Here's an uncomfortable truth: most runners run their easy runs too hard. It's perhaps the most common training mistake in distance running, and it's holding you back more than you might realise.

If you've ever finished an "easy" run feeling pleasantly tired rather than genuinely recovered, or if every run feels like it falls somewhere in the middle—not hard, not easy, just... moderate—this one's for you.

What the Best Runners Actually Do

When researchers examined how elite endurance athletes structure their training, they found something surprising. Across disciplines—running, cycling, cross-country skiing, rowing—world-class performers consistently follow a similar pattern: roughly 80% of their training at low intensity, with only about 20% at high intensity ^[1].

This "polarised" or "80/20" approach wasn't invented by coaches or sports scientists. It emerged naturally over decades as athletes and coaches discovered what actually worked. Dr Stephen Seiler, the Norwegian-based researcher who first documented this pattern, found that elite athletes appear to self-organise toward this distribution regardless of their sport, nationality, or coaching philosophy ^[2].

The key insight? Very little training happens in the middle. Elite runners either go genuinely easy or genuinely hard—they avoid the moderate "grey zone" that dominates most recreational runners' training.

Why Easy Running Is So Effective

Easy running isn't wasted time. At low intensities—typically below 75–80% of maximum heart rate—your body develops crucial physiological adaptations that form the foundation for all faster running:

• Mitochondrial development—easy running stimulates the growth of mitochondria, the energy-producing structures within your muscle cells. More mitochondria means greater capacity to generate energy aerobically ^[3].
• Capillary density—low-intensity training promotes the growth of new capillaries around muscle fibres, improving oxygen delivery and waste removal.
• Fat oxidation—at easy paces, your body primarily burns fat for fuel. Regular easy running trains your metabolism to become more efficient at accessing this abundant energy source, sparing precious glycogen for when you really need it ^[4].
• Running economy—the more easy miles you accumulate, the more efficient your movement patterns become. You literally learn to run with less effort.
• Structural adaptation—tendons, ligaments, and bones adapt to running stress over time, but they need lower-intensity training to do so without breaking down.

These adaptations occur best at lower intensities. Push too hard, and you shift the training stimulus away from aerobic development toward glycolytic energy systems—useful for speed, but not what you're trying to build on easy days.

The Moderate Intensity Trap

Here's where most runners go wrong. Instead of polarising their training between genuinely easy and genuinely hard, they end up doing most of their running at a moderate intensity—typically around 80–85% of maximum heart rate. This feels comfortably hard: you're working, but not suffering.

The problem? This "grey zone" training is too hard to allow full recovery but not hard enough to provide the stimulus for top-end fitness gains. You end up in a frustrating middle ground where:

• You're always slightly fatigued, never fully recovered
• Your hard sessions suffer because you're carrying cumulative fatigue
• You plateau because you're not getting enough quality at either end of the intensity spectrum
• Injury risk increases as your body never gets the recovery it needs

Research comparing different training distributions found that polarised training—emphasising both low and high intensity while minimising moderate intensity—produced greater improvements in VO2max, time to exhaustion, and peak power than threshold-focused or high-volume approaches ^[5].

How to Know If You're Going Easy Enough

So what does "easy" actually mean? There are several ways to gauge whether you're in the right zone:

The talk test—on a genuine easy run, you should be able to hold a full conversation without gasping for breath. Not just one-word answers, but complete sentences. If you're running alone, you should be able to speak aloud comfortably. This simple test is surprisingly accurate at identifying the aerobic threshold.

Heart rate—easy running typically falls below 75–80% of your maximum heart rate. For many runners, this means staying below roughly 140–150 beats per minute, though individual variation exists. If you use heart rate zones, Zone 2 is your target.

Perceived effort—on a scale of 1–10, easy running should feel like a 3–4. You should finish feeling like you could have done significantly more. If you're relieved when it's over, you went too hard.

The morning-after test—if your easy run leaves you feeling tired the next day, it wasn't easy enough. True easy running should leave you feeling recovered, not depleted.

Here's the uncomfortable part: for many runners, running genuinely easy feels embarrassingly slow. Your ego takes a hit. You might worry that slower running won't make you faster. But the research is clear: slowing down your easy runs allows you to push harder on your hard days, and it's this contrast that drives improvement.

Fat Burning and the Easy Pace Connection

At easy paces, fat becomes your primary fuel source. This matters for endurance performance because your body stores vastly more energy as fat than as glycogen—even lean runners carry enough fat to fuel dozens of marathons, but only enough glycogen for about 90 minutes of hard running.

Training your body to efficiently oxidise fat at easy paces means you can sustain effort longer before hitting the wall. The process of transporting fatty acids into your mitochondria for burning requires carnitine—a compound that shuttles long-chain fatty acids across the mitochondrial membrane ^[6].

Research suggests that L-Carnitine supplementation may support fat oxidation during exercise and help spare muscle glycogen, potentially contributing to improved endurance capacity ^[7]. RunStrong includes 1000mg of Carnipure® L-Carnitine L-Tartrate—the most research-backed form of L-Carnitine—to support your body's ability to tap into fat as fuel during those crucial easy miles.

Recovery: Where the Magic Happens

Easy running isn't just about what happens during the run—it's about what happens afterwards. Training provides the stimulus; adaptation happens during recovery. And this is where many runners undermine their progress.

Every training session creates some degree of muscle damage and inflammation. This is normal and necessary—it's the signal that triggers adaptation. But if you're constantly running at moderate intensity, you're accumulating more damage than your body can repair between sessions. The result is chronic low-grade inflammation, persistent fatigue, and eventually illness or injury.

Genuine easy running minimises this damage. You still get the aerobic stimulus, but without the muscle trauma that comes with harder efforts. This allows your body to fully recover—and fully adapt—before your next quality session.

Supporting your body's recovery processes matters. Curcumin, the active compound in turmeric, has been shown to help reduce exercise-induced muscle soreness and support recovery after training ^[8]. Research in athletes has found that curcumin supplementation can attenuate inflammatory markers and reduce delayed-onset muscle soreness (DOMS) following exercise ^[9]. RunStrong contains 500mg of Curcumin C3 Complex®—the most studied form of curcumin—enhanced with BioPerine® for improved absorption.

Practical Tips for Slowing Down

If you've spent years running at moderate intensity, slowing down takes deliberate practice. Here's how to make the shift:

1. Use a heart rate monitor
   At least initially, heart rate feedback helps override the urge to push. Set an alert for your upper limit and slow down when it beeps—no exceptions.
2. Run by time, not distance
   When you're trying to run easy, chasing a specific distance encourages pushing. Running for 45 minutes at whatever pace keeps you easy removes that pressure.
3. Leave your watch at home occasionally
   Run purely by feel, using the talk test. Without pace data staring at you, it's easier to embrace slowness.
4. Choose routes with hills
   On hilly terrain, you're forced to adjust pace constantly. Walk the steep uphills if needed—there's no shame in it, and it keeps the effort genuinely easy.
5. Run with a slower partner
   If you have a friend who runs slower than you, join them. You'll be forced to match their pace, and you'll probably enjoy the conversation.
6. Reframe your thinking
   Easy runs aren't about fitness—they're about recovery and consistency. The fitter you get, the more easy running you can absorb, which drives further fitness. It's a virtuous cycle.

Making Hard Days Count

The flip side of running easy is running hard—when it's time to run hard. If you've been running everything at moderate intensity, you might find you've forgotten what truly hard feels like.

With proper recovery from genuinely easy running, your hard sessions become more effective. You arrive fresh, you can push deeper into discomfort, and you generate a stronger training stimulus. Two quality sessions per week—intervals, tempo runs, or race-pace work—is typically sufficient for most recreational runners ^[1].

The contrast between easy and hard is what drives adaptation. Without easy days, you can't go hard enough on hard days. Without hard days, easy running alone won't make you faster. It's the combination that works.

Final Take-Home Points

• 🏃 Most runners go too hard on easy days—if you can't hold a conversation, slow down.
• 📊 Follow the 80/20 principle—roughly 80% of your running should be genuinely easy, with only 20% at higher intensities.
• ⚡ Easy running builds your aerobic engine—mitochondria, capillaries, fat oxidation, and running economy all develop best at lower intensities.
• 🔄 Avoid the grey zone—moderate intensity running is too hard to recover from and not hard enough to make you faster.
• 💪 Support your recovery—RunStrong's combination of Curcumin C3 Complex® and Carnipure® L-Carnitine supports both recovery from training and efficient fat oxidation during easy running.
• 🎯 Make hard days count—arriving fresh at quality sessions means you can push harder and get more from every interval.

Slowing down to speed up feels counterintuitive. But if you're stuck in a plateau, perpetually fatigued, or just not seeing the progress your training volume deserves, running easier might be exactly what you need.

References

1. Seiler S. (2010). What is best practice for training intensity and duration distribution in endurance athletes? International Journal of Sports Physiology and Performance, 5(3), 276–291. https://doi.org/10.1123/ijspp.5.3.276
2. Seiler KS, Kjerland GØ. (2006). Quantifying training intensity distribution in elite endurance athletes: is there evidence for an "optimal" distribution? Scandinavian Journal of Medicine & Science in Sports, 16(1), 49–56. https://doi.org/10.1111/j.1600-0838.2004.00418.x
3. Holloszy JO, Coyle EF. (1984). Adaptations of skeletal muscle to endurance exercise and their metabolic consequences. Journal of Applied Physiology, 56(4), 831–838. https://doi.org/10.1152/jappl.1984.56.4.831
4. Achten J, Jeukendrup AE. (2004). Optimizing fat oxidation through exercise and diet. Nutrition, 20(7-8), 716–727. https://doi.org/10.1016/j.nut.2004.04.005
5. Stöggl T, Sperlich B. (2014). Polarized training has greater impact on key endurance variables than threshold, high intensity, or high volume training. Frontiers in Physiology, 5, 33. https://doi.org/10.3389/fphys.2014.00033
6. Stephens FB, Constantin-Teodosiu D, Greenhaff PL. (2007). New insights concerning the role of carnitine in the regulation of fuel metabolism in skeletal muscle. The Journal of Physiology, 581(2), 431–444. https://doi.org/10.1113/jphysiol.2006.125799
7. Kim JH, et al. (2015). L-Carnitine enhances exercise endurance capacity by promoting muscle oxidative metabolism in mice. Biochemical and Biophysical Research Communications, 464(2), 568–573. https://doi.org/10.1016/j.bbrc.2015.07.009
8. Hewlings SJ, Kalman DS. (2017). Curcumin: A Review of Its Effects on Human Health. Foods, 6(10), 92. https://doi.org/10.3390/foods6100092
9. Nicol LM, et al. (2015). Curcumin supplementation likely attenuates delayed onset muscle soreness (DOMS). European Journal of Applied Physiology, 115(8), 1769–1777. https://doi.org/10.1007/s00421-015-3152-6