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(3) The Ageing Ultrarunner Needs More Protein Than They Realise

/7 min read

The Sport Is Already Masters Running

The typical ultrarunner is not a twenty-something chasing a first hundred-mile buckle. Analysis of major ultramarathon events consistently shows that the 45–49 age group is the largest participant cohort, and that somewhere between 65 and 70 percent of 100-mile finishes have been recorded by runners over 40 since the mid-1990s. Peak performance in these events tends to sit in the late thirties to early forties. The field is, by demographic reality, a masters population. Yet the protein guidance most follow was built from studies on younger adults — a mismatch that has tangible physiological consequences.

Where the Gap Actually Lives

The contemporary benchmark for daily protein intake in endurance athletes is 1.8 g/kg/day, derived from indicator amino acid oxidation studies and synthesised in a 2025 Sports Medicine review by Witard, Hearris, and Morgan. Most endurance athletes are not meeting it. Habitual intake in both male and female endurance populations averages around 1.5 g/kg/day — a shortfall that exists before any age-related consideration enters the picture. A 2016 study by Doering and colleagues found that masters triathletes were already consuming less protein post-exercise than their younger counterparts (approximately 0.3 g/kg versus 0.4 g/kg), and a substantial fraction reported being unaware of current recommendations. The gap is partly a physiology problem and partly a knowledge problem — the knowledge problem is arguably easier to fix.

What Ageing Actually Does to Muscle Remodelling

This is where the argument sharpens for masters athletes specifically. Doering et al. (Medicine and Science in Sports and Exercise, 2016) tracked integrated myofibrillar protein synthesis rates in trained masters triathletes (mean age ~53 years) and younger trained triathletes (mean age ~27) over three consecutive days of intense endurance training. Both groups consumed equivalent protein — roughly 1.6 to 1.7 g/kg/day — yet the masters group showed measurably lower fractional synthetic rates: 1.49 percent per day versus 1.70 percent per day. That difference did not emerge from eating less. It emerged from the muscle's reduced responsiveness even when protein intake was matched — a form of anabolic resistance that persists in well-trained athletes as they age. A study by McKendry and colleagues (Frontiers in Physiology, 2019) compared endurance-trained masters athletes (~69 years, with at least 20 years of training) to untrained older controls and found virtually identical integrated myofibrillar synthesis rates between the groups — suggesting training status alone does not restore age-related losses in remodelling capacity.

The Counterargument Worth Sitting With

Daniel Moore's 2021 review in Sports Medicine makes a compelling case that masters athletes are, in many physiological respects, simply older versions of younger athletes — not ageing sedentary adults. Their muscle phenotype, capillarisation, and anabolic signalling look more like younger trained athletes than like untrained older people. On this view, applying sedentary ageing research to masters endurance athletes overclaims the problem. This argument has real force — but Moore's own review cites the Doering triathlete data showing blunted remodelling even in trained masters — evidence that the "just older athletes" framework has limits specifically in the context of muscle-damaging exercise. Downhill trail running, back-to-back mountain stages, and 100-mile efforts are exactly that kind of exercise. The physiological protection that training provides does not appear to be complete.

What the Evidence Actually Recommends

The Witard 2025 review offers targets that are evidence-grounded and, for most masters athletes, meaningfully above current practice. The baseline is 1.8 g/kg/day on standard training days — but the less obvious finding is that requirements appear higher on recovery days (above 2.0 g/kg/day) and during carbohydrate-restricted training phases (approximately 1.95 g/kg/day). Most athletes assume protein needs peak on hard training days and drop on rest days. The evidence suggests the opposite. After muscle-damaging efforts such as long descents or a hard ultra, the recovery window is precisely when protein delivery matters most. Witard's review points to preliminary evidence supporting 0.5 g/kg per post-exercise feeding to maximise contractile protein synthesis — a target that for a 70 kg runner means 35 grams at the recovery meal, not the ~21 grams typical of masters athletes consuming at the 0.3 g/kg level documented by Doering in 2016. Pre-sleep protein also matters: Trommelen and colleagues (Sports Medicine, 2023) found that both casein and whey protein consumed before sleep increased overnight myofibrillar synthesis rates by 18–35 percent compared to placebo following endurance exercise. The bodybuilder mythology around casein's uniqueness before bed does not hold — both protein sources work.

The biggest practical lever for masters ultrarunners is not a supplement — it is awareness: knowing that the 1.5 g/kg/day many athletes habitually eat falls short of the 1.8 g/kg/day benchmark, and that the sessions most likely to expose that gap — long mountain runs, back-to-back days, the recovery after a race — are precisely the moments where protein delivery should be highest.

Sources

Ultramarathon Demographics

  1. Knechtle, B., et al., "Analysis of participation and performance in athletes by age group in ultramarathons of more than 200 km in length" https://doi.org/10.2147/IJGM.S39518

  2. Zingg, M.A., et al., "Analysis of performance and age of the fastest 100-mile ultra-marathoners worldwide" https://doi.org/10.6061/clinics/2013(05)04

  3. Hoffman, M.D., & Wegelin, J.A., "The Western States 100-Mile Endurance Run: Participation and Performance Trends" https://doi.org/10.1249/MSS.0b013e3181956d3e

Protein Requirements — Endurance Athletes

  1. Witard, O.C., Hearris, M., & Morgan, P.T., "Protein Nutrition for Endurance Athletes: A Metabolic Focus on Promoting Recovery and Training Adaptation" https://doi.org/10.1007/s40279-025-02203-8

  2. Jäger, R., et al., "International Society of Sports Nutrition Position Stand: Protein and Exercise" https://doi.org/10.1186/s12970-017-0177-8

  3. Thomas, D.T., Erdman, K.A., & Burke, L.M., "Position of the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine: Nutrition and Athletic Performance" https://doi.org/10.1016/j.jand.2015.12.006

  4. Wardenaar, F.C., et al., "Nutrient Intake by Ultramarathon Runners: Can They Meet Recommendations?" https://doi.org/10.1123/ijsnem.2014-0199

Masters Athlete Physiology

  1. Doering, T.M., et al., "Lower Integrated Muscle Protein Synthesis in Masters Compared with Younger Athletes" https://doi.org/10.1249/MSS.0000000000000935

  2. Doering, T.M., et al., "The effect of higher than recommended protein feedings post-exercise on recovery following downhill running in masters triathletes" https://doi.org/10.1123/ijsnem.2015-0221

  3. Doering, T.M., et al., "Comparison of Post-Exercise Nutrition Knowledge and Post-Exercise Carbohydrate and Protein Intake Between Australian Masters and Younger Triathletes" https://doi.org/10.1123/ijsnem.2015-0223

  4. McKendry, J., et al., "Comparable Rates of Integrated Myofibrillar Protein Synthesis Between Endurance-Trained Master Athletes and Untrained Older Individuals" https://doi.org/10.3389/fphys.2019.01084

  5. Moore, D.R., "Protein Requirements for Master Athletes: Just Older Versions of Their Younger Selves" https://doi.org/10.1007/s40279-021-01510-0

  6. Pérez-Castillo, I.M., et al., "Age-Related Anabolic Resistance: Nutritional and Exercise Strategies, and Potential Relevance to Life-Long Exercisers" https://doi.org/10.3390/nu17223503

  7. Doering, T.M., et al., "Postexercise Dietary Protein Strategies to Maximize Skeletal Muscle Repair and Remodeling in Masters Endurance Athletes: A Review" https://doi.org/10.1123/ijsnem.2015-0102

Anabolic Resistance

  1. Wall, B.T., et al., "Aging Is Accompanied by a Blunted Muscle Protein Synthetic Response to Protein Ingestion" https://doi.org/10.1371/journal.pone.0140903

  2. Durham, W.J., et al., "Age-related anabolic resistance after endurance-type exercise in healthy humans" https://doi.org/10.1096/fj.09-150177

  3. Witard, O.C., et al., "Myofibrillar muscle protein synthesis rates subsequent to a meal in response to increasing doses of whey protein at rest and after resistance exercise" https://doi.org/10.3945/ajcn.112.055517

  4. Yang, Y., et al., "Resistance exercise enhances myofibrillar protein synthesis with graded intakes of whey protein in older men" https://doi.org/10.1017/S0007114511003412

Pre-Sleep Protein and Distribution

  1. Trommelen, J., et al., "Pre-sleep Protein Ingestion Increases Mitochondrial Protein Synthesis Rates During Overnight Recovery from Endurance-Type Exercise" https://doi.org/10.1007/s40279-023-01822-7

  2. Trommelen, J., et al., "The anabolic response to protein ingestion during recovery from exercise has no upper limit in magnitude and duration in vivo in humans" https://doi.org/10.1016/j.xcrm.2023.101324

  3. Reis, C.E.G., et al., "Effects of pre-sleep protein consumption on muscle-related outcomes" https://doi.org/10.1016/j.jsams.2020.06.010

Masters Athletes — Nutrition Intake

  1. Guo, S., et al., "Dietary Intake of Masters Athletes: A Systematic Review" https://doi.org/10.3390/nu15234973

  2. Methenitis, S., et al., "The importance of protein intake in master marathon runners" https://doi.org/10.1016/j.nut.2021.111154

Leucine and Dose-Response

  1. Szwiega, S., et al., "Dietary leucine requirement of older men and women is higher than current recommendations" https://doi.org/10.1093/ajcn/nqaa258

  2. Pinckaers, P.J.M., et al., "Dose-response effects of dietary protein on muscle protein synthesis during recovery from endurance exercise in young men" https://doi.org/10.1093/ajcn/nqaa073

Applied Reference

  1. Moore, D.R., "Protein Requirements of Master Athletes" (Gatorade Sports Science Institute) https://www.gssiweb.org/expert-panel/sports-medicine-publications/article/protein-requirements-for-master-athletes-just-older-versions-of-their-younger-selves