Is Zone 2 Training Overhyped? An Honest Take for Adults Over 40
Zone 2 got a huge wave of hype, then a backlash calling it overrated. Neither take is right. Here's the honest version.
Peter Attia said Zone 2 might be the single most important thing you can do for long-term health. Then, predictably, the backlash arrived: it's overhyped, it's boring, it's just "easy cardio" repackaged with a cooler name so podcasters have something to talk about. Both takes are wrong, and the reason they're both wrong is the same reason: neither one is actually about the physiology.
Here's my honest take, after running this myself and writing about the mechanics of it in the Zone 2 how-to guide: Zone 2 isn't overhyped. It's under-done. Almost nobody actually does enough of it, and the hype cycle is a distraction from that much more boring, much more true fact.
The hype was never really about Zone 2
Go read the actual case for Zone 2 and it's not exciting: mitochondrial density, capillary growth, stroke volume. None of that is a headline. What became a headline was the framing — "the zone Olympic athletes train in 80% of the time," "what longevity doctors actually do." That framing is true, but it's marketing dressed as physiology, and it invited an equally marketing-driven backlash: "actually it's overrated, here's why HIIT is better."
Neither the hype nor the backlash is arguing with the data. They're arguing with each other's tone.
Where the backlash gets it right
The backlash is correct about one real thing: Zone 2 alone, with no strength training and no hard effort ever, isn't a complete program. If you're using "I do Zone 2" as your entire fitness identity, you're missing muscle mass, you're missing the VO2 max ceiling that only near-maximal effort raises — I've laid out that split in detail here — and you're probably underestimating how much of the benefit came from just moving consistently, at any intensity, rather than from the specific zone you picked.
That's a fair critique of Zone 2 maximalism. It's not a critique of Zone 2 itself.
Where the hype gets it right
The actual adaptations are real and they're not marketing. Denser mitochondria mean your cells produce aerobic energy more efficiently — better fat utilization, more sustained energy, real metabolic resilience. Stroke volume — how much blood your heart moves per beat — improves with sustained aerobic work and shows up as a lower resting heart rate over months. These aren't trendy claims. They're some of the more replicated findings in exercise physiology, dating back long before anyone called it "Zone 2."
What's actually new isn't the physiology. It's that someone finally gave a name to "sustained moderate aerobic work" catchy enough to make people ask about it. The backlash mistakes the marketing surge for a claim about the training itself.
The part that actually matters for you
Neither side of this argument is really talking to you — a 35–55-year-old managing a job, a family, and a recovery budget that isn't what it was at 25. For you, the relevant question isn't "is Zone 2 hyped." It's: what's the training input that produces real adaptation, costs almost nothing in recovery, and fits into a schedule that's already full?
That's not a hype question. That's a cost-benefit question, and Zone 2 wins it clearly — not because it's trendy, but because the alternative to "boring cardio you can sustain" is usually "no cardio at all," which is what actually happens to most people who wait for a more exciting option.
If you lift and think that covers it, it doesn't — not for the aerobic base specifically. If you've been avoiding Zone 2 because the discourse made it sound either magical or overrated, ignore the discourse. Here's how to actually do it, without a Garmin, without an 18-week triathlon plan, in whatever time you already have.
Fortiv treats Zone 2 as one of three core training inputs — not the whole program, not a fad. Join the waitlist to be first when we launch on iOS.