Most things you would get tested for at the doctor’s office are influenced by circadian rhythm

Studies suggest when you sleep is as important as how much you get

"Molecular clocks" made of timekeeping proteins and genes help regulate the body and its processes, meaning the disruption of one cog will impact another. Those who live in sync with their circadian rhythms report less fatigue, clearer thoughts, greater medication benefits, and better long-term health outcomes.

Studies suggest when you sleep is as important as how much you get, and syncing with your circadian rhythms may lead to less fatigue and improved long-term health outcomes

Temperature and certain medications can also affect your circadian rhythms

Although light and dark have the largest influence on circadian rhythms, temperature, stress, and certain medications are among the factors that also play a role. Persistent trouble sleeping or staying asleep may signal it’s time to see your doctor to get a better sleep-wake schedule.

There is a best way to wake up—but not a best time

Sleep and circadian rhythm researchers say that waking up at a consistent time each day—even on weekends—and viewing morning sunlight are the best ways to keep body functions running at their peak. (Some users may encounter a paywall.)

Circadian rhythms shift as we age—making older adults want to go to bed earlier

Throughout our lives our internal biological clocks shift. Early-to-rise toddlers become hard-to-wake teens and eventually early-to-sleep seniors. Circadian rhythm fluctuations throughout our life cycle explain some of these changes.

Parasites have circadian rhythms, too

Researchers are working to unravel how circadian rhythms of parasites and their hosts affect one another. They’re investigating how to potentially target and disrupt those clocks for disease treatments.

How meal timing factors into health outcomes

The world is trending toward weight gain, a development that comes with a corresponding rise in risk for health conditions, including diabetes and heart disease. This article explores how meal timing has become a factor in nutrition and weight maintenance.

Certain vaccinations may be more effective when given around the middle of the day

A 2023 analysis of the health records of more than 1.5 million people in Israel suggests that COVID-19 vaccines may be more effective when received around the middle of the day. Separate early research also suggests there may be similar trends for influenza vaccines.

Doctors are prescribing social activities—and seeing good results

Physicians, especially in the UK, are asking patients what they enjoy and then prescribing a consistent regimen of doing that type of activity to improve fitness and overall health, including community exercise classes, volunteering, and spending time in nature. This approach may provide better incentives to stick with an activity.

Heart attacks are less harmful at night

When heart attacks occur during the day they typically do more harm to the heart tissue than if they occur at night. A 2025 study suggests that daytime heart attacks have higher levels of immune cells called neutrophils to contend with and they appear to worsen the injury. Scientists confirmed this same pattern in experiments with mice. (Some readers may experience a paywall.)

Addressing lifestyle factors, which influence inflammation, can cure some chronic diseases

In this video, a physician claims that he reversed a patient's Type 2 diabetes in six weeks by addressing inflammation drivers such as diet. More broadly, he argues that society needs to better consider and address numerous disease factors that are modulated by inflammation, such as stress, sleep, diet, and movement.

Staying on standard time permanently would slightly reduce obesity and stroke risk

A 2025 study that examined time changes found that permanently changing to standard time would slightly reduce obesity and stroke risk more than switching to permanent daylight saving time.

Blood pressure readings correspond to the peaks and valleys of heart beats

Pushing 2,000 gallons of blood through the body every day exerts a force known as blood pressure. Blood pressure is highest during the heart's contractile phase, known as systole, which forces blood through the circulatory system, and lowest during the heart's resting phase between beats, known as diastole.

SAD uniquely affects people with attention-deficit hyperactivity disorder

Those with ADHD—chronic issues with attention and executive function—are primed for SAD. Many are disproportionately evening chronotypes (more awake in the evening), have a delayed sleep phase, and have low sensitivity to light in the morning. This podcast explores the overlap between these two groups.

Small ways to improve your health today: an animated guide

What are some ways that you could start making a positive impact on your health today? This animated gallery overviews several health topics, including sleep and hydration, and offers ways to improve that aspect of your life. Clicking on the...

Stress can be contagious—and scientists want to learn more about it

Researchers have shown that being around someone who is stressed can trigger a stress response in your body, such as elevated cortisol levels and elevated heart rate. One way this was recently studied was by having people watch stressful activities, like a recorded job interview or solving challenging math problems, and then sampling hormones in observers' spit.

Why Friday surgeries are (likely) riskier

Scheduling surgery on a Friday may lead to more complications—up to 5% more often—compared to surgeries performed after the weekend. The research was conducted by a team from the United States and Canada and analyzed data from over 450,000 patients who underwent common surgeries in Ontario between 2007 and 2019. Check out their findings here.

Doctors use three key physical markers to determine biological aging

The length of the ends of chromosomes (known as "telomeres"), the gradual change in collections of DNA molecules called "methyl groups", and the secretion of inflammatory proteins are all used as indicators of biological age.

An engineer tracked his moods for decades and helped researchers identify SAD

Civil engineer Herb Kern had bipolar and would record his moods dating back to 1967. He noticed the seasons were a major factor in the increase and severity of his episodes. By reaching out to researchers at the National Institute of Mental Health, Kern became the first human to confirm increased melatonin levels during winter and to receive bright light therapy.

Read the Surgeon General's 2023 loneliness report claiming loneliness is an epidemic

This report details the specific health threats linked with loneliness, including that loneliness and social isolation can increase the risk of premature death by nearly 30%. Loneliness lowers our capability to mount an effective immune response to viruses and respiratory illness, can cause chronic inflammation on par with physical inactivity, and increases the risks for anxiety, depression, dementia, heart disease and stroke.

Stroke risk doubles each decade after age 55

While age is the greatest risk factor, genetics, diet, and overall health play a prominent role in determining individual stroke risk. Prevention focuses heavily on modifiable risk factors. High blood pressure is the single most important controllable risk factor, contributing to both types of stroke.

Home allergy tests don’t work well and experts urge caution

Doctors do not recommend at-home allergy test kits because their results may be inaccurate and confusing, and lead people to make lifestyle changes that are not warranted. Tests that require sending in a hair sample, for example, will not be helpful because hair does not have the relevant antibodies that blood testing would detect.

Exercise helps make your arteries more elastic

Regular aerobic exercise releases nitric oxide, a key molecule that relaxes blood vessel walls and improves vascular function. These exercise-induced adaptations make the heart work more efficiently and blood vessels become more elastic, leading to improved circulation and lowered cardiovascular risk.

It's never too late to start hormone replacement therapy for menopause symptoms

This board-certified gynecologist discusses how it's ideal to start estradiol as soon as possible after menopause to maximize its benefits, but that if older women have healthy hearts they can still start these medications later, in consultation with their doctors, and the products could be useful if women are continuing to suffer from symptoms of menopause or want to fight bone loss.

Visualizing how American men and women spend every hour of the day, by decade of life

Drawing on three years of Census time-use data, the tool tracks 12 activities—sleep, work, housework, caregiving, TV, and more—across age groups from the 20s through 70s. One persistent gap: women spend 45 more minutes per day on housework than men on average.

A doctor answers the internet's burning questions about the gut

Gastroenterologist Dr. Ugo Iroku answers the internet’s burning questions about digestion and bowel movements. Get the lowdown on what it means when your stuff is super dark, the impact of coffee on evacuating bowels, and much more.

Telehealth demand for GLP-1s for weight loss is booming as consumers seek easier access.

The hormonal disorder PCOS was renamed PMOS in 2026, a move designed to improve care and research by shifting the focus to the hormonal causes of this condition that affects 1 in 8 women.

Learn how your body is, scientifically, like a firework with its own slow, controlled burn.

Alzheimer's can lead to brain shrinkage, with an average of around 2% of volume reduction per year

Listen to an in-depth conversation on the links between Parkinson's disease and herbicide exposure and the challenging pace of scientific investigation.

Doctors differentiate between a phobia and fear by asking patients whether their fear interferes with their day-to-day activities.

Hookworm infection, though risky, may help fight certain autoimmune conditions by tamping down the immune system's inflammatory response.

44% of Americans say they pray at least once a day—discover how your state's religiosity stacks up against the rest of the country.

At the beginning of the 20th century, a group of young men ate standard American food—replete with food additives like borax and formaldehyde—as part of government research to better understand food safety.

Astronauts have repaired genetic damage in space using CRISPR—a molecular tool that can make precise changes to DNA and is used in single-celled organisms to attack invasive viruses.

Cultural norms about how to handle the bodies of loved ones in communities in West Africa have hampered Ebola responses.

Bone marrow (soft tissue found inside certain bones) generates roughly 500 billion new blood cells each day

As of 2025, the most cited papers in science include a review of graphene, methods to improve image recognition, streamlining electron density calculations, and optimizing protein studies.

Poison ivy can cause rashes year-round since all parts of the plant contain urushiol, the oil that triggers our allergic response.

While the sun's gravity keeps the planets in orbit, their gravity also pulls on the sun, causing it and everything else in the solar system to orbit around a mutual balance point called the barycenter—the true center of the solar system.

While El Niño moves warm Pacific Ocean waters east along the equator, La Niña moves them west, shifting where rainfall will become more common for months.

Children are now three times more likely to say they want to be a YouTuber when they grow up than an astronaut, with some even attending 'YouTube camps' that teach kids how to create content for the platform.

Play the role of a student in a game where you try to navigate college and remain debt-free, selecting different income levels, high school experience, race, ethnicity, and more.

When you complete a CAPTCHA on a website to prove you are human, you may be unknowingly training algorithms for self-driving cars, whose systems require training data to help identify crosswalks, bicycles, and other outdoor objects.

Learn how to read a prospectus, the juicy document that any company must file with the SEC before going public.

The US dollar is the most widely circulated currency in the world, and is involved in nearly 90% of global transactions

Coral polyps reproduce via broadcast spawning, where entire reefs simultaneously release reproductive cells for about one hour, once a year.

After the Boston Tea Party, colonists switched to coffee, which became the main morning drink for revolutionaries.

Visualize the path of every solar eclipse from 1900 to 2099 and see what each looks like when observed from different locations on Earth.