ZONE 2: SMART TRAINING, OR BUZZWORD?

What is 'zone 2' and Is it a sacred ritual that we need to obsess over?

Zone 2 (or low-intensity aerobic work as we enjoyed calling it for half a century) has re-invented itself recently. What is effectively the most boring of training modalities has now become a hot-ticket term that makes people feel like they’re doing science. It's as though adding a Z-word in front of it has made it the sword wielding Spanish heart-throb of fitness methodologies.

Mocking aside, there is real physiology behind zone 2.

However, somewhere along the way, it’s been turned into a kind of sacred fitness ritual — as if everyone needs to obsess over heart rate zones, nasal breathing, and whether their watch says they’re sitting at exactly the right number of beats per minute.

So let’s simplify it.

“Do I need more low-intensity aerobic work in my week?”

The answer is:

Sometimes yes. Sometimes no. It depends entirely on the rest of your training.

First: what actually is Zone 2?

Broadly speaking, Zone 2 refers to low-intensity aerobic training, work that sits below your first major threshold, where you can still hold a conversation and you’re not accumulating much fatigue.

It’s often associated with easy running, cycling, incline walking, rowing, longer aerobic sessions, generally the kind of cardio you can recover from relatively well.

At a physiological level, this type of training is associated with improved aerobic capacity, increased mitochondrial density, better capillary development, improved fat oxidation and a greater ability to tolerate training volume over time

So yes, it has real value.

But here’s the important bit:

Zone 2 is useful because of what it supports, not because it’s magic in isolation.

That distinction matters.

Zone 2 is not magical. It’s contextual.

A lot of the internet talks about Zone 2 as if it’s some newly discovered performance secret.

It isn’t.

People have been doing low-intensity aerobic work for decades. What’s changed is mostly the branding.

A lot of what is now called “Zone 2” is, in practice, just easy cardio with a purpose and that purpose is usually one of two things:

1. To build aerobic volume, or

2. To balance out harder training.

That second one is where the conversation gets more useful.

Because the real value of Zone 2 often isn’t that it’s “special”.

It’s that it gives you a way to keep moving, support recovery, build your aerobic base and add training without constantly smashing yourself.

That’s helpful if you’re already doing enough demanding work to create meaningful fatigue.

But if you’re not?

Then the question changes.

This is where people get confused. A lot of people hear that elite endurance athletes do loads of Zone 2 and assume that means they should too.

But that logic falls apart pretty quickly.

Elite and high-volume athletes often need a lot of low-intensity work because they’re also doing a lot of volume, a lot of fatigue and enough hard training to require strategic balancing

That’s very different from someone doing 2–4 sessions a week, moderate total training load

and no huge fatigue to manage.

Recovery work only really matters if there’s something substantial to recover from.

That’s the bit people don’t always want to hear. Because Zone 2 sounds smart, disciplined, and productive.

But in a lot of cases, it’s being used as a kind of default “good behaviour” — not because it’s the best tool, but because it feels safe.

And sometimes, safe is exactly what’s holding progress back.

The better question is not “Should I do Zone 2?”

It’s this:

What is this session actually doing for me? What adaptation am I trying to drive here?

Because if your week already includes hard intervals tempo work, sprinting, heavy strength training or high overall training load…Then yes, low-intensity aerobic work can be very useful. It gives your body a chance to circulate blood, maintain movement, build volume and recover without adding too much stress.

That’s a smart use of Zone 2.

But if your training week is already fairly light?

Then it becomes fair to ask whether that “Zone 2 session” is actually earning its place.

This is especially relevant for runners. This is where runners in particular can get a bit confused because a lot of runners are told that the answer to almost everything is:

More easy mileage.

And sometimes that’s true. But sometimes not. If you’re only running a few times per week and your biggest limitations are speed, power, mechanics, strength or quality…then another low-intensity aerobic session IS NOT be the best return on time.

That’s especially true if you’re constantly replacing sprint work, strength sessions, threshold work, or quality running with more easy running because it feels “smart” and “sustainable”.

That’s not smart. it’s just comfortable.

A lot of people don’t need more recovery work, they need more work worth recovering from.

That’s the distinction.

Because if your week doesn’t contain enough meaningful stimulus to justify all this caution, then your problem may not be that you need more Zone 2. Your problem may be that your training simply isn’t demanding enough in the right areas.

Zone 2 can also become a place to hide.

This is where the article gets a bit uncomfortable.

Because for some people, Zone 2 becomes a very respectable way of avoiding harder training. It might feel healthy or productive or “optimised” but your progress will quietly stall.

So… do you need Zone 2 training?

Here’s the honest answer:

Yes - if your overall training load is high enough that low-intensity aerobic work helps you absorb harder sessions and recover well.

But absolutely not if your weekly training load is modest and your time would be better spent on more meaningful work. Easy work only makes sense in proportion to the amount of hard work surrounding it.

That’s the bit the internet often skips.

So Zone 2 is not nonsense, but it’s also not a personality. It’s just low-intensity aerobic training. Whether you need more of it depends less on what your watch says and more on a much simpler question:

What is your current training actually asking your body to recover from?

If the answer is “not much”, then your training might need more challenge, not more caution.

And for most of you reading this, that’s a far more useful place to start.

-Craig.