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Scientists at Howard University and the Chinese Academy of Sciences compared the genomes of 37 mammals to ask whether small long-lived species, such as bats and mole-rats, and large long-lived species, such as whales and elephants, reached long lifespans the same way. Using selection-intensity and evolutionary-rate methods on about 15,000 protein-coding genes, plus a published multi-species RNA-seq dataset, they report that the two groups share the phenotype but not the mechanism. Large long-lived mammals showed widespread relaxed selection but tight constraint on cell cycle and DNA repair genes, consistent with cancer suppression in large bodies. Small long-lived mammals showed constraint on autophagy, stress response, and mTOR pathway genes and stronger transcriptional signatures of DNA double-strand break repair. Selection intensity tracked maximum lifespan but not body mass.

Bigger mammals usually live longer. A mouse lasts a few years; an elephant lasts many decades. But some species break the rule. A Brandt’s bat weighing about as much as a few paperclips has been recorded living more than 40 years. A naked mole-rat can live past 37. At the other end, bowhead whales may exceed two centuries.

That raises an obvious question. Do these lifespan champions share a common biological secret, or did each lineage find its own way?

Olatunde Omotoso and Lotanna Micah Nneji sorted mammals into two groups. “Extremely long-lived small mammals” weigh a kilogram or less and live at least 15 years; these are mostly bats and mole-rats. “Body-mass-associated long-lived mammals” weigh at least 100 kilograms and live 50 years or more; these are mostly whales, plus elephants and a rhinoceros. A third group of ordinary mammals, from mice to sheep, served as the yardstick.

The researchers then looked for signs of evolutionary pressure across roughly 15,000 genes. When a gene matters a lot, natural selection tends to protect it from change. When it matters less, mutations accumulate more freely.

The two groups looked quite different. In whales and elephants, many genes showed relaxed protection, which is expected in large animals with small populations, where selection works less efficiently. But genes controlling cell division and DNA repair stayed tightly protected. That fits a long-standing puzzle called Peto’s paradox: an animal with a thousand times more cells than a human should get far more cancer, yet whales and elephants do not. Rigid control over cell division is one plausible answer, and it matches recent lab work showing bowhead whale cells repair broken DNA unusually well.

In the small long-lived species, the protected genes clustered elsewhere: autophagy, the cell’s system for recycling damaged parts; stress responses; and the mTOR nutrient-sensing pathway, the same pathway targeted by rapamycin. Gene activity data from liver and kidney told a similar story, with small long-lived species showing stronger activity in DNA double-strand break repair.

Very few individual genes were shared between the two groups. A handful were, including IGF1R, a growth-signaling receptor long linked to lifespan in lab animals, and LAMP2, a gene essential for one form of autophagy.

The authors also report that the overall intensity of selection across a species’ genome rose with its maximum lifespan but showed no link to body size.

The central idea is worth taking seriously. If the story holds up, the cancer-fighting tricks of giant animals may matter less for humans than the cellular maintenance strategies of small, long-lived ones.

Actionable Insights

How big are the lifespan gaps being explained? Using the study’s own body-size formula, the small long-lived species live on average 2.8 times longer than their size predicts, while the large long-lived species live only 1.3 times longer. Run a 70 kg human through the same formula and the expected lifespan is about 29 years; actual record human lifespan is 122 years, a ratio of about 4.2. On that measure, humans resemble bats far more than whales.

That suggests the “small mammal” maintenance strategy, autophagy, DNA repair, and stress resistance, may be the more relevant template for human aging. Behaviors and drugs that support autophagy or moderate mTOR activity, such as regular exercise, avoiding chronic overfeeding, and investigational agents like rapamycin, are consistent with this direction.

Context and Source

  • Open Access Paper: Convergent evolution of longevity reveals divergent genomic mechanisms in small and large mammals
  • Institutions: Howard University (Department of Biology); CAS Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Beijing; Aqualife and Environmental Stewardship Initiative, Lagos
  • Countries: United States, China, Nigeria
  • Journal: BMC Genomics, published online October 12, 2026
  • Impact evaluation: The impact score of this journal is 3.9, evaluated against a typical high-end range of 0-60+ for top general science, therefore this is a Low impact journal.

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Researchers at Victoria University in Melbourne tested beta-hydroxy-beta-methylbutyrate (HMB), a leucine metabolite sold widely as a muscle supplement, in the D2.mdx mouse, a severe model of Duchenne muscular dystrophy. Mice received HMB in drinking water at roughly 1 mg per gram of body weight daily for 8 weeks, starting at either 3 or 6 months of age. Treated dystrophic mice showed better whole-body grip strength, and their isolated fast-twitch extensor digitorum longus muscles produced more force, contained larger fibers, and had less inflammatory infiltrate. Mitochondria from fast-twitch fibers showed higher basal and maximal respiration, greater spare capacity, and more ATP production, without any increase in mitochondrial protein abundance. Phosphorylation of the mTORC1 targets p70S6K1 and 4EBP1 rose in fast-twitch muscle. Slow-twitch soleus muscle showed essentially no response. Benefits appeared at both disease stages tested. outside the dystrophy question: HMB increased muscle mass and fiber size in healthy 8-month-old mice but not in healthy 5-month-old mice.

Duchenne muscular dystrophy affects roughly one in 5,000 boys. The missing protein, dystrophin, normally anchors the muscle fiber membrane to its internal scaffolding. Without it, ordinary movement tears the membrane. The muscle degenerates, inflammation moves in, scar tissue replaces working fiber, and most patients lose the ability to walk in their early teens.

Gene therapies and exon-skipping drugs aim at the root cause. They are expensive, apply only to specific mutations, and have delivered modest clinical gains so far. That leaves room for cheap, safe interventions that address what goes wrong downstream.

HMB is one candidate. It is a breakdown product of the amino acid leucine, naturally present in the body, available as a supplement for decades, and with no documented toxicity even at high doses. Earlier work from this Melbourne group showed it helped young mdx mice, the standard but notably mild dystrophy model. The obvious objection was that mdx mice barely resemble human DMD, which raised the question of whether HMB would do anything in muscle that had already accumulated real damage.

This study used the D2.mdx mouse instead. Bred onto a different genetic background, it develops pronounced weakness and chronic inflammation by 3 months and substantial fibrosis and atrophy by 6 months. The team started HMB at both ages and ran it for 8 weeks.

Grip strength improved in both cohorts. Dissected fast-twitch muscle produced more force both in absolute terms and after correcting for size, meaning the tissue was not just bigger but better. Under the microscope, treated muscle showed larger average fiber size, less necrotic and inflammatory tissue, and higher succinate dehydrogenase staining, a marker of oxidative capacity.

The mitochondrial result is the most interesting part for anyone thinking about aging biology. Dystrophic mitochondria are known to run poorly: fragmented, calcium-overloaded, low on ATP. HMB raised basal respiration, maximal respiration, spare respiratory capacity, and ATP production in fast-twitch fibers from treated dystrophic mice. Yet western blots showed no change in the abundance of any of the five electron transport chain complexes. The machinery was not increased. It simply worked better. That points toward improved substrate flux, since HMB metabolism feeds acetyl-CoA into the TCA cycle, rather than mitochondrial biogenesis.

Two things did not happen. Slow-twitch soleus muscle showed no benefit on any measure: no force gain, no histology change, no signaling change. And the proportion of fibers with centrally located nuclei, a marker of repeated damage and regeneration cycles, was unchanged, suggesting HMB did not stop the underlying damage process.

Actionable Insights

For people interested in muscle aging: the dose matters. The mice got roughly 1,000 mg per kg of body weight per day. Converting by body surface area, the standard method, gives a human equivalent of about 81 mg/kg/day, or roughly 5.7 grams for a 70 kg adult. That is nearly double the 3 grams per day used in most human sarcopenia trials. The mouse result cannot be assumed to hold at typical supplement doses.

One detail outside the dystrophy question: HMB increased muscle mass and fiber size in healthy 8-month-old mice but not in healthy 5-month-old mice. If that pattern holds, HMB may matter more as muscle starts to decline than during the prime of life. Human sarcopenia meta-analyses point the same way, with modest gains in lean mass and grip strength in older adults.

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This review from the University of Wisconsin-Madison challenges the trend toward ever-higher protein intake. The authors bring together decades of animal research showing that dietary protein restriction improves metabolic health and extends lifespan in yeast, flies, and rodents, often without lowering total calories. They organize the evidence into six “hallmarks”: better metabolic health, altered nutrient sensing through GCN2 and mTORC1, less cellular senescence, improved mitochondrial function, epigenetic remodeling, and healthier aging with less frailty. The liver hormone FGF21 comes up again and again as a central mediator. The review argues that a few essential amino acids, mainly methionine, isoleucine, and valine, drive most of the benefit, while leucine probably does not. Short human trials show improved insulin sensitivity and lower body fat. The authors also stress that benefits are strongly sex-dependent and that older, frail, pregnant, or injured people may need more protein.

For years the nutrition message has pointed one way: eat more protein, especially as you get older. Grocery shelves now carry protein-fortified everything, and the share of Americans actively trying to eat more protein has climbed sharply since 2019. A new review from Dudley Lamming’s lab at the University of Wisconsin-Madison argues that, at least where long-term aging biology is concerned, the science points the other way.

The big idea is that protein is not just building material. It is also a signal. When animals eat less protein, their bodies read that scarcity and shift into a protective, maintenance-focused mode. Across flies, rats, and mice, low-protein diets have extended lifespan by roughly 10% to 50% in many studies, while improving blood sugar control, reducing body fat, and lowering frailty scores. Strikingly, this happens even though the animals often eat more food. They burn the extra energy off as heat.

The authors call the downstream effects the “hallmarks of protein restriction,” borrowing a framing popular in aging research. Low protein switches on a stress sensor called GCN2 and turns down mTORC1, the growth signal that the drug rapamycin also targets. Senescent “zombie” cells build up less in the liver, fat, and kidneys. Liver mitochondria produce fewer damaging free radicals. Chromatin marks shift.

A hormone made mainly by the liver, FGF21, sits at the center of the story. Protein restriction raises FGF21 in mice, rats, and humans. Mice engineered to overproduce FGF21 live about 30% to 40% longer. Mice lacking FGF21 get no lifespan benefit from a low-protein diet at all.

The review also asks which amino acids actually matter. The answer seems to be a few specific ones. Cutting isoleucine alone extended median lifespan by 33% in genetically diverse male mice. Cutting valine alone did the same for male mice by 23%. Restricting methionine has a long track record of extending rodent lifespan. Leucine, the amino acid most heavily marketed for muscle building, appears not to be a driver of the lifespan effect. The non-essential amino acids, long ignored because the body can make them, are messier: glycine supplementation modestly extended lifespan in a rigorous government-run mouse program, while extra arginine shortened fly lifespan.

There are important caveats, and the authors name several. Benefits are heavily skewed toward males. In one key study the same low-protein diet that extended male mouse lifespan by about 35% shortened female lifespan by 22%. Human evidence consists of trials lasting weeks, not years, measuring blood sugar and body fat rather than disease or death. Older adults are often already protein-deficient, and pushing them lower could accelerate muscle loss and frailty. Exercise appears to offset much of the muscle loss seen with lower-protein diets, which suggests a middle path.

The practical takeaway is not “cut protein.” It is that more is not automatically better, that protein quality and amino acid mix may matter as much as quantity, and that the right target likely depends on age, sex, activity level, and health status.

Actionable Insights

The evidence here is mostly from animals, so treat these as reasonable experiments rather than proven prescriptions.

First, question reflexive high-protein eating if you are under about 65, metabolically unhealthy, and not frail. Eating near the official RDA of 0.8 g per kg of body weight is not a deficiency. In mice, cutting dietary protein by about two-thirds extended male lifespan by roughly 10% to 35%, but human trials have only shown short-term gains in insulin sensitivity and fat loss, and the review does not report their magnitudes.

Second, shift protein sources toward plants. Plant proteins are naturally lower in methionine and the branched-chain amino acids, the components most tightly linked to the benefits in animals.

Third, skip standalone BCAA and leucine supplements. In one human trial, cutting BCAA intake by 75% for a week halved blood BCAA levels and improved insulin sensitivity.

Fourth, if you eat less protein, lift weights. Resistance training largely offset lean-mass loss on low-protein diets in a human trial.

Fifth, do not cut protein if you are older and frail, pregnant, injured, or eating very little (including people on appetite-suppressing drugs). For context, older adults eating 1.2 g/kg lost about 40% less muscle over 3 years than those eating 0.8 g/kg in an observational study.

Context and Source

  • Open Access Paper: The hallmarks of protein and amino acid restriction in aging and longevity
  • Authors: Bailey A. Knopf and Dudley W. Lamming
  • Institution: University of Wisconsin-Madison (Department of Medicine; Comprehensive Diabetes Center; Wisconsin Nathan Shock Center of Excellence in the Basic Biology of Aging) and William S. Middleton Memorial Veterans Hospital
  • Country: United States
  • Journal: Cell Press Blue, Volume 1, published August 17, 2026 (Review article)
  • Impact evaluation: Cell Press Blue does not yet have a Journal Impact Factor.

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In this mouse study from Guangdong Pharmaceutical University, researchers tested whether ergothioneine, a sulfur-containing amino acid concentrated in mushrooms, protects against overtraining. Young male C57BL/6J mice swam to exhaustion daily with tail weights for eight weeks while receiving ergothioneine (30 or 60 mg/kg/day), NMN (20 mg/kg/day) or saline. Overtraining cut swimming endurance by 58 percent, grip strength by 41 percent and rotarod time by 33 percent, and raised markers of inflammation and muscle damage. Both ergothioneine doses roughly doubled swim time relative to untreated overtrained mice, restored grip strength, lowered IL-6, creatine kinase and blood urea nitrogen, and raised muscle antioxidant enzyme activity. Treated mice had more Akkermansia in their gut, and muscle gene expression shifted in pathways linked to AMPK and PPAR signaling. With only five or six mice per group and no protein-level validation, the findings are preliminary.

Anyone who has trained too hard knows the feeling: heavy legs, weak grip, poor sleep and workouts that get worse rather than better. Researchers in China report that ergothioneine, a natural compound found in mushrooms, beans and oats, largely reversed these effects in overtrained mice.

The team at Guangdong Pharmaceutical University forced young male mice to swim to exhaustion every day for eight weeks, with a small weight equal to 8 percent of body weight attached to their tails. One group was left untrained as a comparison. The overtrained mice were given daily oral doses of ergothioneine at two levels, saline, or NMN, a popular longevity supplement that boosts the cellular energy molecule NAD+ and served as a positive control.

The overtraining took a heavy toll. Compared with untrained mice, overtrained animals could swim only about 42 percent as long, gripped about 41 percent more weakly and fell off a rotating rod sooner. Their blood showed higher levels of IL-6, an inflammatory signal, and of creatine kinase and urea nitrogen, markers of muscle breakdown. Their muscles held less glycogen, the stored sugar that fuels endurance, and their main antioxidant enzyme was less active. Under the microscope, muscle fibers looked loose and disorganized.

Ergothioneine changed the picture. Treated mice swam roughly twice as long as untreated overtrained mice, recovering about two-thirds to three-quarters of the lost endurance. Grip strength returned most of the way to normal. Inflammation and muscle damage markers fell, antioxidant enzyme activity rose and muscle fibers looked more orderly. The higher dose generally worked a little better. NMN produced similar benefits.

The gut also responded. Overtraining reduced Akkermansia, a bacterium associated with a healthy gut lining, and increased groups linked to inflammation. Ergothioneine reversed these shifts. In muscle, genes involved in fat metabolism, inflammation and the body clock moved back toward normal, with the strongest signals in the AMPK and PPAR pathways, which regulate how cells burn fuel.

The authors suggest ergothioneine works through its known antioxidant and anti-inflammatory actions, possibly helped by the gut. Recent work from Harvard has shown that ergothioneine builds up in muscle mitochondria during exercise and directly activates an enzyme called MPST, boosting mitochondrial respiration. This study did not test that mechanism.

The results should be read cautiously. Each group contained only five or six mice, all young males, and the gene and microbiome analyses used just three or four animals. Pathway findings were not confirmed at the protein level. Some blood measurements used unusual methods, including measuring cortisol in mice, which mainly make a different stress hormone. One corresponding author is affiliated with a private company that partly funded the study, although no competing interests were declared.

The doses are also high. Scaled to a person, they correspond to roughly 170 to 340 mg a day, far above the 5 to 30 mg used in human trials and approved for supplements in Europe. No human trial has yet tested ergothioneine for exercise recovery.

Actionable Insights

These are mouse results and remain unproven in people.

  1. Endurance recovery was large. Untreated overtrained mice swam about 12.6 minutes versus about 30 minutes for untrained mice. High-dose ergothioneine raised this to 26 minutes, recovering about 77 percent of lost endurance. Effect sizes appear enormous (d above 3), which in a five-mouse group mostly signals small, highly controlled samples rather than a reliable estimate of the real effect.
  2. Doses were high. Using standard body-surface scaling, 30 and 60 mg/kg in mice correspond to about 2.4 and 4.9 mg/kg in humans, or roughly 170 to 340 mg per day for a 70 kg adult. Human trials use 5 to 25 mg/day; Europe’s novel food approval covers supplements of up to 30 mg/day.
  3. Safety margin appears wide. The rat no-observed-adverse-effect level of 800 mg/kg/day translates to about 9 grams per day for a human.
  4. Food first. Mushrooms are the richest dietary source; cooking can lower content, and supplements in human trials have raised blood levels several-fold at 10 to 25 mg/day.
  5. Ergothioneine performed about as well as NMN here (71 percent endurance recovery with NMN versus 77 percent with high-dose ergothioneine), so stacking both is untested and may be redundant.

Context and Source

  • Open Access Paper: Ergothioneine alleviates exercise-induced fatigue associated with modulation of muscle transcriptome and gut microbiota
  • Institution: School of Pharmacy and School of Biosciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou; Key Laboratory of New Drug Discovery and Evaluation; and Xie Zhihui Biomedical Research Institute, Guangzhou Co., Ltd (a private company)
  • Country: China
  • Journal: Applied Biological Chemistry.
  • Impact Evaluation: Thee impact score of this journal is 4.2, evaluated against a typical high-end range of 0 to 60+ for top general science and medicine journals, therefore this is a Low impact journal.

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In a two-year randomized controlled trial at UT Southwestern and Texas Health Presbyterian in Dallas, 61 healthy but sedentary adults aged 45 to 64 were assigned either to a progressive endurance program with weekly high-intensity 4x4 intervals or to a yoga, balance and flexibility control. The 53 people who finished were studied with invasive right heart catheterization and 3D echocardiography while the researchers raised and lowered how much blood was filling the heart. That let them map how stiff each left ventricle was. Exercise raised maximal oxygen uptake by 18 percent and cut the left ventricular stiffness constant by about 29 percent. Controls lost a little fitness, and their stiffness did not change. The exercisers’ hearts also grew larger without any rise in filling pressure. The authors argue that middle age is a window when sedentary cardiac aging can still be reversed.

A healthy heart, like a well-worn leather glove, is supposed to stay supple. In people who spend decades sitting, it does not. The left ventricle is the chamber that fills with oxygenated blood and pumps it to the body. It gradually stiffens, so that each extra milliliter of filling takes more pressure. By their late sixties, sedentary people can have small, stiff ventricles that look a lot like those of patients with heart failure with preserved ejection fraction (HFpEF). HFpEF is a common, stubborn form of heart failure with few effective drugs.

Benjamin Levine’s group in Dallas had already found two relevant things. Older lifelong competitive athletes have ventricles as compliant as those of people decades younger. But when the same team put sedentary people over 65 through a year of training, their ventricles barely changed. That raised an obvious question: is there an earlier window when the damage can still be undone?

To find out, the team randomized 61 sedentary but otherwise healthy adults, average age 53, into two groups for two years. One group followed a periodized program modeled on how endurance athletes train. It built gradually to five or six hours a week by month six and included the Norwegian 4x4 interval session: four minutes near maximal heart rate, then three minutes easy, repeated four times. The program also included a long session, steady base-pace sessions and two strength workouts each week. After ten months, the load eased to a maintenance phase with one interval day per week. The comparison group did yoga, balance and flexibility work three times a week and had the same amount of contact with research staff.

What sets the study apart is how it measured the heart. Instead of relying on ultrasound proxies, the researchers placed a catheter in each participant’s heart and then changed how much blood was filling it. First they pooled blood in the legs using a lower body negative pressure chamber. Then they rapidly infused warm saline. Pairing the pressure readings with 3D echo volumes let them draw each person’s pressure-volume curve before and after the two years.

Adherence was high, at 88 percent of prescribed sessions. In the 28 exercisers who finished, VO2max rose from 29.0 to 34.4 mL/kg/min, about 18 percent, while it slipped slightly in the 25 controls. The ventricle’s stiffness constant fell by about 29 percent in the exercise group and did not move in controls. The exercisers’ hearts also enlarged, with end-diastolic volume up roughly 17 percent at ten months. Because filling pressure stayed flat, the heart moved more blood per beat at any given pressure. Over the same two years the controls gained weight and lost blood volume, a small real-time picture of what sedentary aging does.

The big idea is timing. Read alongside the earlier null result in people over 65, these data suggest late middle age may be the last comfortable window in which the heart muscle and the sac around it can still remodel. That argument is circumstantial, because the two age groups were studied in separate trials with different programs.

There are other caveats. The volunteers were lean, had normal blood pressure, were mostly white, and were motivated enough to commit two years to a demanding program. That is not the profile of the people most likely to develop HFpEF. The analysis included only completers. The main outcome is a physiological surrogate: no one has shown that this program prevents heart failure or extends life. Even so, as a precisely measured demonstration that a sedentary middle-aged heart can be retrained, it is one of the stronger human datasets available.

Actionable Insights

What the trial prescribed:

  • Exercise four to five days a week, building up gradually over months. Weekly volume peaked at 5 to 6 hours between months six and ten, then dropped to a maintenance level of about 150 to 180 minutes.
  • Do at least one high-intensity session a week, the 4x4: four minutes at about 95 percent of peak heart rate, then three minutes of active recovery at 60 to 75 percent, repeated four times. Follow it with an easy recovery day.
  • Each week, add one long session of 60 minutes or more, steady moderate sessions, and two whole-body strength sessions.
  • Start before 65 if you can. The same group’s earlier work found little change in heart stiffness when sedentary people started after 65.

How big the benefits were:

  • Fitness rose by about 5.6 mL/kg/min more than in controls, roughly 1.6 METs. That is a large effect (Cohen’s d about 1.1): the average exerciser ended up fitter than about 86 percent of comparable controls.
  • In large observational studies, each extra MET is associated with about 13 percent lower all-cause mortality. By that association, this gain corresponds to roughly 20 percent lower risk. This is an extrapolation, not a measured outcome.
  • Heart stiffness fell about 29 percent, against 2 percent in controls, a moderate effect (d about 0.6).
  • Resting heart rate fell by 5 beats per minute.
  • Lean mass still declined about 1 kg in both groups. If you want to keep muscle, plan on harder strength work than this protocol included.

Context and Source

  • Open Access Paper: Reversing the Cardiac Effects of Sedentary Aging in Middle Age-A Randomized Controlled Trial: Implications For Heart Failure Prevention
  • Institutions: Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, and University of Texas Southwestern Medical Center
  • Country: USA, Baker Heart and Diabetes Institute, Melbourne, Australia
  • Journal: Circulation (American Heart Association), January 8, 2018.
  • Impact evaluation: The impact score of this journal is 41.3 (2025 Journal Impact Factor, JCR 2026 release), evaluated against a typical high-end range of 0 to 45+ for top cardiovascular journals (European Heart Journal is about 45), therefore this is an Elite impact journal.

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A narrative review from the University of Palermo argues that people who reach 100, 105 and 110 years do not keep a youthful immune system. Their immunity is heavily remodeled: naive T cells almost disappear, B cells decline, and natural killer cells, effector-memory CD8 T cells and an unusual population of killer-like CD4 T cells expand. What seems to set the longest-lived apart is not an absence of inflammation but better control of it. Inflammatory scores rise with age yet stay closer to young-adult values in many semi-supercentenarians, and in a large Japanese cohort a composite inflammation score predicted death, disability and cognitive decline even beyond 100. The authors frame extreme survival as successful accommodation of immune aging, shaped by sex, genes, infections and environment. The evidence is mostly cross-sectional, small and blood-based, so causality remains unproven.

For decades, immunologists have described the aging immune system as a story of decline. The thymus shrinks, naive T cells disappear, memory cells pile up, and a smoldering background inflammation, nicknamed inflammaging, wears down tissues. If that were the whole story, the oldest humans should have the most broken immune systems of all. A new review from the University of Palermo suggests they do not, and that the reason is more interesting than simple preservation.

Calogero Caruso, Giuseppina Candore and colleagues pulled together flow cytometry, single-cell sequencing and long-term cohort data on centenarians (100 and older), semi-supercentenarians (105 and older) and supercentenarians (110 and older). Their verdict is that these immune systems look old. Thymic output is close to zero, true naive T cells are rare and B cells decline. In one Japanese study, B cells made up about 2 percent of blood immune cells in supercentenarians compared with 11 percent in younger controls.

The interesting part is what expands. Natural killer cells, effector-memory CD8 T cells and, most strikingly, CD4 T cells that behave like killer cells all increase. In supercentenarians these cytotoxic CD4 cells made up a median of 17.6 percent of CD4 T cells, against 4.0 percent in people aged 70 to 99. Many came from a few large clones, consistent with decades of response to persistent infections such as cytomegalovirus, yet they showed little sign of exhaustion. The authors read this as a standing surveillance force against infected and cancerous cells, which would fit the very low cancer rates reported after 100.

The second theme is inflammation. Most centenarians carry higher inflammatory markers than young adults. Yet in a Sicilian cohort, the semi- and supercentenarians had composite inflammation scores closer to those of younger age groups. In a Japanese study of 1,554 very old people, a combined inflammation score predicted death in centenarians and semi-supercentenarians, while telomere length did not. The children of centenarians already had lower inflammation than their peers. Healthy centenarians also appear to keep NLRP3 inflammasome expression at young-adult levels, and lymphocytes from a small group aged 105 to 107 handled an oxidative challenge more like young cells than old ones.

Sex runs through everything. Women make up about 83 percent of Italy’s 23,548 centenarians and 19 of its roughly 20 living supercentenarians. The review links part of this to immune genes on the X chromosome that escape silencing and to slower inflammatory aging in women, alongside behavioral and environmental differences.

The unifying idea is immunobiography: each person’s immune system is sculpted by a lifetime of infections, vaccines, diet, microbes and stress. There is no single centenarian immune profile, only different routes to a workable balance between memory, killing power and inflammatory restraint.

The caveats are substantial. Nearly all the data are cross-sectional snapshots of blood, many cohorts number in single digits, and features found in survivors are labeled adaptive without evidence that they caused survival. Even so, the message for everyone else fits the wider aging literature: keeping chronic inflammation under control, more than keeping individual immune cells young, may be what tracks with a long and healthy life.

Actionable Insights

These are associations, not tested treatments: reasonable bets, not proven fixes.

  1. Measure and manage chronic inflammation. In Japanese adults aged 85 to 99, each step up in a combined inflammation score (IL-6, TNF-alpha, CRP, CMV antibodies) came with an 89 percent higher risk of death; in centenarians, 36 percent higher. Inflammation explained only about 9 to 11 percent of differences in physical ability and thinking. A high-sensitivity CRP test plus a routine blood count gives a cheap baseline: neutrophils times monocytes divided by lymphocytes is the SIRI index the Sicilian group tracked.
  2. Stay active. A single bout of exercise lowered TNF in centenarians, though the size of the drop was not reported.
  3. Keep vaccinations current. Vaccine-induced T cell memory can persist for 70 years, and centenarians carried antibodies to the 1918 flu at about 50 times the level of 70-year-olds.
  4. Eat for your gut. A Mediterranean pattern and daily fermented dairy feature in the record-holder’s profile, but that is a single person.
  5. Don’t panic over expanded memory or CMV-driven T cells on an advanced immune panel; in the oldest people these coexist with survival.

The biggest number in the paper, life spent with disease falling from 17.9 to 5.2 percent, describes supercentenarians, not a benefit anyone can buy.

Context and Source

  • Open Access Paper: Why Some People Live Past 100: The Role of the Immune System in Centenarians, Semi-Supercentenarians and Supercentenarians
  • Institution: Laboratory of Immunopathology and Immunosenescence, Department of Biomedicine, Neuroscience and Advanced Diagnostics, University of Palermo
  • Country: Italy
  • Journal: International Journal of Molecular Sciences (MDPI), 2026
  • Impact evaluation: The impact score of this journal is 5.6 (2025 Journal Impact Factor, Clarivate JCR June 2026 release; CiteScore 10.0), evaluated against a typical high-end range of 0 to 60+ for top general science, therefore this is a Medium impact journal.

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A cross-sectional study from UT Southwestern Medical Center and the University of Texas at Dallas looked at whether cardiorespiratory fitness is linked to brain structure across the adult lifespan. Fitness was measured directly as peak oxygen uptake (VO2peak) on a treadmill. The researchers scanned 172 sedentary but healthy adults aged 22 to 81 with 3-Tesla MRI and tested fluid cognition in 147 of them. Age was strongly associated with thinner cortex and lower gray matter volume throughout the brain. Fitness showed no association with total gray matter or average cortical thickness. One region stood out. In the right superior parietal lobe, volume fell with age among the less fit participants but stayed flat among those above the median fitness of 25 mL/kg/min. Larger volume in this region was modestly associated with better fluid cognition. The findings hint that fitness benefits the brain in specific regions, but they cannot establish cause and effect.

Your brain shrinks as you age. That much is well established, and this study confirms it in detail. Across 172 healthy adults aged 22 to 81, each extra decade of age came with roughly 3 percent less total gray matter and a measurably thinner cortex. The open question is whether anything you control changes that trajectory, and aerobic fitness has long been a leading candidate.

The researchers tested this with unusually rigorous measurements. Instead of relying on questionnaires or step tests, they put every participant on a treadmill and measured peak oxygen uptake directly, collecting expired air until exhaustion. Each person also had a high-resolution brain scan and a cognitive battery covering reasoning, long-term memory, working memory, processing speed and executive function.

The main result is less tidy than most exercise headlines. Once age, sex, education and head size were accounted for, fitness did not predict total gray matter volume or average cortical thickness. A trend toward thicker cortex in fitter people narrowly missed statistical significance. Across most of the cortex, age dominated and fitness seemed not to matter.

One region broke the pattern. The right superior parietal lobe sits near the top and back of the head and supports spatial attention, reasoning and working memory. Here the link between age and volume depended on fitness. Among participants below the median VO2peak of 25 mL/kg/min, volume fell by about 39 cubic millimeters per year, roughly 12 percent between ages 30 and 70. Among those above the median there was no detectable decline. People with more volume in this region also scored somewhat better on fluid cognition, even after accounting for age and fitness.

It makes sense that fitness would matter here. The parietal cortex is among the regions that thin early in mild cognitive impairment and Alzheimer’s disease, and earlier studies have linked fitness to parietal structure and blood flow. The region also sits in a vascular border zone where blood flow drops with age, so better cardiovascular function could plausibly protect it.

This is a single snapshot in time, so it cannot show that fitness slows brain aging within any one person. Fitter older adults may differ from less fit peers in body weight, blood pressure and medication use, and none of these were adjusted for. The sample was mostly white, highly educated and deliberately sedentary, which limits both who the results apply to and the range of fitness studied. The effect appeared in only one region of the cortex, and only for volume, not thickness.

What the study adds is gold-standard fitness measurement applied across the whole adult lifespan rather than only in older adults, plus a specific anatomical target for future trials. The real test will be randomized studies that raise VO2peak and track the right superior parietal lobe over years. Until then, the result is a promising signal rather than proof.

Actionable Insights

  • The fitness line that mattered was a VO2peak of about 25 mL/kg/min, roughly 7 METs. Above it, right superior parietal volume showed no age-related decline. Below it, volume fell about 0.3 percent per year, around 12 percent from age 30 to 70. At age 70, the fitter group’s predicted volume was about 14 percent larger. [Confidence: Low to Medium]
  • At the whole-brain level, the fitness effect was small and statistically uncertain. Each extra 10 mL/kg/min of VO2peak corresponded to total gray matter about 2 years “younger”. The data are consistent with anything from 4 years older to 8 years younger. Average cortical thickness looked somewhat better, about 5 years “younger” per 10 mL/kg/min, but this narrowly missed significance. [Confidence: Low]
  • The link between parietal volume and cognition is modest. After adjustment, parietal volume explained roughly 4 percent of the person-to-person variation in fluid cognition. [Confidence: Medium]
  • The practical move is to know your VO2peak, either measured or estimated, and train to raise it. Structured aerobic programs in sedentary adults commonly raise VO2peak by 10 to 20 percent. In meta-analysis, each 1-MET gain in fitness is associated with about 13 percent lower all-cause mortality. Treat the brain-structure benefit as a plausible bonus on top of well-proven cardiometabolic benefits, not a proven effect in its own right. [Confidence: Medium]

Context and Source

  • Open Access Paper: Associations of cardiorespiratory fitness with cerebral cortical thickness and gray matter volume across the adult lifespan, 2025.
  • Institutions: University of Texas Southwestern Medical Center (Department of Neurology); Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas; Center for Vital Longevity, University of Texas at Dallas; National Institute of Advanced Industrial Science and Technology, Japan (co-affiliation)
  • Country: United States
  • Journal: Journal of Applied Physiology (American Physiological Society), 2025.
  • Impact evaluation: The impact score of this journal is approximately 3.0 (Clarivate JIF; Scopus CiteScore approximately 5.9), evaluated against a typical high-end range of 0 to 60+ for top general science, therefore this is a Medium impact journal.

RapAdmin

Brown fat burns calories to generate heat, but this ability fades as we get older. This study maps out exactly why this happens: as fat ages, local immune cells begin releasing an inflammatory molecule (IL-1β) that essentially short-circuits the neighboring fat cells. This inflammation causes the fat cells to produce their own local stress hormones, which hit an internal “off switch” (the glucocorticoid receptor) and lock the brown fat in a dormant, low-energy state. In young, healthy bodies, cold exposure triggers nerve signals that clear out this inflammation, allowing the fat to turn back on and generate heat. However, chronic inflammation in aged fat blocks this natural response, leading to cold intolerance and a sluggish metabolism. Most importantly, researchers found that giving aged subjects a drug (RU 486) to block these local stress receptors successfully reactivated their brown fat, boosted their overall calorie burn, and restored their ability to adapt to the cold.

Brown fat acts as a metabolic engine, utilizing blood sugar and lipids to generate heat rather than storing them. The gradual loss of this calorie-burning capacity during aging strongly correlates with metabolic decline and frailty. Recent analyses reveal that brown fat cells are not identical. They exist in two distinct states: a highly active, heat-producing state driven by the uncoupling protein UCP1, and a dormant, low-energy state. The transition between these states is tightly controlled by a localized interaction between the nervous system and the immune system.

The core regulatory mechanism identified in this research revolves around tissue-level inflammation. Immune cells residing within the fat tissue secrete an inflammatory molecule called IL-1β. This molecule acts on nearby brown fat cells to stabilize a specific enzyme known as H6PD, preventing its normal cellular disposal. H6PD acts as a catalyst for the local production of active stress hormones, or glucocorticoids, directly inside the fat tissue. These localized stress hormones activate the cell’s glucocorticoid receptor. This receptor activation subsequently shuts down UCP1 production, turning off the metabolic machinery required to burn calories and locking the cell in the dormant state.

When a young organism is exposed to cold temperatures, sympathetic nerves release neurotransmitters that directly instruct the immune cells to stop secreting IL-1β. Without this inflammatory signal, H6PD degrades, local stress hormone production plummets, and the fat cells transition into the highly active state to generate heat.

Aging severely disrupts this biological system. Older subjects exhibit a massive accumulation of IL-1β-secreting immune cells within their brown fat. This chronic, localized inflammation creates a continuous production of active stress hormones, even during severe cold exposure. Consequently, aged brown fat remains trapped in the dormant state, rendering the organism cold-intolerant and metabolically suppressed.

The defining breakthrough of this study is the pharmacological reversal of this age-related metabolic decline. By administering mifepristone (RU-486), a drug that blocks the glucocorticoid receptor, researchers successfully bypassed the immune-driven blockade. Antagonizing these stress receptors in aged subjects permitted the dormant fat cells to transition back to the highly active state. This intervention significantly raised whole-body energy expenditure and restored cold survival rates to near-youthful levels. This research isolates a precise pathway where localized inflammation drives metabolic aging, offering a targetable mechanism to restore calorie-burning capacity and systemic energy expenditure.

Actionable Insights

Systemic or tissue-specific interventions targeting glucocorticoid signaling present immediate translational potential for longevity and metabolic health. The data indicate that chronic localized inflammation (specifically IL-1β) directly suppresses metabolic rate by mimicking local stress signaling in fat tissue. Limiting systemic inflammation may preserve thermogenic capacity by maintaining the sensitivity of brown fat to noradrenaline.

The pharmacological blockade of the glucocorticoid receptor using RU-486 yielded substantial, quantifiable benefits in older subjects. In aged models exposed to cold for one day, RU-486 increased the population of high-thermogenic BA-H cells from a median of 10.6% to 32.8%. This represents an absolute increase of 22.2% and a relative increase of 3.09-fold (estimated Cohen’s d > 1.5, indicating a massive effect size). Functionally, this cellular shift rescued survival. Aged control subjects faced a 25% absolute risk of mortality within two days of severe cold exposure, whereas RU-486 stabilized body temperatures and mitigated weight loss, restoring functional thermogenesis. While chronic systemic RU-486 administration carries clinical side effects, this study was only 7 days long and demonstrated significant modifications and functional improvements. These findings suggest that a pulsed dosing strategy may provide signficant benefit, and also strongly supports the development of tissue-targeted glucocorticoid inhibitors or IL-1β suppressing protocols to safely elevate baseline energy expenditure and metabolic resilience in older adults.

Context/Source

  • Open Access Paper: Bistable regulation of adipocyte heterogeneity governs thermogenesis, Nov. 11, 2026.
  • Institutions: Beckman Research Institute at City of Hope Medical Center (USA), California Institute of Technology (USA), Wuhan University (China), Marche Polytechnic University (Italy)
  • Country: USA, China, Italy
  • Journal: Nature
  • Impact Evaluation: The impact score of this journal is 64.8, evaluated against a typical high-end range of 0–60+ for top general science, therefore this is a Elite impact journal.

Related Reading:

RapAdmin

Researchers at Singapore Management University and the National University of Singapore ran a preregistered, door-to-door national survey of 2,003 Singapore adults to find out who would take a repurposed chronic-disease drug, framed as a health optimization medication, and why. The answers were sobering for the field. Even told to assume perfect physical and mental health forever, 71 percent wanted to live no more than ninety years and only 8 percent wanted to pass 120. On willingness to take such a medication, 36 percent agreed, 30 percent disagreed, and 32 percent, sat neutral. Structural equation modeling found that one variable dominated everything else: whether people believed the drug would work. Perceived efficacy predicted willingness roughly four times more strongly than perceived risk and ten times more strongly than ethical concerns.

Geroscience has spent two decades building a case that aging is modifiable. Comparatively little attention has gone to the question of whether anybody would actually take the resulting drugs. The assumption running quietly beneath the field is that demand is latent and enormous, waiting only for a compound to clear regulatory approval. This survey tests that assumption in a country that is aging faster than almost anywhere else, and the assumption does not completely hold up.

Most published work on public attitudes toward longevity drugs rests on small convenience samples, often a few hundred mostly female Western respondents recruited online. This study sent trained interviewers to 9,781 addresses across Singapore, sampled postal codes in proportion to population and stratified by housing type and region, and selected within households by whoever had the next birthday. It was preregistered before data collection. The questionnaire ran in all four official languages. That is a substantially more defensible foundation than the field has had.

The first finding is about how long people want to live, and it is clear that people in Singapore have quite modest goals. Respondents were asked to imagine they could maintain optimal physical and mental health forever. Under that framing, which removes every ordinary objection about decline and dependency, 65 percent still chose sixty to ninety years. Another 6 percent wanted sixty or less. Only 2 percent chose 120 to 150 years. An American study using similar framing found nearly 80 percent wanting to live past 120. The gap is enormous and the authors attribute it to culture rather than to health perception, which is consistent with prior work showing Eastern populations desire shorter lives than Western ones.

The second finding concerns the drugs themselves. Opinion split almost evenly three ways. Thirty-six percent said they would want to take a health optimization medication, 30 percent said they would not, and 32 percent declined to take a side.

The third finding is the one that matters for anyone trying to move those numbers. When the researchers modeled willingness against seven theoretically motivated predictors, one of them swamped the rest. Belief that the medication would improve one’s health carried a standardized coefficient of 0.53. The next largest, perceived health risk, came in at negative 0.14. Ethical concerns managed negative 0.05. Worry about chronic disease, 0.06. Whether a person had ambitious life goals, or wanted a long life at all, predicted essentially nothing once efficacy belief was accounted for.

The practical reading is clear. Arguments about whether life extension is natural, fair, or socially sustainable move almost nobody. Evidence that a drug works moves nearly everybody who can be moved.

The authors write that although several relationships reached significance, their practical relevance appears limited, and that the theory they set out to test may not be the right framework. One oddity went in the wrong direction entirely: people who worried more about an overpopulated elderly society were more willing, not less.

Insights

The headline number is that perceived efficacy carried a standardized coefficient of 0.53 toward willingness, in a model explaining 39 percent of the variance. Translated into the actual measurement scale, a one standard deviation rise in belief that a medication would improve your health corresponds to roughly 0.61 points of movement on a five-point willingness scale. By comparison, a one standard deviation rise in perceived health risk moves willingness down only 0.16 points, and ethical concern moves it down 0.06. Efficacy belief is therefore roughly four times more influential than safety concern and about ten times more influential than ethical objection. Squaring the coefficients suggests efficacy belief alone accounts for roughly three quarters of everything the model explains.

Second, don’t assume that people who want to live a long time are the only people in the longevity market. Desired lifespan had no relationship to willingness at all, with a coefficient of negative 0.009 and a p-value of 0.59. The mediation hypothesis connecting life goals to drug willingness through desired lifespan failed outright. Someone’s stated enthusiasm for longevity tells you nothing useful about whether they would take a pill.

Third, note the modal response was neutral at 32 percent. The persuadable middle is larger than either committed camp.

Fourth, 71 percent of respondents wanted ninety years or fewer even with perfect health guaranteed. Messaging built around radical life extension targets roughly 8 percent of this population, surprising as it may be be for people in the longevity enthusiasts group.

Context and Source

  • Open Access Paper: Life aspirations, risk-benefit perceptions, and public acceptance of candidate gerotherapeutic medications: a preregistered national survey in Singapore
  • Institutions: College of Integrative Studies, Singapore Management University; Healthy Longevity Translational Research Programme and NUS Academy for Healthy Longevity, Yong Loo Lin School of Medicine, National University of Singapore; Department of Human Movement Sciences, Vrije Universiteit Amsterdam; EvidencePointSA, Singapore.
    Country: Singapore, with Netherlands collaboration.
  • Journal: Frontiers in Aging (Frontiers Media)
  • Impact evaluation: The impact score of this journal is 4.9, evaluated against a typical high-end range of 0 to 60+ for top general science, therefore this is a Low impact journal.

RapAdmin

Researchers at the Chinese Academy of Sciences took muscle stem cells from a mouse’s own thigh, grew and differentiated them in culture, then injected the resulting myocytes under the skin of the animal’s back. The cells organized into vascularized, mature muscle tissue that contracted spontaneously and survived at least three months. In 18-month-old female mice, these grafts were associated with higher lean mass, roughly 40 percent greater running distance, 16 percent higher grip strength, modestly higher bone density, lower white cell and liver enzyme levels, reduced hepatic senescence staining, better Y-maze performance, and nearly doubled circulating FGF21. Similar metabolic benefits appeared in diet-induced obese mice. The team also engineered grafts to secrete parathyroid hormone or growth hormone, correcting experimental hypoparathyroidism.

Exercise is the closest thing geroscience has to a universal intervention. It improves muscle, bone, metabolism, mood and cognition at once, and it does so partly because contracting muscle is an endocrine organ, releasing a stream of signaling proteins called myokines into the bloodstream. The field has spent two decades trying to bottle this. Most attempts pick one myokine, irisin or BDNF or FGF21, and try to deliver it as a drug. The results have been underwhelming, which suggests that the benefit may lie in the whole secretome rather than any single component.

This paper takes a different route. Instead of delivering a molecule, it delivers the organ.

The procedure is conceptually simple. Take a small biopsy from the animal’s own quadriceps, isolate the muscle stem cells, expand them in culture, push them one step down the differentiation path into myocytes, then inject them under the skin of the back in a gel scaffold. What happens next is the surprising part. The cells do not die, which is what usually happens to transplanted myoblasts. They organize into recognizable muscle tissue with multiple fiber types, recruit a blood supply from the host, and begin contracting. Not in response to a nerve signal, because there is no nerve. They contract on their own, visibly, continuously, for months.

A small patch of muscle twitching under the skin would be a curiosity if nothing else followed. Something else followed. In 18-month-old mice, animals carrying these grafts ran noticeably farther on a treadmill and gripped harder than sham-operated controls. Their lean mass held up better and their fat mass dropped. Bone density was slightly higher. Liver enzymes fell, senescent cells in the liver declined, and the fibrous collagen that accumulates in aging liver was reduced. White blood cell counts and inflammatory gene expression in distant muscle moved toward the levels seen in young animals. In a Y-maze test the grafted mice showed more interest in the novel arm, and fewer degenerating neurons appeared in their hippocampus.

The proposed explanation is endocrine. The graft is a factory. Serum FGF21 nearly doubled, BDNF rose, and the graft tissue itself showed elevated myokine gene expression alongside suppressed inflammatory genes. The authors argue, reasonably, that newly built muscle free of the accumulated damage in old fibers might secrete more effectively than the animal’s own aged tissue.

Then comes the clever extension. Because the graft is built from cultured cells, those cells can be genetically modified before implantation. The team inserted genes for parathyroid hormone and growth hormone. Mice with their parathyroid glands surgically removed, a model of a real human surgical complication, had their blood calcium and phosphate partially corrected by a graft secreting the hormone continuously. That is a different proposition from the anti-aging claim: a living, slow-release hormone depot made from a patient’s own cells.

Two things should restrain enthusiasm. The investigators state plainly that they were not blinded to which mice received grafts, and several of the headline outcomes are exactly the kind that unblinded assessment distorts: how far a mouse runs when prodded, how hard it grips, how long it lingers in a maze arm.

Insights

What the data do offer is a calibration of how large an effect contracting muscle mass can produce. In 18-month-old mice, grafts were associated with 43 percent greater running distance, with a standardized effect size around 1.1, and 16 percent higher grip strength at an effect size near 1.4. For reference, researchers call 0.8 a large effect. Lean mass rose about 5 percent and fat mass fell about 13 percent. These are the magnitudes achievable from adding a small amount of continuously active muscle, and they are in the same range as exercise training studies in aged rodents. The implication, which is actionable, is that the mechanism being exploited here is the same one available free through resistance training and walking. The graft is a substitute for people who cannot exercise, not an upgrade for people who can.

The one biomarker worth noting is FGF21, which nearly doubled at an effect size around 2.2, the largest measured anything in the paper. FGF21 rises with fasting, exercise, and cold exposure, and is the single most plausible mediator of the systemic effects reported.

Treat the hormone-delivery result as the more near-term application. A cell-based depot secreting parathyroid hormone continuously addresses a real clinical problem, post-surgical hypoparathyroidism, better than the anti-aging framing does.

Context and Source

  • Paywalled Paper: Contractile myografts confer systemic anti-aging benefits
  • Institutions: State Key Laboratory of Organ Regeneration and Reconstruction, Institute of Zoology, Chinese Academy of Sciences, Beijing; University of Chinese Academy of Sciences; Beijing Institute for Stem Cell and Regenerative Medicine; National Clinical Research Center for Orthopedics, Sports Medicine and Rehabilitation, Chinese PLA General Hospital, Beijing.
  • Country: China
  • Journal: Nature Aging (Springer Nature)
  • Impact evaluation: The impact score of this journal is 25.0, evaluated against a typical high-end range of 0 to 60+ for top general science, therefore this is a High impact journal.