Exercise and muscle

30 papers in the library, strongest Strong.

Graded Strong · A large trial assigned 2,111 older adults at random to two programs for two years; there was no group without a program, and participants knew their group.

Papers 30

Coached Lifestyle Program Slows Frailty More Than Going SoloStrongn = 2,1112026The journals of gerontology. Series A, Biological sciences and medical sciencesOlder adults who joined a lifestyle program with regular meetings and coaching became less frail over two years than those who followed a do-it-yourself version. Both groups improved. But the coached group improved more than twice as much. Everyone was 60 to 79, mentally healthy, and at higher risk of faster mental decline. In the US POINTER trial, 2,111 people at five sites were assigned to a group at random. The coached group met 38 times over two years. They did endurance, strength and flexibility training, followed a set eating plan and practiced thinking skills online each week. The other group got information leaflets, six meetings and encouragement, but no goal-based coaching. The researchers tracked a frailty score built from 31 health features. The advantage looked similar in women and men, younger and older people, and those with or without diabetes. There was no group that got no program at all. So the study cannot say how much either program helps compared with doing nothing. Participants also knew which group they were in, and some measures relied on their own reports. Whether the benefit lasts is still being followed.
Time-Restricted Eating Adds No Lean Mass to Strength TrainingModeraten = 1202026Anais da Academia Brasileira de CienciasEating only within a set window each day has become popular for shaping the body. For people who also lift weights, though, the eating window does not appear to add extra fat-free mass, which is mostly muscle. That is the result of an analysis that pooled five trials. By the end of the programs, fat-free mass was similar in both groups. In all five trials, chance decided who ate within a time window and who ate normally. Together they included 120 healthy adults, all doing strength training. On paper, the eating-window group ended up with just under half a kilogram less fat-free mass on average. That figure was so uncertain, however, that no clear difference could be detected. For body weight and fat mass, only two of the five trials found a clear difference. The researchers had expected the eating window to increase fat-free mass, and that idea was not confirmed. With only 120 participants, smaller differences could still go unnoticed. At the same time, this small analysis did not show a clear loss of fat-free mass from the eating window either.
Creatine Adds a Small Strength Gain to Training After 60Moderaten = 112026Frontiers in nutritionOlder adults who took creatine alongside strength training gained a little more strength than those who trained alone. The extra gain was small, but it showed up clearly in the pooled data. That matters later in life, because low muscle strength is seen as the key sign of possible age-related muscle loss. The researchers pooled eleven trials. In each one, chance decided who got creatine and who got a dummy supplement. Everyone was 60 or older, about 67 on average, and mostly healthy. Both groups followed the same training program. A common dose was 5 grams a day for 12 to 14 weeks. Neither the dose, the length of training nor sex reliably explained differences between the trials. For muscle mass and physical performance, no clear difference was detected, and the evidence there is thin. Six of the eleven trials also had a lot of missing measurements. Frail people and those who had already lost muscle were barely included, so the results cannot simply be applied to them.
Creatine After 45: More Strength Even Without TrainingModeraten = 732026Journal of the International Society of Sports NutritionAdults aged 45 to 65 who had barely exercised took creatine for twelve weeks. Even without training, they gained lean mass, meaning mostly muscle. After twelve weeks the gain averaged about 1.1 kilograms, with wide uncertainty. They also got stronger on the bench press and the leg press than people taking a dummy powder. The study enrolled 73 healthy, inactive adults. Each first chose whether to join a program of exercise and a weight-loss diet. Then chance decided who took 5 grams of creatine twice a day and who got an identical-looking dummy powder. The exercise group did supervised strength and endurance training three times a week. In the end, 64 people finished. With exercise and diet, creatine also added lean mass and strength, and body fat percentage fell further. Memory tests showed only scattered gains, which the researchers call preliminary. Creatinine, a blood value used to check the kidneys, rose slightly. Side effects were rare and similar across groups. The main limit: the four groups ended with only 13 to 20 people each, and exercise was chosen, not assigned by chance.
Strength per Unit of Muscle: Resistance Training Stands OutModeraten = 3,1412026Ageing research reviewsToo little strength for the amount of muscle a person has is seen as a core feature of age-related muscle loss. An analysis that pooled 41 trials found that resistance training improved this measure in people aged 60 and older. For aerobic exercise, combined programs and nutritional supplements, no clear improvement was detected. The researchers pooled trials with 3,141 older adults in total. In every trial, people were chosen at random for a program or a comparison group. Each program lasted at least eight weeks. The trials measured muscle strength divided by muscle mass. Approaches included resistance training, aerobic exercise, both together, exercise plus supplements, supplements alone and eating fewer calories. Results varied widely between trials, including for resistance training. So the true size of the effect is uncertain. No clear benefit does not mean aerobic exercise or supplements do nothing; the data are not enough to judge. The authors consider resistance training the most effective approach and call for more well-designed trials.
Tai Chi, Dance or Walking: Aerobic Exercise Helps Frail SeniorsModeraten = 4,0112026Clinical nutrition (Edinburgh, Scotland)Older adults who are frail, or heading that way, benefit from aerobic exercise. Those who trained became less frail, got up from a chair more easily and felt less low. The clearest gains were in thinking skills and quality of life. And the type of movement did not seem to matter much. Researchers pooled 44 studies with 4,011 people aged 60 and over. In every study, chance decided who exercised and who received usual care. Because the programs varied so widely, the team converted time and effort into one shared unit, roughly the energy spent per week. Tai Chi, dancing and walking led to similar improvements. No single type stood out as clearly better. The ideal amount of exercise is still open. The studies differed a lot, and few of them tested larger amounts of training. The authors conclude that starting with manageable low to moderate amounts makes sense. In their view, training should fit each person's tolerance, preferences and health.
Sarcopenia: Exercise Speeds Up Standing, Walking and SittingModeraten = 202026Journal of the American Medical Directors AssociationStand up from a chair, walk a short distance, turn around and sit back down. This simple test measures balance and everyday mobility. Older adults with age-related muscle loss got through it faster after an exercise program. On average they were about one and a half seconds quicker than comparison groups. The result comes from an analysis that pooled 20 trials in which people were chosen at random to exercise or not. The team searched five major medical databases to find them. Some groups showed somewhat larger gains. These included strength training, light effort, three or fewer sessions a week and training without supervision. People aged 75 or older also improved more. The authors say this supports using exercise in clinical care. Still, results varied considerably from trial to trial. The subgroups were also not tested head to head. So the analysis cannot show that light, unsupervised exercise works better than harder training.
Drop Sets vs. Rest-Pause: No Clear Winner in the GymModeraten = 232026Scandinavian journal of medicine & science in sportsGym-goers who want to push harder often use one of two tricks. With a drop set, you lower the weight after a tough set and keep going. With rest-pause, you rest for a moment, then carry on with the same weight. In a small head-to-head comparison, both groups got stronger over eight weeks, with no clear difference between the methods. Researchers assigned 23 adults aged 18 to 35 at random to one method. All had at least a year of strength training behind them. They trained twice a week under supervision and followed a set eating plan. Afterwards, the drop-set group could bench press 12.3 kilograms more on average, the rest-pause group 9.5 kilograms. Muscle and other fat-free tissue grew by just over a kilogram in both groups. Fat mass barely changed. The groups were very small, so smaller differences, for example in the bench press, may have gone undetected. There was no group that skipped training. Almost everyone was a young man; only three women took part. Whether the results hold for women, older adults or over longer periods is open.
Aerobic Exercise: 14 of 16 Trials Report Gains in ThinkingModeraten = 162026Frontiers in aging neuroscienceFourteen out of 16 trials pointed the same way. Older adults who did aerobic exercise scored better on thinking tests afterwards than comparison groups. Most participants had mild cognitive impairment, meaning early problems with memory or thinking. The authors describe this kind of mental frailty in later life as a condition that may be reversible. The researchers searched for trials in which chance decided who exercised. Programs ranged from plain aerobic training to Tai Chi, the Chinese Baduanjin routine or kayak paddling, and to exercise done while solving a mental task. All plain aerobic trials and both dual-task trials found improvements. Only the one trial where people exercised first and practised thinking skills separately later found no clear benefit for thinking. The review cannot say how big the benefit is. It simply counted whether each trial found an improvement. Most trials followed people for six months or less, so any effect on dementia risk is unknown. None of the trials measured physical frailty with validated tests.
Muscle Loss in Old Age: Exercise Builds Strength and MassModeraten = 6,2042026Scientific reportsOlder adults with age-related muscle loss get stronger and physically more capable when they exercise. Their muscle mass grows a little too. Doctors call this muscle loss sarcopenia: muscles lose mass and strength with age. That raises the risk of falls, of needing care and of dying early. A research team analysed 72 trials with 6,204 older adults in total. In every trial, chance decided who exercised. Programs lasted from three weeks to three years and ranged from weight training to aerobic exercise and Tai Chi. People who combined exercise with nutritional supplements gained more muscle mass and strength than those on supplements alone. Weight training built more muscle mass than aerobic training, but only two small trials compared them directly. Quality of life showed no clear difference. Whether exercise helps people live longer cannot be said, because only one trial counted deaths. The authors rate their confidence in the main findings as moderate. For comparisons between exercise types and combinations, it is low to very low. Of the trials, 49 did not report side effects.
People Who Became Active Later Had Less Muscle Loss in Old AgeModeraten = 4,7022026BMC geriatricsThe more often people got enough exercise across their adult years, the less often they had age-related muscle loss in later life. It was rarest among those who were active at all three check-ins over the decades. But people who only became active over the years also had muscle loss less often than those who stayed inactive. People who stopped being active showed no clear advantage. The data come from Norway's HUNT study. It included 4,702 people with an average age of 76. Between 1984 and 2008, they reported three times how much they moved. Active meant meeting the World Health Organization advice: at least 150 minutes of moderate or 75 minutes of vigorous activity a week. In 2017 to 2019, researchers measured strength and muscle mass. Muscle loss counted as confirmed when both were low. The link was stronger for confirmed muscle loss than for low strength alone. Exercise was self-reported, not measured. The link could also run the other way: people already losing muscle may have moved less. And almost 3,000 people were left out for missing data, and they were older and weaker.
Exercise Strengthens Grip and Gait in Women After MenopauseModeraten = 7442026Frontiers in public healthAge-related muscle loss is common in women after menopause, partly because of hormonal changes. An analysis that pooled 17 trials found that structured exercise helped women who had it. They gripped harder, walked faster and balanced longer on one leg. The clearest gain came in an everyday test: getting up from a chair, walking a few meters, turning and sitting back down. The trials included 744 women with muscle loss in total. In each one, chance decided who exercised. Most programs ran two to three times a week for 6 to 24 weeks. They used elastic bands, kettlebells or Tai Chi combined with strength work. Comparison groups kept their usual routine or did other activity such as dancing or walking. One measure of muscle mass rose slightly, while a second showed no clear difference. Body fat dropped a little, and BMI showed no clear change. The trials were small and differed a lot. Muscle mass was mostly measured with a weak electric current, much like a body fat scale. Only three trials checked whether the gains lasted after training stopped.
Exercise Lowers Only One of Three Inflammation Markers in Old AgeModeraten = 1,2972026Frontiers in immunologyToo many inflammation signals in the blood weaken muscle strength. They are also linked to how muscle loss and frailty develop and worsen in old age. A new analysis of exercise studies found that in older adults with these problems, training lowered one such signal: TNF-alpha, a messenger that drives inflammation. Two other common inflammation markers in the blood, interleukin-6 and C-reactive protein (CRP), showed no clear change. The researchers pooled 26 trials with 1,297 older adults who had age-related muscle loss, frailty or both. In every trial, chance decided who exercised. The exercise groups did endurance training, strength training or both for at least four weeks. The comparison groups got things like health education or usual care. TNF-alpha fell clearly in people with muscle loss, while no clear difference was detected in frail people. The evidence has limits. Only three of the 21 included publications were rated at low risk of bias, meaning built in ways that keep errors out. Whether the effect lasts is unknown, because none of the trials collected long-term follow-up data.
Active Older Adults With Daily Limits Face Lower Death RiskModeraten = 64,1462026iScienceLosing muscle in later life, or struggling with everyday tasks, comes with a higher risk of dying. But among people who were regularly active in their free time, that extra risk was smaller. This is what an analysis of three large aging surveys from the US, Europe and China found. The analysis covered 64,146 people. Regularly active meant meeting the World Health Organization's advice, about 150 minutes of moderate activity a week. In the US survey, inactive people who struggled with basic daily tasks had an 82 percent higher risk of dying than inactive people without such problems. Among regularly active people, the increase was 39 percent. For age-related muscle loss, the gap between the groups was smaller. Europe and China showed the same pattern. These are observational data. They do not show that activity lowers the risk, because active people may differ in other ways too. It is also unclear which kind of activity matters, since endurance and strength training were not looked at separately.
Too Much Fat, Too Little Muscle: Exercise Helps Older AdultsModeraten = 9172026MaturitasSome older adults carry too much body fat while losing muscle at the same time. Doctors call this sarcopenic obesity. An analysis of 20 trials in this group found that people who exercised lost body fat and gained a little muscle in their arms and legs. Their grip got stronger and they walked faster. The researchers pooled trials with 917 people in total, whose average age ranged from 64 to 81. In each trial, chance decided who exercised. On average, body fat percentage fell by about 2.6 points. LDL cholesterol also dropped slightly. Trials of pure strength training mainly showed more muscle and more strength. Programs that mixed several kinds of exercise also lowered BMI and improved walking speed. The authors stay cautious. They rate the evidence for body shape and strength as only moderately certain. For metabolic measures such as cholesterol, they see weak evidence of very small effects. Which type of exercise suits this group best is not yet clear. The authors say better trials are needed to answer that.
Women 65 and Older Gain Muscle With Training Plus Amino AcidsModeraten = 962026Journal of the International Society of Sports NutritionOlder women who did strength training for three months and also drank protein building blocks gained estimated muscle mass. They also scored better on a fitness test designed for older adults. The researchers conclude that the combination worked better than either training or the drink alone. The study in South Korea enrolled 96 healthy women aged 65 or older, about 73 on average. They were split at random into four groups: no change, training, amino acids, or both. Training was a one-hour circuit three times a week, first with resistance bands, later with kettlebells. Essential amino acids are protein building blocks the body cannot make itself. Women took 5.5 grams in water twice a day. In both training groups, blood levels of myostatin, a protein that brakes muscle growth, went down. An inflammation marker called TNF-alpha fell only in the group that did both. Muscle mass was estimated with a weak electrical current. This method captures all fat-free tissue and is affected by hydration. Twenty of the 96 women dropped out, and diet was not fully controlled. Whether the combination slows age-related muscle loss in the long run cannot be told from 12 weeks in women who were already fit.
Frail From 45: Risk of Death More Than Three Times HigherModeraten = 2,1042026The Journal of frailty & agingFrailty in midlife carries a heavy risk. In a South Korean study of people aged 45 and older, those who were frail had more than three times the risk of dying compared with robust participants. People who were somewhat frail, a stage researchers call pre-frail, had a 72 percent higher risk. The researchers used data from 2,104 adults who were interviewed again and again between 2006 and 2022. Frailty was scored from 38 health features. Frail people also saw doctors more often, were admitted to hospital more often and stayed longer. Their care cost more. Participants reported themselves whether they met the World Health Organization goal of at least 150 minutes of activity a week. Among pre-frail and frail people, meeting that goal was not clearly linked to a lower risk of death once other factors were taken into account. Frail people who reported that much activity even had higher healthcare costs. The authors conclude that standard activity advice alone may not be enough for this group. Activity was self-reported, though, and an observational study like this cannot tell cause from effect.
Vitamin K2 Does Not Speed Muscle Recovery After Weight TrainingModeraten = 802026Medicine and science in sports and exerciseSore, weak muscles can linger for days after a tough strength session. Vitamin K2 has been suggested as a way to recover faster. In this trial it made no measurable difference: strength, everyday movement, soreness and inflammation markers in the blood recovered the same with or without it. The volunteers were healthy adults aged 18 to 40 and adults aged 65 or older. They were chosen at random to take either 240 micrograms of vitamin K2 or a dummy pill every day for 12 weeks. Of 80 people, 71 finished. Before and after the 12 weeks, everyone did an exercise designed to strain the thigh muscles. The team then tracked strength, soreness and blood values for three days. Vitamin K2 levels in the blood rose clearly. Only in the older group did small differences appear. Signals between nerve and muscle ran slightly faster, and a blood marker of muscle damage was lower after three days. The authors see these as leads for future research. Whether the vitamin helps frail older people is unclear, because the older adults here were very healthy.
Lifting After 60 Builds Strength, Muscle Gains Less ClearModeraten = 8012026Sports medicine and health scienceResistance training makes people aged 60 and over stronger. That is the result of an analysis that pooled 16 studies with 801 participants, whose average age was almost 73. Those who trained got clearly stronger and did better in tests of physical performance. For muscle mass, however, there was no clear difference compared with people who did not train. In 15 of the studies, participants were chosen at random to train or not. The programs lasted 10 to 48 weeks. The researchers also looked at speed. Some groups lifted the weight as fast as they could, others deliberately more slowly. In subgroup analyses, the slower pace went along with more strength and muscle mass, the fast pace with better physical performance. These speed comparisons need caution. Speed was not measured with devices but set as a number of seconds per movement. The studies were of moderate quality. For strength gains, the picture may also be skewed by unpublished studies. The analysis reports no side effects.
Strength vs. Endurance: Each Reshapes the Nerve-Muscle LinkPreliminary2026NeuroscienceWhere a nerve meets a muscle, there is a tiny relay point. This is where the nerve tells the muscle to contract. The connection is not a fixed wire, because it rebuilds itself depending on how it is used. A review describes how different kinds of exercise leave distinct marks on it. Endurance training mainly boosts energy supply and helps the junction resist fatigue. Strength training reinforces the spots where the nerve releases its messengers and the receiving side in the muscle. The authors pulled together lab experiments, imaging of living tissue, computer models and human exercise studies. In their reading, interval training combines elements of both. Electrical muscle stimulation can keep signals flowing when someone can barely move on their own. Helper cells around the junction and the surrounding support tissue also play an active role. Exercise appears to supply the energy and building blocks for constant rebuilding, partly through the cell's power plants. This points to exercise helping to keep the nerve-muscle link intact with age. The authors name a clear limit themselves: the evidence is strongest for structural changes. Which training works best for whom still needs studies in people.
Weight Training: Fast Muscle Fibers Change the MostPreliminaryn = 242026Nature communicationsAfter eight weeks of strength training, the biggest changes showed up in fast muscle fibers, in women and men alike. In these fibers, the amounts of 164 proteins shifted in women and 101 in men. In slow fibers, only 9 and 7 changed. Women also showed more remodeling of an inner scaffold of thread-like proteins inside muscle cells. Twenty-four women and men who had not done strength training before trained three times a week with supervision. They did leg presses and leg extensions, three sets of 8 to 12 reps until they could not do another. Researchers took small thigh muscle samples before and three days after the last session. Afterwards, everyone was stronger and had more lean mass in the legs, mostly muscle. One protein, CSRP3, rose specifically in fast fibers. Mice made to produce more CSRP3 in one leg had 4 and 6 percent heavier muscles there than in the other leg. This points to a role for CSRP3 in muscle growth. The authors note that the mouse test does not explain how it works. The human part also had no comparison group that skipped training.
Why Muscle Strength Belongs in Health PolicyPreliminary2026Frontiers in public healthHow strong your muscles are says something about your risk of dying, no matter how active you are. That is the core argument of an opinion piece calling for muscle health to become its own goal in public health policy. The biggest gains, it says, come from strength training or mixed programs, not from aerobic exercise alone. As evidence, the author points to large trials where people were assigned at random. In the LIFE trial, 1,635 inactive adults aged 70 to 89 did walking, strength and flexibility training for 2.6 years on average. Serious walking problems struck 30.1 percent of them, compared with 35.5 percent in a group that got health education. In the SPRINTT trial of 1,519 frail adults aged 70 or older, walking disability became less common only among those who scored poorly on a physical test at the start. This is a viewpoint, not a systematic review: the studies were picked to support the argument. Most exercise trials on age-related muscle loss also last only about 12 weeks. Direct data on whether such programs pay off financially remain sparse.
Standing on One Leg: Fitter Older Adults Died Less OftenPreliminaryn = 13,4232026JAMA network openA few simple tests that take minutes can say a lot about how fit someone over 65 is. In Taiwan, those same tests were closely linked to who survived the next seven years. Balance, leg strength and stamina mattered most. Researchers looked at 13,423 people aged 65 or older who lived at home. In 2015 and 2016 they did seven exercises. They stepped in place for two minutes and stood up from a chair as often as they could in 30 seconds. They balanced on one leg, and they got up, walked a short distance and sat back down. By the end of 2022, 1,631 had died, about one in eight. The top fifth on the get-up-and-walk test had a 59 percent lower risk of death than the bottom fifth. That held after accounting for age, existing illnesses and how active people said they were. The study cannot show that fitness itself extends life. People who were already ill may simply have scored lower. Smoking was not recorded, and fitness was measured only once. The volunteers also leaned healthier, since everyone had to be able to do the tests.
Muscle Age Clocks: Younger After NR, Partly Older After HIITPreliminaryn = 1062026Aging cellNicotinamide riboside, or NR, is a building block of vitamin B3. Like hard interval training, it has been proposed as a way to support aging muscles. In muscle, though, the two pointed in opposite directions. After five months of NR, several epigenetic clocks read younger. After four to six weeks of interval training, some clocks ran faster. Epigenetic clocks estimate biological age from chemical tags on our DNA. The researchers looked at muscle samples from three studies. In one, 30 adult twins aged 30 to 65 took NR, ending at 1,000 milligrams a day. In two others, 39 and 37 people did short, hard intervals three times a week. After NR, three of seven clocks went down, while one went up. After training, the clock that estimates the pace of aging rose in both studies. Another clock fell in the six-week study. None of the studies compared people with a group on a dummy pill, and the groups were small. The researchers measured clocks, not muscle strength or health. Whether NR actually keeps muscles young cannot be read from this. In muscle cells grown in the lab, NR made no clear difference to the clocks.
Older Women Who Trained Saw an Inflammation Signal DropPreliminary2026Journal of sport and health scienceOlder women who exercised regularly for 48 weeks became stronger, more mobile and better at endurance tasks. Over the same period, an immune messenger in their blood called CXCL2 fell sharply, along with a second inflammation marker. In the group that did not exercise, physical performance declined and these inflammation levels rose. The researchers first spotted CXCL2 in public data on gene activity. In older adults, blood levels were higher the more severe their age-related muscle loss. Higher levels also tracked closely with poorer physical performance. In experiments with mice and cells, the messenger rose when muscles wasted or were injured. A single bout of endurance running turned it down. When the team blocked the docking site for CXCL2 in the lab, signals of muscle breakdown weakened. This points to CXCL2 as one link between aging and muscle loss. Whether lowering CXCL2 itself slows muscle loss in people was not tested, because the blocking was done only in the lab. The abstract also does not say how many people took part or whether groups were chosen at random.
Fit Older Adults Have Muscles With a Younger Gene PatternPreliminary2026Nature agingIn older people's muscle, genes that help cells make energy are less active. That holds even next to young adults who are similarly active. In trained older adults, though, half of these age-related differences were missing. On this measure, their muscle looked more like that of young adults. Researchers took small muscle samples from young and older adults with different fitness levels. They measured which genes were switched on, plus fats and other metabolism products in the muscle. They did this before and after a single moderate workout below maximum effort. Everyone responded with immune and stress signals. Among the older adults, the fitter they were, the stronger this response. The data also linked the cells' power plants to fat metabolism and to NAD+, a helper molecule in energy production. The authors read this as sustained training reshaping age-related patterns in muscle. But the study cannot show that training itself caused the gap: the groups were compared once, not followed over years. It also measured gene activity and metabolism products, not strength or health.
In Mice, Muscle Power Plants Need Just Enough SplittingPreliminary2026CellsMitochondria, the tiny power plants inside our cells, constantly split apart and fuse again. In muscle, a protein called Drp1 handles the splitting, cutting the power plants in two. A review of earlier studies describes a balancing act: both too little and too much Drp1 leave muscles shrunken and working poorly. Most of the evidence comes from animals. In mice whose Drp1 was turned down by roughly 60 to 70 percent, muscles lost 40 to 50 percent of their mass within four months. Mice on a very fatty diet showed the opposite problem, a stronger switch-on signal on Drp1. Ten weeks of high-intensity interval training cut that diet-driven rise by just over a third. In people with type 2 diabetes who were chosen at random for aerobic training, the same signal dropped. In old rats, 12 weeks of exercise raised Drp1 levels. From this, the authors propose a model: exercise reins in excess splitting in metabolic disease and boosts weak splitting in old age. That remains an idea, not a proof. The paper pools earlier work without new data, and the authors say parts of their model rest on correlations without direct evidence of cause and effect.
Mice Lacking One Muscle Enzyme Get No Boost From ExercisePreliminaryn = 382026Science advancesWorking muscles produce reactive oxygen molecules. An enzyme called NOX4 makes such molecules, and in doing so it switches on a protective program in the cell, run by a master switch called NFE2L2. Old mice and older men had less NOX4 protein in their muscles. When mice lacked the enzyme only in muscle, their bodies declined much faster with age. The mice ate a normal diet for 20 months. Without muscle NOX4 they became frailer and gained more fat. They had higher inflammation markers in the blood, responded poorly to insulin and developed an inflamed fatty liver. In 12-month-old mice, exercise training raised NOX4 back to the level of young animals. Without NOX4, the training gains did not appear. Restoring NOX4 with a virus, or giving sulforaphane for four weeks, corrected much of the damage. Sulforaphane is a plant compound that turns on the protective program. Liver scarring did not improve. The human side rests on muscle samples from 18 men aged 65 to 71 and 20 young men. In the older men, the protective program was less active. Whether sulforaphane helps older people was not tested: the treatments were tried only in mice.
Lactate From Exercise: Review Weighs Its Role in AgingPreliminary2026Ageing research reviewsDuring exercise, muscles produce a lot of lactate, often called lactic acid. It spreads through the blood to the whole body. A review describes how lactate might act as a signal that links a short workout to lasting changes. At the center is a process called lactylation. A small piece made from lactate gets attached to proteins, and this is linked to how genes are switched on and off. The authors summarize research on four processes. These are quality control of the cell's power plants, balance in the immune system, renewal through stem cells, and inflammatory substances released by aged cells. They look at the brain, the heart and blood vessels, muscles and bones, and metabolism. Using a three-level scale, they rate how strong the evidence is for each process. The evidence differs in strength from one process to the next, and the authors point to key gaps in showing cause and effect. So it is not established that exercise slows aging through lactate. The paper sorts existing research; it is not a new study in people.
Ten Weeks of Training Make Old Mice Less FrailPreliminaryn = 612026Proceedings of the National Academy of Sciences of the United States of AmericaLosing muscle strength in later life makes people frail and erodes quality of life. In old mice, exercise pushed back against this decline. The key seemed to be the mitochondria, the power plants inside muscle cells. These stayed adaptable even in old age. The researchers trained 20-month-old mice five days a week for ten weeks. The animals climbed ladders, balanced on a rotating rod and ran intervals on a treadmill. Afterward they performed as well as a mouse strain bred through a gene change to age especially well. They were less frail, and their muscles held more mitochondria. In mice whose muscle power plants were genetically impaired, training brought no gain in performance. The team also studied muscle samples from 30 people aged 17 to 99 who were having surgery. Older people in poor physical shape had fewer and weaker mitochondria than older people in good shape. These human data come from a single snapshot of a small group. Whether exercise reduces frailty in older people through their mitochondria was not tested in humans.

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