The Science of Why Consistency Creates Fitness (Even 10 Minutes at a Time)
There are 4 physiological reasons why consistent runs have an oversized effect on long-term growth. On a tough day, even 10 or 20 minutes can be plenty to spur progress.
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In 2006, a few months after quitting football in college, I went for the first endurance run of my adult life. I had big dreams! During that downtime between sports, I read training books and message boards, planning my next athletic steps. It was like “The Decision” by LeBron James when he announced he was taking his talents to South Beach–I was going to take whatever talents I had to running.
Maybe I’d walk onto the track team. Maybe I’d win some races! Running watched my announcement on ESPN, and as I put on my old basketball shorts and laced up my new Nikes, it responded like only running can:
“Go screw yourself. This is hard.”
I got a few minutes up the driveway before I sputtered to a stop. My calves were sore for days. Those dreams were going to need to be on a delayed fuse.
But something started on that run, deep in my physiology. The next one a few days later was a bit easier. It was still impossible and terrible, but at least I could walk the next day. Mile or two by mile or two, I got a bit stronger and a bit faster. In those training books, I had read about weekly miles and workouts and all of these complex training principles that made me miss the forest through the trees.
I didn’t need to have a forest on day 1, or even on day 1000. I just needed saplings. Hundreds of saplings. Thousands of saplings! It’s all about those bomb-ass saplings!
For me, a little over 2000 days later, it led to an overnight success at the 2012 US 10k Championships, where I won and was interviewed by Alex Kurt for Trail Runner Magazine. Those little runs led to adaptations which supported bigger runs, which supported bigger risks, and one of those risks led to a post-race interview with this magazine. A few years later, Alex helped me find a writing opportunity, and that writing opportunity is why you are reading this article today. Give a sapling 15 years, and very cool things can happen.
We see that process over and over in coaching.
An athlete will break out onto the international stage, with an overnight success that was thousands of days in the making. To paraphrase Once A Runner, everyone wants to know The Secret. The unglamorous answer is that there are two ingredients that really matter: consistency and time. Remove the molecules on the bottoms of many pairs of training shoes, one little run at a time.
Those first runs I did were 10 to 20 minutes, and I owe them everything. Even now, I’ll often do very short runs as doubles, or on busy days when nothing else works. Seeing how these short runs can support long-term adaptation, my wife/co-coach Megan and I made a rule for our athletes: “give us 10 minutes” (we talk about it on our podcast here). If there’s a run on the plan, even when life happens, try to do a short jog.
It can be up and down the stairs in your work clothes while preparing for a trial, barefoot around the house on a smoky day with no treadmill available, a lap of the block when anxiety makes it impossible to think about more. Whatever the cause of the compressed run, it’s not a mental trick. We aren’t saying: “Maybe they’ll actually do the full run after they get out there.” We definitely aren’t adding: “Mwhahahahaha!”
For us, it’s all about the physiology of how an athlete can adapt to frequent, consistent running over time. There are four general mechanisms we focus on.
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One: Musculoskeletal adaptations
In the endurance world, running is unique because of impact forces. Each step involves the absorption and transmission of multiple times body weight! Don’t think about that too hard, or you’ll start having erotic dreams about joint pills.
That force causes massive stress on bones, tendons, ligaments, and muscles. With bones, osteoblasts and osteoclasts adapt to each minor stress. But the line between a stress reaction and healthy adaptation is blurry. For example, a 2006 study found that 9 of 21 collegiate runners measured had asymptomatic tibial stress reactions on MRI, with no correlation to subsequent clinical outcomes. In other words, the constant force absorption of running created a background stressor on the bone that likely made it bounce back stronger for those athletes. But it easily could have resulted in full-blown stress fractures too. Consistent, low-level stress helps the body manage these adaptation processes without needing a punch card at the local MRI joint.
Soft tissues work the same way, with each low-level stress spurring strengthening processes. Muscle fiber growth and recruitment is enhanced by consistent stress/recovery cycles, and when the body is transmitting so many tons in such a short time, those stresses don’t need to be long to encourage adaptation. If hypothetical runner A goes out for 1 hour 3 times per week and runner B does 30 minutes 6 times per week, I think runner B not only stays healthier, but goes way faster too, even at longer distances.
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Two: Aerobic and metabolic adaptations
A major friction point for aerobic development is the transportation of oxygen-rich red blood cells to working muscles via capillaries. Running induces angiogenesis, or increased capillarization. Studies on mice involving deep muscle biopsies show that the adaptations can happen with relatively short bouts of exercise on the most adorable mouse treadmills, and the adaptations start to reverse with significant downtime. It works similarly in humans, but there aren’t too many volunteers for the study protocols. While lots of aerobic time is good, any amount can keep those adaptations going. That’s why 10 or 20 minutes can be so much more valuable than taking a zero, especially over longer time horizons.
Simultaneously, after consistent stress, cardiac output increases, with blood volume increasing by up to 20%. Those adaptations don’t take much time investment either, with the bulk of the changes happening relatively early in runs. Running also jump-starts the metabolic system, increasing metabolic rate at rest and reducing it during activity, with improved fat oxidation from repeated endurance stress.
Endurance athletes are sometimes hurt by the attitude that “if some is good, more is better.” That impulse may lead to athletes getting into endurance in the first place, because why else pursue these wild feats of force absorption and aerobic demand? But I think that the statement implies a faulty adaptation relationship. If more is better, then each subsequent mile is more valuable than the one before it, right?
That’s likely untrue. Each subsequent mile is probably slightly less valuable than the one before it from an adaptation perspective, with rapid initial stress causing a boatload of early adaptations. A more accurate physiological description might be: “if some is good, more isn’t quite as good as a per-unit measure, but it will accumulate on top of the good as long as an athlete avoids overstress.” I am not fun at parties.
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Three: Neuromuscular and biomechanical adaptations
The nervous system is wild. Through an immensely complex layering of voluntary and involuntary signals, the brain coordinates running, playing the piano, and masturbation, sometimes in sequence with transition areas if you don’t understand all the rules to triathlon. And it’s not just coordinating movements, but also determining how an athlete perceives effort, responds to stress, and adapts over longer-term cycles. It’s not all in our heads, but a lot of it is, just not in a way we always control.
With consistent training stress, running economy improves dramatically as a given output takes less energy. That’s what happened to me when I first started. I was able to get faster while going longer and using less energy because the nervous system interacted with the musculoskeletal and aerobic systems to make running more efficient. That’s a journey every runner faces at first, and it’s so daunting because the simple act of running is actually very, very complex. Whether it’s running or dancing, repetition is a key element for nervous system changes.
Consistent reinforcement is key, and even short runs do the trick. Add some intensity like hill strides, and running economy can go through the roof relatively quickly.
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Four: Epigenetic and cellular-response adaptations
Genetics is like being dealt a hand of cards. Epigenetics is finding out that it’s you’re working with a special deck, where you can swipe a jack into an ace, or a heart into a spade. Environment and behavior influence the expression of our underlying genetic codes, with extra-long-term changes likely stemming from weakly understood interactions at levels way, way smaller than cells.
How can we determine our genetics? Take a spit test and wait a few decades as the algorithms determine what base pairs are generally associated with athletic performance.
How do we determine our epigenetics? Run consistently for thousands of days and see what happens.
While we are probably not that far from being able to correlate complex individual skills to genetic predispositions, it will be impossible to do with certainty for the foreseeable future because of the murky world of epigenetic interactions. Small, consistent stimuli may help turn some of those epigenetic switches toward endurance. That could explain how athletes can undergo such stunning changes over time (like my own personal change from a bench-pressing football player to a feather-pressing mountain runner).
Throw in other uncertain variables, like endocrine system changes and protein expression shifts. Then mix all of that with the psychology of habit formation, goal-setting, and time management.
Put all of that together, and I am still not sure the exact best way to find your ultimate potential. But I know it involves the consistent accumulation of thousands of running days.
And 10 minutes can get you one day closer.