, the researchers reported that these medications were less effective and associated with more side effects in people with the circadian subtype.

Because circadian depression is linked to the body’s internal clock, treatments targeting circadian rhythms may be relevant for some patients. These include light therapy, melatonin and melatonin-targeted antidepressants.

“Because circadian depression is linked to people’s internal body clock, treatments targeting the circadian rhythm, such as light therapy and melatonin, may be much more relevant, and clinicians should reach for these much earlier in people with this presentation,” said Dr. Jacob Crouse, co-senior author of the study, from the Brain and Mind Centre.

“For those who find that antidepressants are not working for them, it is important to speak to your clinician for advice about your individual circumstances,” he added.

Professor Ian Hickie, co-director of the Brain and Mind Centre and a clinical psychiatrist, emphasized that failing to recognize circadian depression in young people could contribute to early treatment failures and more side effects.

“We really want young people to receive the most appropriate treatment early in their course of illness.

“Most young people will be offered SSRIs first up, but for at least a quarter there are better circadian-focused medical and behavioural options to help treat and manage their condition.”

The findings suggest that identifying circadian depression could help clinicians consider more tailored treatment approaches. However, the study does not establish that body-clock disruption causes depression or that every person identified with this subtype will respond better to circadian-focused treatments. Patients should consult their clinicians before making any changes to prescribed medication, the experts said.

After Dussehra festivities, Delhi woke up to an alarming AQI of 300, maybe even more in some parts of the city. On October 21, pollution curbs under GRAP-1 were implemented, which are brought in force when AQI ranges between 201 and 300.

As Delhi's air pollution increases, some people may experience uncommon symptoms like feeling unusually tired, sluggish or unable to concentrate. This is not just a coincidence. Even people without asthma or breathing difficulties can feel fatigue, especially during periods of high air pollution.

Fine particulate matter (PM2.5) can penetrate deep into the lungs and trigger inflammation and physiological stress. Its effects may extend beyond the respiratory system, affecting blood vessels health, cardiovascular function as well as sleep.

HeathandMe spoke to Dr Puneet Khanna, Chairman, Respiratory Medicine and Pulmonology, Manipal Hospital Dwarka, New Delhi, Dr. Puneet Gupta, HOD - Pulmonology, Intervention Pulmonology & Sleep Medicine, Yatharth Super Speciality Hospital, Noida Extension, and Dr Mrinal Sircar, Director, Respiratory and Sleep Medicine, Medanta, Noida, who explained why rising AQI can leave some people feeling exhausted, what can help and when chronic fatigue needs medical attention.

High AQI May Make You Feel Tired Even Without Breathing Problems

Poor air quality does not affect just the lungs. Dr Sircar explains that air pollution can cause symptoms even in people without a pre-existing respiratory condition.

According to Dr Khanna, exposure to PM2.5 can trigger inflammation and oxidative stress, increase the body's workload and affect sleep quality. These changes may contribute to tiredness, headaches, low energy and reduced concentration, even in people with otherwise healthy lungs.

“Exposure to polluted air may also affect sleep quality and increase the body's overall stress response, contributing to symptoms such as tiredness, reduced energy and difficulty concentrating,” he says.

Dr. Gupta delves deeper into the process of PM2.5's attack and how the body responds to it.

He explained, "Your immune system treats fine particles (PM2.5) as intruders and mounts a constant low-grade defence, which burns energy much like a mild infection. At the same time, irritated airways and gases like carbon monoxide can make oxygen delivery slightly less efficient. The most underrated cause is sleep: a dry throat, blocked nose, and mild night-time cough fragment your sleep, so you wake up unrefreshed without knowing why. Fatigue here doesn’t mean your lungs are weak. It means your body is working overtime quietly."

Also read: Sky Turns Orange In Indonesia: How Toxic Smog From Wildfires Can Impact Health

Can PM2.5 Affect The Heart And Blood Vessels Too?

PM2.5 particles are small enough to penetrate deep into the lungs. Some of its components can even enter the bloodstream. Exposure can trigger inflammatory and oxidative stress responses beyond the respiratory system.

Dr Khanna says, “These changes may reduce physical endurance, increase feelings of fatigue, and contribute to symptoms such as brain fog, lethargy, and reduced exercise tolerance, particularly during periods of severe air pollution.”

Dr. Gupta explained PM2.5 can create the same response from body as a common flu does. But the extent of these effects depends on pollution levels, duration of exposure and individual risk.

He said, "PM2.5 is small enough that it, or the inflammatory chemicals it triggers, can enter the bloodstream. Signalling molecules such as IL-6 and CRP then travel through the whole body and produce the same “wiped out” feeling you get with the flu."

He also said that particles also create oxidative stress, which damages mitochondria, the power plants of your cells. Blood vessels become stiffer, blood pressure can rise slightly, and the nervous system’s control of heart rhythm can be disturbed, which may feel like heaviness or palpitations. Inflammation can also reach the brain, causing fog and poor focus.

Also read: Delhi Smog: Can You Really Tackle Pollution Season With An N95 Mask And Air Purifier?

What Can Help?

According to the doctors, the key is to reduce exposure to polluted air. Practical steps include:

• Limit exertion: Avoid strenuous outdoor activity when pollution levels are high, especially during periods of severe pollution.
• Wear a well-fitting N95 respirator: It can reduce exposure to fine particles when outdoors.
• Improve indoor air quality: Keep windows closed when outdoor air quality is poor and use a suitably sized air purifier with a HEPA filter where feasible.
• Maintain basic health routines: Get adequate sleep, stay hydrated and eat regular meals.
• Check AQI levels: Use local air quality updates to plan outdoor activities.

Dr Khanna emphasises that these steps can help reduce exposure but cannot eliminate the effects of ongoing pollution. He also said that severe breathlessness, chest pain, fainting or sudden weakness requires urgent medical attention.

Does Pollution-Induced Fatigue Go Away When AQI Improves?

For many otherwise healthy people, symptoms can improve once air quality improves. Dr Khanna says recovery may occur within a few hours to several days, depending on pollution severity, exposure duration and individual health.

However, there is no fixed recovery timeline. People with underlying respiratory or cardiovascular conditions may take longer to recover, while persistent tiredness may point to another health problem.

Dr Sircar advises seeking medical advice if fatigue continues after air quality improves.

The doctors also advise that if fatigue is chronic, recurrent, worsening or interferes with daily activities, medical evaluation should be sought rather than simply attributing it to air pollution.

Dr Sircar also says that that a doctor may need to investigate other possible causes, including anaemia, thyroid disorders, sleep problems and cardiovascular conditions. Fatigue accompanied by a chronic cough, wheezing, breathlessness, chest problems or reduced exercise tolerance also needs intervention.

A single photograph of someone’s face might carry real clues about their health and how long they’re likely to live, at least according to new AI tools built by researchers at Mass General Brigham in Boston.

What the researchers built

The team trained a large AI foundation model called FAHR-Face, short for Foundation Artificial Intelligence for Health Recognition, on more than 40 million facial images.

From that base model, they built two specialised tools: FAHR-FaceAge, which estimates a person’s biological age from a single photo, and FAHR-FaceSurvival, fine-tuned on 34,389 photos of cancer patients to predict survival risk directly from facial appearance.

“I was pretty surprised to find out that we could pick up signs of mortality risk from just a facial photograph,” corresponding author is Dr. Raymond Mak, a radiation oncologist at Mass General Brigham Cancer Institute told CNN. The study is published in The Lancet Digital Health.

What the two tools actually look at

The two algorithms focus on entirely different parts of the face. “The age estimation algorithm is looking at the area around the temples, the area on the forehead, above the eyes and then what we call the nasolabial fold,” Mak said, while “the mortality risk prediction algorithm is looking at a totally different part of the face... the bridge of the nose and the area under the eyes.”

Also Read: ADHD Linked To 71% Higher Risk Of Death; Suicide And Injuries Among Top Concerns

The results

Among 122 cancer patients flagged by FAHR-FaceSurvival as high-risk, 52.5% died within 90 days, compared with about 2% of the 975 patients in the lowest-risk group. Separately, 21% of patients whose biological age came back more than 20 years older than their actual age died within 90 days, against about 6% of those whose biological age was at least 10 years younger than their chronological age.

The researchers also found that cosmetic changes, including surgery, Botox, or makeup, didn’t throw off the models’ performance, according to the Mass General Brigham release.

An eerie echo of ancient medicine

The facial regions both AI models rely on, the nose, temples, and the area around the eyes, closely match what the Greek physician Hippocrates described around 400 BC in his Book of Prognostics as signs of approaching death: “the nose sharp, the eyes sunken, the temples fallen in.”

Mak told CNN the algorithms had no exposure to Hippocrates’ text and were trained purely on photographs and outcomes data. “Hearing Hippocrates echo over millennia in our algorithms was very eerie,” he said.

Not ready for the clinic yet

Outside experts urged caution. Dr. Wilbur Lam of Emory University, who wasn’t involved in the study, called it “an extremely compelling study” with robust associations, but said its “true clinical utility... will need to be demonstrated prospectively,” and flagged open questions about how well it performs across different facial features, skin tones, and age groups.

Miroslaw Bober of the University of Surrey, also not involved in the study, said the findings shows “convincing evidence” of a statistical link but cautioned that “predicting an outcome is not the same as explaining it.”

He noted the study never tested whether the AI model picks up anything a doctor’s own assessment wouldn’t, since doctors’ general health evaluations weren’t measured for comparison. “This is a promising proof of concept, but it is not ready for clinical use,” Bober said.