Aging is a complex biological process affecting our cells, tissues, and organs.

Biological aging tests assess the breakdown of physiological systems

Known as aging clocks, these tests compare various metrics, like DNA methylation patterns and protein profiles, to healthy baselines. However, the non-uniformity of these baselines across individuals limits testing accuracy and prevents their clinical use.

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.

Each part of the human body experiences aging differently

With global average life expectancy cresting at 73 years, understanding how the body ages is imperative to effective medical treatment and maintaining a desired quality of life. This 13-minute video dives into how the body and its organs age "from head to toe."

Can humans delay or reverse old age?

We're not sure yet. Researchers at the University of California San Francisco are studying why some conditions and behaviors, such as low-oxygen environments and exercise, benefit the aging process, hoping to reveal potential health applications. Some of this research focuses on klotho, a naturally occurring age-regulating hormone named after the Greek Fate Clotho. Animal studies on klotho brain injections found subjects had improved memory recall and age-related degeneration resistance.

DNA damage and chemical stress causes cellular aging

While outward signs of aging, like gray hair and wrinkles, are easy to spot, aging changes at the cellular level are less obvious. The decline within cells stems from numerous sources, including DNA damage, oxidative stress, and accumulated waste.

Do people really look younger than they used to?

Why do people today look younger than they used to? From style to science, there are 3 surprising reasons we age differently now.

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.

Multiple new research paths may lead to slowing (or even reversing) aging

Aging has always been inevitable, but fasting, epigenetic reprogramming, and parabiosis seem to help people stay young. By studying centenarians, memory, and even the humble roundworm, scientists are looking for the genetic basis to live not just a long life, but a healthy one.

Aging explained with Dr. Nick Golinvaux

Aging is more than wrinkles and gray hair—it’s a gradual decline in cellular function. Over time, DNA damage, telomere shortening, and mitochondrial inefficiency contribute to weaker bones, slower memory, and reduced vitality. While aging is inevitable, regular exercise, quality sleep, and stress management maintain health and extend one’s years.

Aging results from the cumulative breakdown of cellular and tissue processes

A cumulative breakdown of cellular and tissue processes combines to result in decreased organ function, disrupting the systems driving normal human physiology. This five-minute video provides a primer on the subject, complete with a discussion of risk factors, cellular changes, and potential future treatments in the fight against aging.

The formula behind super agers—those possessing health and cognitive skills of people decades younger

A study of about 1,400 super agers did not identify any underlying genetic mechanism for longevity. While researchers instead emphasized that sustainable habits involving positive social connections, sleep, mood, diet, exercise, and personal fulfillment help reduce long-term risks, there is no one-size-fits-all formula for everyone.

Your brain appears to age in five distinct stages, with the pattern of connections inside your brain shifting, on average, around ages 9, 32, 66, and 83.

How aging degrades neural functioning in the brain over time

Aging affects the brain perhaps more than any other organ in the body. Throughout life, the brain experiences radical shifts in the number of neurons, synaptic connections between neurons, and hormone levels that regulate our mood and processing.

Perceived isolation ages you

Mounting evidence suggests that socialization is a vital component of maintaining good health. Research published in 2024 from Mayo Clinic researchers analyzed the social lives of more than 280,000 adults and concluded that individuals that weren't likely to participate in extracurricular social activities and get-togethers were more likely to have a biological age older than their actual age—meaning that you may be 60 but health indicators would suggest you're older.

Super-agers: seniors 80 and above with the memory ability of people in their 50s

Studies show the number one indicator of whether someone is a "super-ager" is not diet or genetics, but the extent of their social relationships. Moreover, scans reveal noticeable physical differences in certain parts of the brain in patients with extensive social networks.

Inflammaging is chronic low-level inflammation as we age, and it may be a key disease driver

The term refers to the idea that largely invisible but consistent low-level inflammation as humans age fuels chronic diseases and cellular aging. Inflammaging, this article says, is due to lifestyle factors like poor sleep, low levels of activity, and poor diet, acting in concert to cause cellular damage and trigger inflammation.

Environment and genetics explain why animals have widely different lifespans

Both environmental conditions and genetic factors shape how long various animals live. For some creatures, colder conditions allow for less energy use and slower aging. Larger animals have fewer predators. While humans don't live the longest, we are a rare species that successfully lengthened its average lifespan over time.

Health span: The number of years one is active and disease-free

As scientific advances continue to extend the average human lifespan, many are now turning their attention toward extending "health span." The ultimate goal would be to extend one's health span to match one's lifespan, which would necessitate a shift in focus toward the pursuit of healthy aging. (Some users may experience a paywall.)

Doctors shift focus from extending lifespan to lengthening health span

As scientific advances extend the average human lifespan, many are turning their attention toward extending "health span." Health span refers to the number of years one is active and disease-free. The ultimate goal is to extend one’s health span to match one’s lifespan.

According to the special theory of relativity, the faster objects move through space, the less they move through time, and therefore age more slowly.

Why do humans have such long childhoods?

Humans have over twice as long childhoods than other animals with similar lifespans like whales and elephants. A human child can grow for nearly 20 years before they become a reproducing adult. Researchers believe there's a connection between long childhoods and human's unusually large brain size, though the science is not totally clear. Dive into what scientists know here.

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.

Chronobiologists study the effect of time on biological cycles

Circadian rhythms were first observed in the 1700s, when French astronomer Jean-Jacques D'Ortous de Mairan put a plant in a dark room and watched it still respond to day and night cycles, setting off further studies about specific light-dark biological cycles, an area of inquiry that continues today with the human "clock proteins" at the molecular level.

Most self-reported claims of exceptional longevity are exaggerated, but read how demographers verify age claims and why some of the original blue zone demographers say blue zone regions are real and worth studying.

Where you are located in a gravitational field affects how quickly you age

The closer something is to the center of a massive object, the greater the strength of the massive object's gravitational field as a result of space-time being depressed more severely. Time passes more slowly the deeper an object is in this gravitational depression, meaning objects in the universe naturally seek to age more slowly.

Inflammaging appears to differ across global populations

Chronic, low-grade inflammation linked to aging is a byproduct of our industrialized lifestyles, according to recent research. The work compared two industrialized populations with two Indigenous, non-industrialized populations in Bolivia and Malaysia, and found that inflammation levels in the Indigenous groups—unlike the industrialized ones—did not seem to differ by age.

Less than 1% of aging studies consider menopause and its effects

Nearly all studies researching the biology of aging don't consider menopause in their setup. In part, that's because menopause is difficult to emulate in animal models. Menopause is uncommon in the animal world beyond humans and whales. This presents a problem for medicine and science because about 75% of aging-related diseases are likely influenced by menopause.

Paleontologists apply rules about rock layering, fossilization, and radioactivity to date geological samples

Concepts such as the understanding that older rock layers will form beneath newer ones allow scientists to compare the ages of samples from various layers. Although no geological site preserves evidence across all time, samples can be combined with fossils of known age, such as those dated by analyzing the decay of their radioactive isotopes, to reconstruct Earth's timeline.

The quest to find natural ways to extend lifespan

Tales of searching for the Fountain of Youth persist. Our modern-day version is marked by promises of pharmaceutical miracles and a proliferation of viral "biohacking" routines. One doctor’s quest to unlock the keys to longevity stimulated much of this renewed fervor, though his ideas are often taken out of context.

Cells can last in the human body from days to a person's entire life

Despite claims that a person's body replaces itself every seven to 10 years, the rate at which cells die and are replaced varies by cell type. Gastrointestinal cells that line the digestive tract and stomach last only a few days, while some heart muscle cells and most neurons are around from birth until death.

Blue zones are regions with unusually high numbers of centenarians

Factors thought to contribute to longevity in these regions include diet and social connections, but their legitimacy is often questioned due to a lack of rigorous scientific methodology and potential record inaccuracies.

One biologist is leading the blue zone criticisms—both questioning the original recordkeeping for these purported longevity-prone locations and pointing to recent research showing declining numbers of healthy seniors in several official blue zone regions.

The Dog Aging Project uses information from over 50,000 dogs to explore longevity

The study gathers health, lifestyle, and genetic data to understand what helps dogs live longer, healthier lives. Findings could also provide human health insights due to our shared surroundings and biology.

Roughly 10% of the world's population is older than 65 (2023 data)

With recent advances in medicine, sanitation, and nutrition, expected lifespans have rapidly risen around the globe—resulting in a rapidly aging global population. The worldwide distribution has seen a nearly 600% jump in the population of people aged 65 and older.