Mitochondria and longevity: how they produce your energy, and what wears them out
Every heartbeat, every thought, every step depends on a molecule your cells are constantly manufacturing: ATP. And almost all of this production takes place in tiny structures called mitochondria. Understanding what wears them down—and what truly maintains them—gives you a concrete handle on your energy, both today and twenty years from now.
In brief
Your mitochondria transform nutrients and oxygen into ATP, the form of energy your cells can use. With age, their capacity decreases on average, but part of this decline follows the level of physical activity. Sedentary behavior, chronic excess glucose, sleep debt, prolonged stress, and certain toxins take a toll on them. The best proven lever for supporting them, at any age, remains exercise—notably endurance and interval training. Supplements, meanwhile, are still at the stage of being promising but unconfirmed.
Mitochondria and ATP: the basics
You don't eat energy: you eat fuel that your cells must convert.
ATP (adenosine triphosphate) is a small molecule formed of a base (adenine), a sugar, and three phosphate groups. When the cell detaches the last phosphate, it releases usable energy: to contract a muscle, transmit a nerve impulse, copy DNA, or repair a protein. ATP is not stored in large quantities; it is recycled continuously. Over the course of a day, your body regenerates an amount of ATP roughly equal to your own body weight[17].
1. Glycolysis
In the cytoplasm, glucose is broken down into pyruvate. Fast, oxygen-free, but inefficient: only 2 ATP per glucose molecule.
2. Krebs cycle
Inside the mitochondrion, fuel from sugars, fats, and certain amino acids is oxidized to load electron carriers (NADH, FADH₂).
3. Respiratory chain
On the inner membrane, these electrons circulate to oxygen. The resulting gradient spins the ATP synthase, which produces the bulk of the ATP (about 30 per glucose).
This is why mitochondria are so central: without them, your metabolism would be reduced to glycolysis. But their role goes beyond energy. They participate in cellular signaling, the triggering of programmed cell death (apoptosis), and they are themselves renewed by a selective recycling system: mitophagy[2].
This may surprise you
- Mitochondria possess their own small circular genome, a vestige of their ancient bacterial origin, and you inherited them almost exclusively from your maternal lineage.
- The respiratory chain normally produces reactive oxygen species (ROS). In low doses, these are also useful signals; it is their chronic excess that causes problems[2].
- In a cell culture study, blocking mitochondrial superoxide excess was enough to prevent three pathways of damage linked to high glucose[6].
What changes with age
Mitochondrial decline is real, but it is not a uniform inevitability.
Mitochondrial dysfunction is listed among the "hallmarks of aging" recognized by research, alongside genomic instability or cellular senescence[1]. In humans, a study conducted on 146 people aged 18 to 89 measured an approximately 8% drop in muscle ATP production capacity per decade, parallel to a drop in aerobic capacity[3]. Another observed, in healthy elderly people, a mitochondrial oxidative and phosphorylating activity reduced by about 40% compared to young adults, associated with greater insulin resistance[4].
Nuance
These studies are cross-sectional: they compare age groups without proving that age alone causes the decline. Aerobic capacity closely follows mitochondrial function, and the authors acknowledge that insulin resistance could also contribute to dysfunction rather than the other way around[3]. Likewise, the link between mitochondrial free radicals and aging is more complex than the original theory supposed[2].
What wears them out
Rarely one culprit: rather an accumulation of loads, day after day.
Sedentary lifestyle
Muscle adjusts its mitochondria to demand. In 24 adults, two weeks of leg immobilization reduced the activity of key mitochondrial enzymes, with energy metabolism genes already declining after 48 hours[5].
Chronic excess glucose
Sustained high glucose increases superoxide production by the respiratory chain, a well-established mechanism in diabetes complications[6]. It is the repeated overload, not an isolated sugary meal, that counts.
Sleep debt
Six nights with 4 hours of sleep were enough to significantly deteriorate glucose tolerance in healthy young men[7]. The direct sleep-mitochondria link in humans remains understudied, but the metabolic impact is clear.
Chronic stress
A systematic review identified 23 experimental studies: 19 showed deleterious effects of psychological stress on mitochondria. They were all on animals; human data remains observational[8].
Finally, certain toxins directly target mitochondria. This is well documented for several drugs, and a smaller but growing body of literature concerns environmental pollutants, with vulnerability varying based on genetics, tissue, and developmental stage[9]. To learn more about the role of free radicals, you can read our article on oxidative stress.
What truly supports them
The good news: your mitochondria remain trainable, even after age 65.
When you exert yourself, your muscle activates PGC-1α, a master regulator of new mitochondria production (mitochondrial biogenesis). After a single exercise session, its transcription increases sharply and transiently in human muscle[10]. Repeated week after week, this stimulation results in lasting adaptations.
The benchmark study here is that of Robinson and his colleagues: young (18–30 years) and older adults (65–80 years) followed 12 weeks of high-intensity interval training (HIIT), strength training, or a combination of both. Only HIIT and combined training improved muscle mitochondrial respiration and aerobic capacity, and HIIT reversed several age-related differences in mitochondrial proteins in older people[11]. However, all three programs improved insulin sensitivity and lean mass—hence the advantage of combining both approaches.
Move, often
Endurance and intervals for mitochondria, strength training for the muscle that houses them. In short, the opposite of immobilization.
Sleep enough
Protecting your sleep means protecting your glucose regulation, and therefore limiting repeated metabolic overload[7].
Avoid overload
A diet that avoids chronic caloric excess and repeated glycemic spikes reduces the pressure on the respiratory chain[4][6].
Supplements: where science stands
Emerging or limited evidence: interesting to follow, premature to promise.
Coenzyme Q10
A link in the respiratory chain. Its most solid trial, Q-SYMBIO, involved 420 people with heart failure: fewer major cardiovascular events over two years, but no change in criteria at 16 weeks[12]. These results do not apply to healthy individuals.
NAD⁺ precursors
Nicotinamide riboside does increase blood NAD⁺ in humans[13] and in aged muscle, but without changing mitochondrial bioenergetics after 21 days[14]. More details in our article NAD⁺ and longevity.
Urolithin A
Derived from the transformation of ellagitannins (pomegranate, berries) by the microbiota, it stimulates mitophagy. In elderly humans, it was shown to be safe and modified mitochondrial markers[15].
What Urolithin A did not show
In a four-month trial with 66 people aged 65 to 90, it improved neither walking distance (primary outcome) nor maximum muscle ATP production, despite a gain in muscle endurance[16].
Note
None of these supplements have demonstrated an effect on longevity in healthy humans, nor a benefit comparable to that of exercise. If you are taking medication or living with a health condition, speak to your doctor or pharmacist before trying them.
The Ayurvedic perspective
A traditional framework, not a scientific equivalent.
In the Ayurvedic tradition, agni refers to the "fire" that transforms what you ingest into substance and energy, and ojas refers to the subtle essence that results from proper transformation, associated with vitality and resilience. The texts recommend not overloading agni, eating at regular times, moving every day according to one's constitution, and respecting sleep.
Practical take-away
Agni is not the mitochondrion, and Ayurveda does not describe ATP. But the actions that this tradition values—regularity, daily movement, moderation, rest—align in many respects with what current physiology confirms. Two different languages that can help you stay on track.
Putting your energy in motion
Mitochondria are at the heart of our guide Movement & Energy Metabolism—how to move, recover, and fuel your metabolism to maintain your energy in the service of a longevity that is lived rather than endured.
View the full guideFrequently asked questions about mitochondria
How do I know if my mitochondria are not functioning well?
Fatigue or slow recovery are too non-specific to confirm this: they have many possible causes. Mitochondrial diseases are diagnosed through specialized medical tests. If fatigue persists, consult a healthcare professional.
Is it too late to improve mitochondrial function after age 65?
No. In the study by Robinson and his colleagues, people aged 65 to 80 improved their muscle mitochondrial respiration after 12 weeks of interval training.
Which type of exercise is most effective for mitochondria?
Endurance and interval training most directly stimulate mitochondrial capacity. Strength training complements this by preserving muscle mass. The best program remains the one you can maintain over time.
Do antioxidants protect mitochondria?
ROS produced by mitochondria also play a signaling role. The link between free radicals and aging has proven more complex than expected, and antioxidant supplementation has not been shown to slow down aging.
Should I take CoQ10 or NMN for energy?
Current data do not support recommending them to healthy individuals for energy or longevity. These molecules remain areas of research; speak with a healthcare professional before taking them.
Scientific references
- López-Otín C, Blasco MA, Partridge L, Serrano M, Kroemer G. Hallmarks of aging: An expanding universe. Cell. 2023;186(2):243-278. DOI.
- Sun N, Youle RJ, Finkel T. The mitochondrial basis of aging. Mol Cell. 2016;61(5):654-666. DOI.
- Short KR, Bigelow ML, Kahl J et al. Decline in skeletal muscle mitochondrial function with aging in humans. Proc Natl Acad Sci U S A. 2005;102(15):5618-5623. PubMed.
- Petersen KF, Befroy D, Dufour S et al. Mitochondrial dysfunction in the elderly: possible role in insulin resistance. Science. 2003;300(5622):1140-1142. PubMed.
- Abadi A, Glover EI, Isfort RJ et al. Limb immobilization induces a coordinate down-regulation of mitochondrial and other metabolic pathways in men and women. PLoS One. 2009;4(8):e6518. DOI.
- Nishikawa T, Edelstein D, Du XL et al. Normalizing mitochondrial superoxide production blocks three pathways of hyperglycaemic damage. Nature. 2000;404(6779):787-790. DOI.
- Spiegel K, Leproult R, Van Cauter E. Impact of sleep debt on metabolic and endocrine function. Lancet. 1999;354(9188):1435-1439. PubMed.
- Picard M, McEwen BS. Psychological stress and mitochondria: a systematic review. Psychosom Med. 2018;80(2):141-153. PubMed.
- Meyer JN, Leung MCK, Rooney JP et al. Mitochondria as a target of environmental toxicants. Toxicol Sci. 2013;134(1):1-17. PubMed.
- Pilegaard H, Saltin B, Neufer PD. Exercise induces transient transcriptional activation of the PGC-1α gene in human skeletal muscle. J Physiol. 2003;546(Pt 3):851-858. PubMed.
- Robinson MM, Dasari S, Konopka AR et al. Enhanced protein translation underlies improved metabolic and physical adaptations to different exercise training modes in young and old humans. Cell Metab. 2017;25(3):581-592. PubMed.
- Mortensen SA, Rosenfeldt F, Kumar A et al. The effect of coenzyme Q10 on morbidity and mortality in chronic heart failure: results from Q-SYMBIO: a randomized double-blind trial. JACC Heart Fail. 2014;2(6):641-649. PubMed.
- Martens CR, Denman BA, Mazzo MR et al. Chronic nicotinamide riboside supplementation is well-tolerated and elevates NAD+ in healthy middle-aged and older adults. Nat Commun. 2018;9(1):1286. DOI.
- Elhassan YS, Kluckova K, Fletcher RS et al. Nicotinamide riboside augments the aged human skeletal muscle NAD+ metabolome and induces transcriptomic and anti-inflammatory signatures. Cell Rep. 2019;28(7):1717-1728.e6. PubMed Central.
- Andreux PA, Blanco-Bose W, Ryu D et al. The mitophagy activator urolithin A is safe and induces a molecular signature of improved mitochondrial and cellular health in humans. Nat Metab. 2019;1(6):595-603. DOI.
- Liu S, D'Amico D, Shankland E et al. Effect of urolithin A supplementation on muscle endurance and mitochondrial health in older adults: a randomized clinical trial. JAMA Netw Open. 2022;5(1):e2144279. DOI.
- Buono MJ, Kolkhorst FW. Estimating ATP resynthesis during a marathon run: a method to introduce metabolism. Adv Physiol Educ. 2001;25:70-71. BioNumbers (Harvard).
