Recovery Is Not Passive — and the Science Proves It

Hillary Allen is a professional ultra runner and running coach who has competed at the highest level in some of the world's most demanding mountain and sky races. She is no stranger to injury, having faced and documented a serious recovery process publicly, with a candour that has resonated with athletes far beyond the running world.

 Hillary approaches performance and recovery with a scientist's curiosity, regularly diving into the research behind what actually helps the body heal and adapt. She is currently using CurraNZ as part of her injury recovery protocol after picking up an injury that ruled her out of summer racing - and brings that same evidence-led thinking to everything she shares.

What if recovery is also training?

Hillary writes: Injury has a funny way of stripping things down.

The workouts disappear, routines change, and suddenly the thing that once grounded your days feels uncertain. As runners, especially those of us used to chasing goals, fitness, and movement, injury can feel like standing still while the rest of the world keeps moving.

Lately, I’ve been spending more time walking, riding my bike, strength training, and trying to redirect my energy toward things I can control. Some days I feel motivated and hopeful. Other days I miss running so much it physically hurts. Most days, if I’m honest, it’s both at the same time.

But somewhere in the middle of this recovery process, I started thinking about healing differently.

As endurance athletes, we obsess over adaptation. We think constantly about training stress, fueling, sleep, recovery metrics, blood flow, aerobic development, and performance optimization. We understand that the body adapts to stimulus. Yet when injury happens, many of us suddenly become passive participants in our own recovery. We wait. We count weeks. We hope.

The more I thought about it, the more I realized something important: Healing is still physiology.

Recovery is not passive. It’s an incredibly active biological process involving blood flow, immune signaling, inflammation management, tissue remodeling, and cellular repair. Once I started thinking about healing like physiology instead of just “waiting,” my brain immediately went into full endurance-athlete/science-nerd mode:

How do you support blood flow? How do you support recovery without blunting adaptation?

What actually helps tissue repair? Which naturally sent me into a very deep rabbit hole on anthocyanins and blackcurrants. So yes. I have officially become my own recovery experiment.

What initially caught my attention was the research around blood flow and cardiovascular function. One study on trained endurance athletes supplemented with CurraNZ found dose-dependent increases in cardiac output and stroke volume, along with reductions in peripheral resistance during rest. Essentially, circulation efficiency improved, even in highly trained athletes.

The highest dose in the study produced:

·       a 27.5% increase in cardiac output

·       a 17.7% increase in stroke volume

·       a 20.2% reduction in peripheral resistance

Why does that matter during injury recovery?

Because healing tissues need oxygen, nutrients, immune cells, and signaling molecules delivered efficiently. Blood flow is part of the recovery equation.

One of the proposed mechanisms behind these effects involves nitric oxide production. Another paper found that cyanidin-3-glucoside, one of the major anthocyanins found in blackcurrants, increased endothelial nitric oxide synthase (eNOS) expression and significantly increased nitric oxide production in vascular endothelial cells. Nitric oxide helps blood vessels dilate, improving circulation and vascular function.

Tiny berry compounds acting like little traffic controllers for your vascular system? Honestly, kind of incredible.

The more papers I read, the more I realized this wasn’t just a “sports performance” story.

A lot of the mechanisms being studied directly overlap with healing physiology.

One of the most interesting papers examined how blackcurrant extract influenced macrophages, which are immune cells heavily involved in inflammation and tissue repair. Researchers found that blackcurrant extract suppressed pro-inflammatory M1 macrophage activity while shifting signaling toward a more reparative environment.

That distinction matters.

Inflammation itself is not bad. In fact, healing requires inflammation. The problem is excessive or unresolved inflammation that keeps the body stuck in damage mode without effectively transitioning toward repair.

As athletes, I think we sometimes oversimplify recovery into “resting.” But recovery is active work happening beneath the surface. The body is constantly coordinating immune responses, rebuilding tissue, regulating oxidative stress, and adapting to damage.

Another paper looking at blackcurrant anthocyanins and exercise recovery found the extract appeared to support recovery from oxidative stress while maintaining neutrophil function following exercise. Neutrophils are essentially first responders within the immune system and play a major role in coordinating tissue repair and immune defense.

Again, not magic. Not a cure-all. But genuinely fascinating physiology.

So why have I doubled up on a 2 cap daily dose to a 4 cap dose daily of CurraNZ during recovery?

Because right now, recovery is the goal.

Not race prep. Not mileage. Not workouts. Recovery.

I’m trying to support every part of the healing process that I realistically can:

·       sleep

·       fueling

·       circulation

·       mobility

·       mental health

·       inflammation management

·       stress reduction

·       strength work where possible

·       patience (still working on this one)

I don’t think supplements replace consistency, good medical care, or time. But I do think nutrition matters. I think supporting the systems involved in healing matters. And I think athletes often put tremendous effort into training hard while underestimating how intentional recovery can be.

My “training” right now looks different than I expected it would this season. There’s more biking, more walking, more gym sessions, more reflection, and probably too many late-night science paper deep dives. But I’m starting to realize that maybe this phase is still building something important, even if it doesn’t look like traditional fitness.

Maybe recovery still builds resilience.
Maybe it builds perspective.
Maybe it builds patience.
Maybe it builds trust in the process.

And maybe healing deserves the same level of attention and commitment that we normally reserve for training.

So if you’re injured right now, here’s the question I’ll leave you with:

Are you simply waiting to heal, or are you actively supporting healing?

Because those are two very different mindsets.

And maybe recovery still counts as training after all.