--- title: "Your ageing engine is more than your heart" date: 2026-11-08 categories: ["Masters & ageing","Training"] url: https://www.semiprocycling.com/digest/your-ageing-engine-is-more-than-your-heart author: Damian Ruse (SEMIPRO Cycling) --- # Your ageing engine is more than your heart ![](https://buzz.semiprocycling.com/newsletter-images/e5fa05e3-ea21-48d2-b56b-9e6c1974808a/ab7587270725ac05bab6671d2c0633f6414fdf35780ef40f389b29398282466f.jpg) When you think about losing fitness as you get older, where does your mind go? Probably to your heart. It can't beat as fast, so it can't deliver as much oxygen, so you slow down. But getting oxygen to your legs is only part of the job. It still has to reach the working muscle fibres and be used to produce energy. Capelli and colleagues examined that distinction by modelling data from nine earlier papers. Across the ages they compared, the estimated fall in VO₂ max between 20 and 70 was about 46%, while maximal cardiac output fell about 31%. Reduced pumping capacity alone didn't explain the difference. Their analysis points to an increasing limitation in oxygen diffusion and use within muscle as we age. This wasn't a training trial in cyclists. The source populations were mainly moderately active, mostly men, with a trained subgroup and some women included. The model also combines several processes; it can't tell us how much each one contributes. Think about the final part of oxygen's journey. Capillaries bring blood close to muscle fibres. Oxygen crosses into the tissue and reaches mitochondria, where it helps turn fuel into usable energy. The amount of muscle, its blood supply and its capacity to use oxygen all matter. A strong pump doesn't guarantee that everything downstream can keep up. That's the interesting training question: are we giving enough attention to the muscle's ability to receive and use the oxygen we're working so hard to deliver? There is a reason to be hopeful here. Separate research by Mølmen and colleagues found that endurance training, high-intensity training and sprint intervals all increased mitochondrial content. Endurance training produced the largest gains in capillary density. These aren't exclusive adaptations: intervals can affect capillaries too, and steady riding can build mitochondria. Those findings also need context. Capillary gains were observed in untrained to moderately trained participants, and starting fitness influenced the response. An experienced cyclist shouldn't expect the same changes as someone beginning training. But the review found that the capacity to adapt was retained with age. If your goal is to preserve aerobic capacity as you age, this gives you something specific to focus on: the muscle tissue that receives and uses oxygen. Capillary supply and mitochondrial capacity belong in that picture alongside the heart's pumping capacity. It also changes what you look for in a training approach. How does it support those adaptations, and what evidence applies to someone at your current fitness level? Time available affects how you put that into practice. It doesn't change the need to consider both delivery and use. Getting oxygen there is part of fitness. Being able to use it is part of fitness too. **Source.** Capelli C, Ferretti G, di Prampero PE, Tam E. Cardiovascular and peripheral factors affecting the decay of maximal oxygen uptake across the spectrum of age in humans. _European Journal of Applied Physiology_. 2026;126:1635–1643. Published online 29 October 2025. [doi:10.1007/s00421-025-06031-6](https://doi.org/10.1007/s00421-025-06031-6). Training evidence: Mølmen KS, Almquist NW, Skattebo Ø. Effects of Exercise Training on Mitochondrial and Capillary Growth in Human Skeletal Muscle: A Systematic Review and Meta-Regression. _Sports Medicine_. 2025;55:115–144. [doi:10.1007/s40279-024-02120-2](https://doi.org/10.1007/s40279-024-02120-2). OFFICIAL KIT PARTNER Check out the Lameda kit I’ve been riding in here: [https://www.lameda.cc/SEMIPRO](https://www.lameda.cc/SEMIPRO) Use code SEMIPRO for 15% off eligible cycling kit (I earn a commission on eligible purchases). ## On my mind: Getting the flywheel moving We rolled out the Winter Block this week, and it's reminded me how much there is to learn before structured training starts to feel normal. There's the session in front of you. Then there's everything around it: getting set up, understanding what's being asked, working out how to judge your effort. And sometimes there's a test on your second day, before you've really found your feet. That can be a bit scary. What I've seen over and over is that the people who get the most from it are willing to meet that challenge. They give it the best they've got, stay open to learning, and pick themselves up when something doesn't go well. You don't have to get every part right straight away. You do have to give yourself a chance to learn it. Launching a programme with a group like this has made that process more obvious to me. A plan can be sitting there ready to go, but the habits around it still need to get started. You have to work out how it fits into your life, and what to do when a session doesn't go the way you expected. That applies when you're starting structured training, but also when you've ridden for years and decide to change something. Familiarity with riding doesn't make every new approach familiar. So if something felt awkward this week, don't write it off yet. Pick one thing you can do a little better next time, and have another go. It takes a bit of work to get the flywheel moving. — Damian **PS.** Lameda is our official kit partner, and I’ve now put together a full review of the kit I’ve been riding in. I think you’d be surprised at how good some of it is. I went through a long process to work out what you really get and where the compromises are, so you can learn from what I found before buying. [Watch the review here](https://youtu.be/epxIjtSkT7g), then [check out the kit here](https://www.lameda.cc/SEMIPRO). Use code SEMIPRO for 15% off eligible cycling kit (I earn a commission on eligible purchases). Semi-Pro Limited, Suite 1104, 70 Queen's Road, Central, Hong Kong.