Why Downtime May Lead To Breakthroughs

Breaks make breakthroughs.

You know that statement is true because you could imagine it on a motivational poster of a puppy in a paw cast. To double-check the puppy-poster proof, I went through a list of the athletes that I coach. Every single one had some sort of layoff preceding their biggest accomplishments.

Injuries? This is running, so … yeah, it can seem like a cereal commercial with the number of snaps and crackles and pops. Some athletes had to stop running for months or years. Some were told they might never run again, only to come back and exceed anything they achieved before.

Here’s an objective, scientific fact: downtime is not a failure. It’s about more than that, though. The theory of this article is that if you play your cards right, breaks can lead to exponential growth processes that reset what you could have ever thought possible before the layoff. 

Mental-health breaks? This is sentience, so … yeah, there were plenty of those too. Breaks come in many forms, good and bad, planned and unplanned, pregnancies and pandemics. Whatever caused the breaks, the act of taking downtime was often hard on those athletes. We all have those questions sometimes.

Champions don’t take downtime, right?

Maybe I’m not cut out for this?

Am I losing everything?

Here’s an objective, scientific fact: downtime is not a failure. It’s about more than that, though. The theory of this article is that if you play your cards right, breaks can lead to exponential growth processes that reset what you could have ever thought possible before the layoff. 

 

Let’s start with the principles of fitness maintenance.

We’ll start here as an excuse to discuss how it’s easy to have misconceptions about how fitness changes and grows over time. A 2021 article in the Journal of Strength and Conditioning Research found that endurance performance can be maintained for 15 weeks on as little as two sessions per week, or when volume is reduced by up to 66% (as short as 13 to 26 minutes per session). The review article findings were based on a few studies that had untrained individuals do 10 weeks of six times weekly training sessions, followed by a detraining period of 15 weeks where participants were randomly assigned to reduced frequency, reduced intensity, and mixed groups. As long as there was some maintenance of intensity, participants did not significantly detrain.

Similar findings applied to strength training, with as little as one session a week being effective for maintenance in younger populations, and two sessions for older populations. The general conclusion of the review is that both frequency and volume can be reduced while maintaining fitness, with volume in particular being acceptable to drop by substantial margins over 50%. 

The general conclusion of the review is that both frequency and volume can be reduced while maintaining fitness, with volume in particular being acceptable to drop by substantial margins over 50%. 

I could walk 500 miles, and I could walk 500 more while reciting disclaimers. The studies apply in a narrow context for the general population, not for runners trying to optimize performance. And over longer time horizons, it’s likely that maintenance becomes short-term fitness loss as past adaptations start to fade. But the general principles overlap with the experiences of coaches and athletes about why it’s OK to take downtime. 

All tie back to a general principle: once training levels reach a certain point, there might be variance around that point based on training status, but it’s always relatively quick to get back to those levels. Even if you feel out of shape, the past work you have completed is right there at the surface, ready to shine after a quick polish. That’s due to how the body retains training adaptations with time. 

 

Decreases in VO2 max take time and levels rebound quickly.

A 1989 article in Sports Medicine found that VO2 max decreases start to begin after two to four weeks fully off, tied to reduction in cardiac output and blood volume. Follow-up studies generally find around a 5% reduction after two weeks, and up to 20% at eight to 10 weeks. 

While VO2 max may drop with time off, it doesn’t take much to maintain it. For example, a 1985 study in the Journal Of Applied Physiology had athletes reduce training from six to 10 hours per week to one 35-minute session, and those athletes had no reduction in VO2 max (but their performance decreased, likely due to changes in muscular output and efficiency). And even after total detraining, VO2 max bounces back with some focused intensity. 

However, that initial VO2 max reduction may make running feel hard at first, especially when trying to go harder. After a few weeks off, even slight hills make my breathing sound like a broken harmonica. Don’t worry, you’ll be ready to rock within a few weeks. 

However, that initial VO2 max reduction may make running feel hard at first, especially when trying to go harder. After a few weeks off, even slight hills make my breathing sound like a broken harmonica. Don’t worry, you’ll be ready to rock within a few weeks. 

 

Blood volume changes happen fast in both directions.

Similarly, blood volume and cardiac output are highly sensitive to both time off and reintroduction of training. Another 1985 study in the Journal of Applied Physiology found a 9% reduction in blood volume and a 12% reduction in stroke volume after two to four weeks of inactivity in trained men. On the flip side, a 1991 review in the Medicine and Science in Sports and Exercise journal found that blood volume increases quickly as training is reintroduced. And a 2015 study in the European Journal of Applied Physiology found a 17.8% increase in plasma volume in highly trained cyclists after just four exposures to post-exercise sauna.

Blood volume and stroke volume feed back into VO2 max, so the initial feeling of being underwater and gasping for air upon returning to exercise is likely going to be short-lived. Plus, as demonstrated by the 2021 study on detraining, it takes very little relative training to maintain baseline levels.

 

Detraining is gradual for the metabolic and aerobic systems.

A 2000 review in Sports Medicine found that after around a week, the body may start to rely more on carbohydrate metabolism, with reduced capillary density too. Those adaptations make the body work harder to get energy to working muscles and limit endurance—part of the reason why you might struggle immensely on runs over 60 to 90 minutes after a longer break. Again, the changes are reversed relatively quickly with reintroduction of training, and can be maintained at lower training levels.

 

Neuromuscular and biomechanical lag.

Running economy decreases short-term as the nervous and biomechanical systems get slightly less efficient. That could explain why those first few runs after a layoff feel so foreign, even if you have been cross training. In coaching, I often see athletes start to feel less awkward after a week, and downright natural after intensity is reintroduced (usually via hill strides to start). And muscles may lose some strength, particularly after very long breaks (like severe injuries). But as reviewed in 2019 in Frontiers of Physiology, nuclei may not be lost from muscles during that process, possibly contributing to quick bounce-back cycles.

So studies and training theory are generally in agreement: detraining starts after a week or two, progresses for a month or two, and begins to level off, with some ongoing muscular changes. It can feel like you’re so far away from where you were! 

But here’s why I’m never worried about that downtime, whether it includes maintenance or not. Athletes usually have a rapid return to previous fitness levels with a small dose of consistency, with it being much easier to achieve again than it was the first time. Restarting training is awakening a sleeping giant. 

But here’s why I’m never worried about that downtime, whether it includes maintenance or not. Athletes usually have a rapid return to previous fitness levels with a small dose of consistency, with it being much easier to achieve again than it was the first time. Restarting training is awakening a sleeping giant. 

It’s not just that, though. The sleeping giant may wake up with superpowers. 

While the science is unsettled, there are so many stories of massive breakthroughs coming off downtime ranging from a few weeks to a few years that there must be physiological resets that raise the ceiling on long-term potential for some athletes. Let’s look at a few possible explanations. 

 

Long-term recovery.

Every training session introduces some acute stress—muscular fatigue/damage, increased cortisol, hormonal disturbance. That acute stress is the whole point of training, allowing an athlete to build back stronger after adaptation. But some of those acute stresses have long tails. Take muscle damage as an example. If we did a blood test after a hard training session, there might be elevated creatine kinase, indicating some muscle breakdown. An athlete may report some subjective fatigue mirroring those results, subsiding in a day or two. Then they’ll do another workout. Heck, yes, adaptation!

Downtime can wipe the stress slate clean. Sometimes, athletes find that they were carrying a chronic stress weight vest around without realizing it.

But wait. While subjective fatigue may be approaching baseline, if we did a follow-up blood test, there would be a good chance that the athlete wasn’t fully at baseline, especially in heavy training. That’s how acute stresses can add up to become chronic stress—the long tails get stacked up over time. While chronic stress can be optimized with plenty of recovery and fuel, it’s always a risk of hard training.

Downtime can wipe the stress slate clean. Sometimes, athletes find that they were carrying a chronic stress weight vest around without realizing it.

 

Nervous/endocrine system hypotheses. 

The interplay of the brain and hormones in long-term growth is weakly understood due to how hard the neuromuscular and endocrine systems are to measure and isolate. For the nervous system, overtraining syndrome is a prime example. A 2020 study reviewed what we know about OTS—a series of dysfunctional adaptations to excessive training and inadequate fueling, with major nervous system impacts.

While approaches vary, the general rule is that a full shut-down of training is needed in severe OTS cases. Athletes often can’t jog their way through OTS, they need to eat and sleep and chill their way through it. Even if downtime is not in response to overtraining specifically, the same rules may be relevant: the nervous system works on longer time scales when responding to chronic stress.

For the endocrine system, sex hormones estrogen and testosterone can be reduced in hard training for endurance athletes, with evidence that the hormones may increase during downtime. As with the nervous system, there may be longer-term endocrine system processes at play when it comes to how hormonal changes affect health. 

 

Gene expression and epigenetics.

Our genetics are not just a set of instructions that we can’t influence. External stimuli change how our genetic code expresses itself via epigenetics, and there is even some evidence that epigenetic changes can be heritable. With endurance sports, relatively small stimuli may start turning some of those epigenetic switches toward endurance. While it’s debated, that could be one explanation for how bodies can undergo such fundamental and positive changes over time even if exercise routines are a few minutes a day.

If I had to venture a guess about why breaks precede breakthroughs, it would be that major reductions in training may have a priming effect on adaptations to future stimuli.

So what happens with downtime? We’re not sure. But if I had to venture a guess about why breaks precede breakthroughs, it would be that major reductions in training may have a priming effect on adaptations to future stimuli. That could involve some mix of all of these physiological processes, plus other cellular-level processes like protein expression or mitochondria changes. Or maybe it has to do with the brain and neuromuscular system. 

Whatever the exact cause, breaks are not something to fear and certainly not a reason to beat yourself up. Call it the Dell PC Theorem—sometimes turning it off and turning it back on can solve problems that slow everything down.

 

What does it all mean in practice?

I don’t know. I don’t think anyone knows. And that concludes my TED Talk.

Wait, not quite done. Here’s what I do know: the “breaks make breakthroughs” principle is seen over and over again, in every sport. It might just be availability bias, but I don’t think so. What I think is happening is that the principles of maintenance of training interact with detraining and longer-term recovery in a way that compounds interest on underlying athletic potential.

When an athlete first starts training, the body takes some time to build up. You know the feeling—immediate gains followed by slow progress. From that new normal, our bodies can detrain and rebuild relatively rapidly, getting back on the slow progress trend.

But maybe every athlete isn’t designed for slow progress indefinitely. Maybe they even face stagnation or regression no matter how hard they work. Whether it’s due to chronic stress or just our baseline genetics interacting with training over many years, some athletes may find themselves on a trajectory that undersells their ultimate potential.

Break. Injury. Burn-out. Pandemic.

What builds back from that break? There’s no certain answer, but I have my theories. And if you have had to take downtime, just know that all of those theories point to four words when it comes to your future. 

DREAM REALLY, REALLY BIG. 

 

David Roche partners with runners of all abilities through his coaching service, Some Work, All Play. With Megan Roche, M.D., he hosts the Some Work, All Play podcast on running (and other things), and they wrote a book called The Happy Runner.

 




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