Monthly Mythbust: What the influencers are missing about Zone 2 training
The human body isn't a checklist and Zone 2 isn't a biohack.
Most longevity influencers have no idea how to actually train
Recently, three (yes, three) incredibly smart, athletic, data-driven people reached out to me about Zone 2 training. They were confused by conflicting advice they’d heard from longevity influencers on podcasts. One of them was especially annoyed because they were “dinged” on their wearable for not getting enough Zone 2. One could not figure out why her zones didn’t match her perceived intensity (turns out it was based on a formula, not her actual data). One had a wearable that indicated a “Zone 0,” which does not exist in any of the training models I’ve ever worked within.
The misguided obsession with Zone 2.
As a nutrition and exercise scientist (as well as a coach and physiology professor for more than two decades), this podcaster obsession around Zone 2 training is getting absurd, and honestly, is really kind of dumb.
Most of the current longevity conversation around heart rate zone training has drifted into this strange checklist culture and completely misses the point of why we use zone training in the first place.
People talk about Zone 2 as if it is a prescription to fill, mitochondria as if they are widgets to be built and scaled, and metabolism as if it is a software upgrade. The narrative treats the body like a collection of independent metrics to be quantified rather than a system meant to adapt through progressive training and recovery.
It all sounds very scientific when delivered by a confident fast talker with a microphone, but it gives away something pretty obvious …
Most of the influencers leading discussions about zone training have clearly never actually coached anyone.
If you’ve coached, you see zones as training targets. Zones are not hacks. They are a shared language that helps the coach and athlete build a longitudinal training plan. They exist to improve outcomes overtime and set a tone so both coach and athlete know why they are doing the work and how it fits into a broader goal.
A recent review, “Much Ado About Zone 2,” written by exercise physiologists and coaches, is a great read on how zone training is actually used in practice.
Overall, zone training looks something like this:
Rates of Perceived Exertion & Training Zones
When a coach prescribes Zone 2, it is not because the athlete needs “mitochondrial biogenesis.” It’s because the athlete needs to build the aerobic and skills base that supports everything else.
A coach might send an athlete out for an easy 90 minutes, not to chase a marker of mitochondrial efficiency, but to strengthen the body to allow tougher sessions in the future without breaking. The athlete practices the rhythmic breathing, the correct placement of the foot, stride, or pedal stroke and the confidence that comes from really getting to know their sport.
The same perspective applies to Zones 3, 4, and 5. Longevity culture often describes them as if they exist only to stimulate specific cellular pathways. But coaches and athletes use them to refine skills at pace.
Zone 3 (i.e. tempo training) teaches pacing and focus. It helps the athlete sit in mildly uncomfortable territory without drifting into form breakdown that results from fatigue. And, it will also be the indicator that the other training is working. It is the canary in the coal mine. If zone three get easier (i.e. same pace, lower heart rate), your training plan is on point. If zone three is hard to hit, you’re overreaching or overtraining.
Zone 4 builds the ability to push a “just out of reach” pace for stretches at race distance or shorter. This is the pace that is designed for performance. I think of it like bubbles in a cup of fountain soda (or beer!). You fill, let the bubbles recede, and then put a little more in. Eventually, you top off the cup.
Zone 5 is the other perfect example of misunderstanding training. The longevity crowd often describes VO2 max intervals as if you can simply accumulate the required minutes per week and call yourself optimized. But Zone 5 intervals are short, sharp, and push the athlete to the edge of their capacity, forcing physiologic improvements while maintaining form. The athlete learns how to recover between reps, which in the future become shifts, heats, and finals. They learn what it feels like to stay mentally present when their lungs are screaming and legs are burning. And, for an athlete, those adaptations are as important as any physiological gains. They build resilience and confidence, which in turn make the next cycle of training even more effective.
Longevity culture’s oversimplification of zone training.
Longevity culture tends to completely ignore these critical complexities of zone training. Influencers give the impression that if you simply hit the right minutes in each zone, you will become an “optimized” being. (Anyone else getting really sick of this word?) They ignore the human experience of training and the iterative relationship between coach, athlete, and training plan.
Mistakenly, the longevity set often attributes Zone 2 (i.e. longer, easier minutes) to improving VO2 max. This is absolutely incorrect. In order to improve VO2 max, you have train there. This means strategically using Zones 3,4, and 5 to push boundaries, while also improving skill and allowing for recovery in Zones 1 and 2.
And there is a deep irony here: If you train like an athlete, with purpose and progression, you end up achieving far better longevity outcomes than if you chase longevity.
Athletes build aerobic bases, which support mitochondrial health. They cycle in tempo work, which improves lactate utilization. They perform VO2 max intervals, which strengthen the heart and increase peak oxygen uptake. They practice Zone 2 recovery sessions, which restore overreaching systems. They strategically train across zones because this smart variation is what makes the body perform well. And a high performing body is, almost by definition, a body that ages well.
This is the part the optimization world often misses.
Coaching, and smart programming, builds from the outside in.
You start with the question of what the athlete wants to do and who they want to become. The training plan and physiology follows.
Longevity culture tries to build from the inside out.
It starts with the cellular mechanism and hopes the lived experience will assemble itself around the theory. This is absolutely backwards.
Zones are useful only when grounded in training goals.
If the goal is a life filled with energy, strength, ease of movement and the confidence that comes from knowing your body can meet the demands of real life, then zone training must be tied to something deeper than a checklist.
Longevity is the natural byproduct of living in a body that is trained with purpose.
The goal is not to be optimized according to your recovery score. Coaches understand this because they live inside the process with their athletes, striving toward a goal together. It is not a performance hack. It is a longitudinal goal that requires progressive and adaptive training, not simply checklists of minutes. And this is why my friends are confused — because the numbers have become completely disconnected from the goals.
Maybe longevity culture will eventually catch up, although I’m not hopeful. In the meantime, if you’re taking advice from optimizers on podcasts, stop and find yourself a seasoned coach instead.