Ending daylight saving time may prevent as many as 300,000 strokes annually

Daylight Saving Time is linked to a rise in heart attacks and strokes

Losing an hour of sleep with seasonal time changes is not good for our health and it’s linked to risks for the first couple days of Daylight Saving Time, including a short-term rise in heart attacks and strokes. Scientists theorize these elevated risks are linked to the disruption to the body’s circadian rhythm.

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.

The side effects of falling back and springing forward

Daylight saving time can interfere with a person’s sleep schedule, but it also has been linked to increased rates of depression, heart attack, stroke, cancer, and car accidents. UT Southwestern’s Dr. Joseph Takahashi explains why the time change is bad for your brain and health.

Daylight saving time, explained

Daylight saving time is supposed to help—but does it? Dive into the history, science, and consequences of this biannual aspect of American life (unless you're from Arizona or Hawaii).

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

Why people hated permanent daylight saving time in 1974

Messing with the amount of daylight each day has consequences, as America found out in 1974 when it first passed all-year daylight saving time. See why it was revoked less than a year later.

Circadian rhythm disruption can influence various mental health disorders

This 2020 research overview surveys the relationship between disrupted circadian clocks and disorders including schizophrenia, anxiety, and bipolar disorder. It incorporates findings and therapeutic approaches drawing from human night shift studies and jet lag studies alongside animal research.

There is a template for how to live a better, healthier day, and it includes a digital sunset

Science suggests that early-morning exercise, later-morning peak work or social time, consistent exercise, and a "digital sunset"—starting to turn down the lights in the evening and avoid screens—are important for circadian health.

Lack of sunlight during Arctic winters can fuel a winter slump and a circadian disconnect

Sunlight typically tells our brain to stop producing melatonin, a hormone that makes us sleepy, but in dark Arctic winters humans must adapt to life without much sunlight. Scientists in this video provide tips that include trying to increase the amount of light around you, even if it’s just table lamps.

Social jetlag—differing weekend and weekday schedules—is physiologically similar to jet lag

Recovering from schedules that drastically differ between weekends and weekdays, something that was first described in academic work in 2006, is a growing concern in public health as more research shows that consistent daily routines are important for human health.

Rising sea levels due to climate change may be slowing Earth's rotation

A 2024 PNAS study found that from 2000 to 2020, the length of a day increased at a rate of 1.33 milliseconds per century, an unprecedented amount in the 3.6 million years of day-length changes reconstructed from an analysis of benthic foraminifera fossils. Researchers suggest the slowing comes from changing ice sheets redistributing planetary mass.

World records are often broken later in the day—and scientists wonder if muscle clocks explain the difference

For reasons that are still not entirely clear, on average, people tend to lift more weight and achieve other exercise feats later in the day. Theories to explain this discrepancy include muscle clocks are at peak performance in the afternoon and that there's morning-to-afternoon variation in core body temperature, hormones, and neural activity.

Just a 10-minute mental health break can yield benefits

The US CDC offers recommendations for alleviating stress in daily life. Short 10-minute breaks can significantly improve mental health, especially when used for activities like deep breathing, dancing, or writing down things you are grateful for. Building meaningful relationships, termed "social connectedness," can also alleviate stress and promote resilience.

Dangers of a record-breaking, sleep-skipping stunt

In 1963, 17-year-old Randy Gardner decided to stay awake for as long as it took to break the current world record. He managed to stay awake for 11 days. In 2017, the then-71-year-old Gardner told NPR that his experience had come back to haunt him as insomnia. The challenge has since been removed from the Guinness Book of World Records due to its dangerous consequences.

For centuries, it was common to sleep in two shifts: a few hours at the beginning of the night, and a longer period beginning around midnight

Why time ticks faster on the moon, which may need its own time zone

Because Earth exerts a stronger gravitational pull than the moon, it lags behind between 56 and 59 microseconds each day, or about one second every 46.5 years. This impacts essential synchronous operations of future electronic equipment on the lunar surface, which could be alleviated by a standardized conversion system between Earth and moon time zones.

Continual sitting harms your health in a variety of ways

Prolonged inactivity, like sitting for long periods, slows metabolism, weakens muscles and bones, and impairs insulin function. When these negative changes persist over time, the cumulative result is an increased risk of cardiovascular disease, diabetes, and many cancers.

The Year 2038 problem is the next potential computer time rollover bug

Many older systems store time as a signed 32-bit integer counting seconds since Jan. 1, 1970. That counter maxes out on Jan. 19, 2038—overflowing into negative time and sending clocks back to 1901, potentially crashing any older software that depends on accurate dates.

Adults need two days of muscle strengthening activity weekly—yet most of us aren't doing that

That recommendation—muscle-strengthening activities on two or more days a week working all major muscle groups—is in addition to 150 minutes weekly of moderate-intensity physical activity. Those resistance and aerobic training numbers from the US government are echoed by other medical groups. But nearly 80% of adults aren't checking the box on those goals. This failure is linked to about $117B in annual health costs and some 10% of premature mortality.

An estimated 2 million brain cells die each minute a stroke goes untreated

Modern stroke treatment is a delicate balance between obtaining an accurate diagnosis and delivering treatment quickly. Each stroke has its own cause, and the appropriate treatment must be paired with the correct diagnosis to prevent further harm. Typical treatments pair emergency surgery to relieve the affected area and long-term regimens to avoid recurrence.

Noise from data centers may disrupt wildlife and local residents

Individuals living where local ordinances have allowed data centers to be built next to residential areas have reported that the constant humming and vibrations from cooling systems have prevented them from sleeping and exposed them to chronic noise, which the American Public Health Association says can lead to cardiovascular disease and increased stress.

Lightning may kill as many as 320 million trees each year

Ignoring the effects of tree loss resulting from lightning-induced wildfires, researchers at the Technical University of Munich developed a quantitative model to estimate the loss of these organisms due to cloud-to-ground strikes, based on global lightning data and forest structure. They expect the estimate to rise due to increased strikes resulting from climate change.

Extending the worldwide lifespan by one healthy year is worth $38T

This econometric study attempts to estimate the economic value of increasing the global healthy lifespan by one year—and to answer the question of whether it is better to extend lifespans or slow the rate of healthy aging.

The body's master clock has 20,000 neurons

The suprachiasmatic nucleus, the master clock in mammals, has 20,000 neurons that help maintain the light-dark cycle in the body. Among its jobs: It receives light input information from the retina and then signals peripheral body clocks to act on this information, driving everything from body temperature to hunger.

The hidden effects of March Madness

March Madness isn’t just a major sporting event—it’s also peak season for vasectomies. Urologists report a 50% increase during the tournament, as patients use recovery time as an excuse to watch nonstop basketball. Meanwhile, workplace distractions from bracket pools and game streaming are estimated to cost US businesses $17 billion.

Government shutdowns can cost the US economy billions

The Congressional Budget Office estimated that the 2018-19 shutdown reduced economic output by about $11B, including a permanent loss of roughly $3B

Some renewable energy sources may weaken the resiliency of electric grids by removing outage buffers provided by coal- and natural gas-fired plants, which provide the system with more time to find a new power source if a plant goes down.

11 people died from firework injuries in the US in 2024.

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

About 2,000 US babies are born annually without some portion of their limbs, potentially leading to a lifetime of pricey prosthetics.

Ebola infects and disables immune cells, triggering a cascade of events that leads to small blood clots throughout the body, weakening blood vessels and interrupting blood flow to key organs.

Indefinite cloning of some endangered species may not sustain their longevity because cloning success rates decrease as genetic mutations accumulate.

Stars appear to twinkle because turbulence in the motion of molecules in Earth's atmosphere causes light to bend and wiggle rapidly on its way to the surface—a phenomenon called scintillation.

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.

Explore chaos in this simulation of two double pendulums, where small differences in the release angles produce wildly different outcomes.

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

Up to a million Girl Scouts sell about 200 million cookie boxes every spring, generating $800 million, largely because refusing a child is frowned upon

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

Use this calculator to find the dollar value of your mental load, from meal planning to coordinating after-school care for your children.

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

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.

The US Constitution is widely regarded as the longest-standing written national constitution still in force—see how it has influenced rights worldwide.

Dozens of S&P 500 stocks, including Coca-Cola and Walmart—known as the dividend aristocrats—have increased dividends every year for 25 years

Mark Twain spent decades feuding with the US Postal Service, convinced its costs and regulations were bureaucratic overreach.

Apeirophobia is an overwhelming fear of living forever, perhaps stemming from the brain's inability to conceptualize an infinite life.

In 1945, Surrealist artist Salvador Dalí and legendary animator Walt Disney began collaborating on a short film that was not completed until 2003, years after both men had died.

Take a 3D tour of the Hajj, Islam's annual pilgrimage to Mecca, undertaken by more than 1.5 million Muslims each year.

70 years ago today, city officials in Santa Cruz, California, banned rock 'n' roll to protect its youth from corruption after witnessing a 'provocative' concert the night before.

NBA superstar Victor Wembanyama spent the 2025 summer training with monks in central China to enhance his body and mind.