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

Using fitness wearables to track muscle wasting in astronauts

All that exercising, and astronauts still are likely to lose a large amount of muscle mass while in microgravity. Astronauts can lose up to 20 percent of their muscle in as little as five days in space. Currently, tracking muscle loss means waiting until astronauts land to remeasure their muscle density post-trip. This article explains a NASA-backed fitness wearable that may be able to track muscle atrophy as it happens.

Healthy adults should perform 'progressive resistance training'

That's the recommendation in March 2026 from the American College of Sports Medicine. They reviewed existing studies on the topic and concluded that resistance training with progressively more weight and repetitions improves muscle strength, size, power, endurance, gait speed, balance, and more.

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.

Physiological muscle memory allows us to quickly regain lost musculature

The term "muscle memory" is most often associated with the neurological kind, which involves the development of strong and efficient neural pathways in the brain and spine. Physiological muscle memory also slows the loss of muscle mass, with both types affected by genetics and diet.

Women experience heightened bone loss after menopause

Both women and men begin to lose some bone density after age 35, on average, but for the first decade after menopause women lose bone more rapidly due to the significantly decreased levels of estrogen, putting women at heightened risk of osteoporosis and related bone fractures.

Cellular aging and deterioration leads to tissue (and overall) aging

Cells are the building blocks of life, forming tissues and organs that keep our bodies working. As we age, cellular changes have progressive consequences on both the structure and function of our organs. This article examines this complex relationship as it relates to the incremental changes associated with aging.

Muscles fatigue due to the loss of energy like ATP and glycogen

Adenosine triphosphate fuels muscle contraction, and with each contraction (like during exercise), the amount of ATP reduces. ATP helps potassium and sodium move across muscle membranes, generating ions and helping to contract the muscle.

How trauma gets ‘under the skin’

A study examining the muscle function of older adults who have at least one adverse childhood experience (ACE) suggests that trauma digs itself into muscle cells. Participants who reported childhood trauma were found to have lower maximum levels of cellular energy than people who reported fewer or no ACEs. Such compromised mitochondrial function "doesn't bode well," as it relates to a variety of health and age-related outcomes.

Yoga can be beneficial for aging practitioners

Studies suggest that yoga can help alleviate several diseases associated with aging by lowering blood pressure, reducing blood fat levels, and combating obesity. It has also been shown to increase telomerase activity, which helps slow cell aging.

External factors, not aging itself, lead to sleep loss in older adults

Though it is often believed that people need less sleep as they age, the recommended sleep guidelines for all adult age groups are almost identical. However, factors such as medication use, lack of physical activity, and loneliness can lead to sleep problems, and thereby lead older people to believe that they actually need less sleep than they do.

Estimates suggest inactivity contributes to 6% of deaths worldwide

The World Health Organization identifies physical inactivity as the fourth leading modifiable risk factor for global mortality, just behind hypertension, tobacco use, and high blood glucose. Latest estimates are that inactivity contributes to 6% of deaths and significantly increases the burden of chronic diseases like heart disease, diabetes, and cancer.

Collagen supplements have become a multibillion-dollar industry

Beginning in our 20s, the amount of this protein in our skin, muscles, and connective tissue declines. But independent, high-quality studies—like those that are double-blind—have not yet shown a significant association between their use and evidence of it improving skin elasticity, reducing wrinkles, or combating hair loss. Some collagen supplements do seem to help with joint pain and knee function, but NPR cautions that studies on that purpose are industry-funded.

The nutrients vegetarians and vegans need to keep in mind

Although most older Americans still enjoy their steaks and chicken, an estimated 2.5 million of those ages 55 and older have abandoned red meat and poultry in favor of a predominantly plant-based diet. Some people decide to go vegetarian or vegan...

The number and quality of sperm in men's semen is down, giving rise to various movements to avoid 'spermpocalypse'

A typical fertile, healthy young man produces over 100 million spermatozoa, or sperm cells, in his testicles every day. Scientists agree sperm figures are generally moving in the wrong direction, but also emphasize there's still a lot to learn about sperm.

People with schizophrenia typically die 9 years earlier than the general population

The syndrome, which affects roughly 1 in 233 adults, is often associated with other serious health issues, including cardiovascular, metabolic, and infectious diseases, which may contribute to early deaths. The side effects of long-term antipsychotic medications also may influence the mortality timing—weight gain, for example, is a common side effect of the drugs and can contribute to cardiovascular issues.

The human brain only uses 5% more energy during active tasks versus resting

Despite only being 2% of the weight of a human body, the average adult brain consumes 20% of its energy, with the majority of it spent on maintaining homeostasis—the stable equilibrium conditions of temperature, acidity, blood sugar, and other properties in the body. For infants, the consumption is closer to 50%.

The most common type of arthritis is osteoarthritis, or age-related cartilage loss

The most common form of arthritis is osteoarthritis. It's caused by cartilage loss within our joints as we age. This article is formatted specifically for patients. It provides easily digestible information on our most evidence-based understanding of osteoarthritis causes, symptoms, and treatments.

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

Alzheimer's can cause brain shrinkage of between 10% and 30%

While the exact cause of Alzheimer's is debated, the buildup of amyloid plaques and tau protein tangles is instantly recognizable in post-mortem examinations. The atrophy of brain cells caused by this molecular pileup leads to noticeable physical changes, including significant shrinkage in affected brain regions.

Americans are retiring later than they used to

A Gallup poll from 2022 found that the percentage of adults between the ages of 55 and 74 who are retired is declining.

Post-polio syndrome occurs decades after infection but isn't contagious

Affecting adults who contracted polio as children, this disorder can occur 15 to 40 years later, leading to slow, irreversible muscle weakening. Some research estimates that between 25% and 40% of polio survivors go on to develop this condition.

'Old people' smell is real—it's a chemical buildup when fatty acids on the skin oxidize

The chemical composition of body odor seems to change with age. Later in life, we harbor higher concentrations of a chemical compound called 2-nonenal that forms when omega-7 fatty acids on the skin oxidize, and the skin's natural antioxidant defenses weaken. Commonly called "nonenal", it's the smell widely associated with aging, and it's often described as a grassy or greasy odor.

Roughly 90% of generational wealth dries up by the third generation, epitomized by the phrase 'shirtsleeves to shirtsleeves in three generations'

Several factors can influence how wealth is passed down from generation to generation, but some of the main threats are mismanagement, estate taxes, and an expanding family tree.

About two-thirds of humans lose their ability to produce lactase after weaning

Lactase is an enzyme that digests lactose—a sugar in milk and dairy products. While genetics strongly determines lactase persistence, factors like famine, disease exposure, and gut bacteria also influence symptoms and evolution.

Explaining the rise in adult sports leagues

Community sports leagues shifted from publicly supported entities to privatized ones in the 1990s, as tech advances streamlined registration processes. Millennial interest drove significant growth in social sports leagues for adults, growing much faster than other kinds of sports. A few industry leaders have benefited from this shift.

Is metabolism related to weight loss?

Read this article to better understand metabolism and why doctors say it's only one piece in the puzzle to managing weight. Metabolism breaks down and converts what we consume into energy, which provides fuel for all of our body's functions—both...

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

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

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

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

About 12.5% of US adults experience a phobia in their lifetime, a diagnosis that hinges on the intense fear interfering with daily life and persisting for at least six months.

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.

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

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.

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

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.

Firework or sparkler burns, even if they cover a relatively small area of skin, can significantly affect our range of motion.

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.

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.

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

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.

In 1939, baseball star Lou Gehrig delivered his inspirational 'Luckiest Man' speech after retiring due to the health condition that now bears his name.

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.

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

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.

Volcanoes 'die' when their supply of magma runs out, if they are shifted away from their underlying magma reservoir, or if they get clogged by collapsing or their magma cooling back into rock.

Art theft is the third-largest source of criminal revenues worldwide, thanks in part to the subjective nature of valuing a work of art.

Gerrymandering works through two techniques: cracking opposing voters across districts to dilute their power, and packing them into a few to waste their votes in lopsided majorities.

The word 'jazz' evolved from 'jasm,' 19th-century American slang for 'energy'

For centuries, Niagara Falls has been a magnet for daredevils seeking to conquer one of nature's most powerful wonders, with its 200-foot drop and water rushing at 32 feet per second with 280 tons of force.