Using fitness wearables to track muscle wasting in astronauts

Microgravity environments reduce muscle mass and bone density

Muscles that assist with balance and resistance to gravity are not subjected to their usual workload on the International Space Station. See the type of exercises that astronauts must complete for roughly two hours daily and learn why these movements are necessary to preserve astronauts' muscles, bones, and cardiovascular health.

Astronauts exercise on the International Space Station

Astronauts maintain bone, muscle, and cardiovascular health with physical activity. It's crucial astronauts make time to exercise for approximately two hours per day. This resource offers a behind-the-scenes look at how high-intensity workouts help prevent muscle atrophy, bone density loss, and aerobic decline during months-long space missions.

Prolonged space travel significantly impacts multiple human body systems

Astronauts can lose 20% of their muscle mass after two weeks and 10% of their bone mass after six months in space. Decreased sharpness of eyesight and changes in neural connectivity, brain structure and gut bacteria have also been observed.

There are no established minimum fitness standards for spaceflight

Microgravity is known to cause arterial hardening, bone weakening, and other health issues, but the novelty of space tourism and the minimal exposure time for suborbital trips have limited the number of research studies. Many companies have participants sign extensive waivers to bypass the requirement of specific medical standards.

Muted smell and taste in microgravity complicate meal enjoyment

Astronauts primarily consume freeze-dried meals, which are rehydrated with water recycled from urine and perspiration, directly from bags. Condiments and select cultural items from crew members can enhance the meal experience by boosting flavor. Many individuals report experiencing "food fatigue" due to a lack of fresh produce, limited menu variety, and lingering scents.

Adults may lose roughly 3% of their muscle mass each decade after 30

That muscle loss, formally referred to as sarcopenia [saar-ko-pee-nee-uh], averages 3% to 5%, depending on physical activity. These losses can progress with age, but resistance training helps combat some of this natural degradation.

Drugs in space: the pharmacy orbiting the Earth

Researchers are developing pharmaceutical solutions for astronauts, whose bodies may not respond the same way in space as they would on Earth. Similar to how microgravity causes changes to astronaut physiology, the environmental shift enables new...

How do astronauts battle loneliness and depression?

You’re stranded hundreds of miles away from your friends and family, constantly surrounded by coworkers who also are your roommates, and you’re only allowed the shortest of walks outside. There’s also no takeout, and gravity has essentially broken up with you. You might need a little help adjusting mentally. That’s where space psychologists and psychiatrists step in, according to this article.

Watch what it’s like to spend a day on the International Space Station

Microgravity makes personal care more complex on the International Space Station, where stray, floating materials must be captured to prevent them from entering vents and clogging filtration vents. No-rinse shampoo, water pouches, and other strategies help minimize obstructions.

Longer-duration space missions may amplify astronaut motion sickness

NASA is using the Kraken, a 50-foot-long, 100-ton US Navy research device, to simulate space motion sickness and vertigo and test possible recovery strategies, including testing out different, specific head movements. The Kraken, located at Wright-Patterson Air Force Base near Dayton, Ohio, can rotate participants at exposures of up to 3G.

NASA uses extreme Earth environments to prepare for space exploration

Analog missions in volcanic terrains and craters mimic Martian and lunar environments. Crew members operating in these missions, including at sites in Utah, Nevada, Arizona, and Hawai'i, test suits and specialized space instruments under simulated conditions.

Strength training appears to make for a healthier, youthful-looking brain

A study from 2025 links having higher amounts of muscle with a more youthful-looking brain age. Scientists analyzed data from more than 1,100 healthy adults around their mid-50s after they underwent full-body MRIs, comparing muscle, fat, and brain age appearances from the scans.Their findings link strength training and controlling visceral fat with improved brain health. The research didn't tease apart why this benefit occurs.

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.

Moving your body every day is key to longevity

In an era of biohacking, where millionaires subject themselves to draconian routines and tests to de-age themselves, one study suggests a super simple key predictor of mortality: more than any other trait, how much subjects moved determined how long they'd live. Movement mattered even more than age in predicting overall life longevity. Researchers suggest this means we should all simply get outside a bit more. Read more about the study here.

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.

A data visualization exploring six decades of spacewalks

Astronauts' initial small step for mankind may standout, but how many steps have we taken so far? Space and moonwalks further our understanding of spaceflight, celestial bodies, and space itself. Created to resemble a constellation map, this chart...

Do sleep-tracking apps work?

Can technology help us sleep better? As wearables and apps promise to optimize our nights, this New York Times investigation reveals some troubling findings after columnist Brian Chen used a wearable for two weeks to track his sleep. He discovered that sleep trackers not only provide frequently questionable data but can also paradoxically worsen sleep problems by causing users to obsess over their metrics — a new condition researchers are calling ‘orthosomnia.’

How does muscle memory work?

Muscle memory is less about remembering how to ride a bike and more about what's happening in muscle cells. Increasing the cells' size, say by working out, leads to an increase in nuclei, which increases the production of mitochondria. When your fitness regimen falls to the wayside and you decide to re-enter the gym, these gains-based nuclei are already present to quicken muscle cells' adaptation to exercise.

How to safely start 'Strengthmaxxing' with body weight—not actual weights

Beginning with exercises like a pull-up, for example, a weight training beginner can start in a "dead hang" with arms straight while grasping the bar and with feet off the ground. Then, lift your eyes to bar height before dropping again without any bouncing. Exercisers should feel like they've reached "failure" before they're done—meaning they feel like they could only do a couple more of the exercise if it was a life-or-death situation. (Some users may encounter a paywall.)

Weight loss lessons from 'The Biggest Loser' contestants

This article dives into findings from studies conducted on contestants of "The Biggest Loser" that look at the correlation between weight loss, weight gain, metabolism, and physical activity. The studies support the theory of metabolic adaptation,...

In 2013, an astronaut's helmet began filling with water during a spacewalk

A leak in the cooling system of Luca Parmitano's spacesuit caused water to obscure his vision and silence his radio as the International Space Station entered Earth's shadow, forcing him to feel his way back to the airlock in darkness.

A 15th-century university student documented a surprisingly detailed fitness plan

Modern fitness stems from the revolution in the knowledge we have of the human body, its cardiovascular systems, how muscles work, and more. Nonetheless, people through the centuries have had fitness regimes—including one university student whose fitness plan was preserved in an obscure document found between a manuscript.

Apollo astronauts left items in the moon's 'toss zone,' including golf balls, family photos, and bags of human waste, to make room for lunar rocks.

Hacking the body for a future that didn't happen

Journalist Adi Robertson experimented with one of the most accessible biohacks: magnets. Having a tiny magnet in their right ring finger meant they could sense magnetic fields, attract small metal objects, and more. But magnets weaken over time, eroding this new sense. Such implants do more than offer a new way of interacting with the world, they also pose new complications, such as the inability to get an MRI.

NASA funded research into creating pizza with a 3D printer

The agency awarded a contract for the development of devices that can create edible structures from long-lasting dry powders when mixed with liquids or pastes. By delaying this integration until the time of consumption, food could last longer than the current six-month expiration of freeze-dried meals for Mars expeditions.

In 2023, there were nearly as many payloads in LOE as trackable pieces of debris

In 2021, the European Space Agency estimated that more than 130 million space debris objects larger than 1 millimeter were in low Earth orbit, though only about 22,000 were being tracked. As of late 2025, the tracked total exceeds 49,000.

Voyager science teams still collect valuable space data using four active tools

These instruments track magnetic fields, solar wind particles, radio emissions from the heliopause, and hydrogen levels in the outer heliosphere. Even though each Voyager sends data at just 160 bits per second, NASA receives 6–8 hours of tracking data daily.

After 25 people used virtual reality headsets to practice flying with virtual wings—flapping their arms—their visual cortex responded to the wings almost as if they were real arms, treating them as body parts.

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

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

SpaceX's S-1 or 'prospectus' revealed many previously unknown details about the company, including its unprofitability despite doing $18.7B in revenue in 2025, exactly how many voting shares Elon Musk will have in the company (roughly 85%), and more.

Track the location of the Voyager probes, currently between 13 and 15 billion miles away from Earth.

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

Explore the known asteroids, comets, and spacecraft involved in asteroid studies within our solar system with 'Eyes on Asteroids,' a 3D visualization from NASA.

Read a deep dive on the 'all-purpose healing' peptide BPC-157.

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

To reduce wrinkles in clothing, research recommends gentle wash cycles with more water and tumble drying with smaller loads and longer times.

Fish populations in the Great Barrier Reef have increased after installing waterproof speakers on the ocean floor that played recordings of sounds from healthy coral reefs.

Planarian flatworms are small, aquatic worms with exceptional regenerative capabilities. When cut, the worms can regenerate multiple bodies in a matter of weeks.

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.

Double world record holder Hunter Ewen helped conquer his fear of balloons, called globophobia, by training to win Guinness World Record titles for balloon inflation.

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.

Tattoos remain visible on your skin thanks to immune cells called macrophages

In 1984, Operation Smash Hit intentionally crashed a 239-ton train into a nuclear waste canister at 100 miles per hour to prove the canister's safety, which remained completely intact and lost just 0.29 of its 100 pounds of pressure.

Most of the observable universe's volume consists of voids and supervoids—enormous regions of space with little to no galaxies, stars, or light.

Watch how algorithms can be designed to train themselves and self-improve without human input, to the point where the optimized code is too complex for programmers to understand.

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

Human-to-human transmission of hantavirus remains extremely rare, so the 2026 hantavirus cruise ship outbreak doesn't mean we're facing a COVID-style pandemic risk.

Use this tool to calculate the dollar value of your parental mental load, from meal planning to coordinating after-school care, then see resources that help generate solutions.

Some researchers have labeled nomophobia, the fear of being without your phone, as 'the phobia of the 21st century.'