Zone 2 vs. HIIT: Which One Should You Really Be Doing?
Which One is Better?
“Zone 2 is better than HIIT.”
“HIIT is better than Zone 2.”
“You’re doing it wrong if you’re doing X.”
My neck hurts trying to follow all the back-and-forth.
So… is any of it true?
Naturally, I had to see what my Instagram followers thought too, so I took it to the polls.
Now let’s break down the claim, the nuance, and the science behind it.
“Better” is a Subjective Term
Whenever someone says something is better, the next question should always be: better for what? better for whom?
Better for longevity?
For fat loss?
For cardiovascular health?
For your schedule or energy levels?
These are the questions that tend to get lost in the social media debate, but they matter a lot when deciding what’s “better” for you.
What is Zone 2 Cardio?
There’s no single, universally accepted definition of Zone 2.
Generally, Zone 2 refers to low-to-moderate intensity cardio.
The effort level where you can still hold a conversation with a friend.
It’s often around 60–70% of your max heart rate, but individual differences (and how you measure it) can make that fuzzy. So take that range with a grain of salt.
Zone 2 training is the bread and butter of endurance athletes.
It builds your aerobic base, you can do a lot of it and recover well, and it’s the foundation for everything else.
The bottom line: Zone 2 is sustainable, easy to recover from, and sets the stage for harder training down the road.
What is HIIT?
If Zone 2 is the long, steady burn, HIIT is the firecracker.
High-Intensity Interval Training (HIIT) involves short bursts of near-max effort (usually ≥90% of your max heart rate), followed by rest or active recovery.
Think: all-out for 30 seconds, rest for 60, repeat.
Most people love HIIT because it’s time-efficient.
The biggest reason people skip exercise is lack of time, and HIIT directly solves that.
In fact, brand new 2025 study shows that every 1 minute of high-intensity exercise can be equivalent to:
4–9 minutes of moderate-intensity
53–156 minutes of low-intensity cardio
That’s really time efficient!
And it’s not just for athletes.
HIIT has benefits for clinical populations too, from cardiovascular disease to metabolic syndrome.
That said, HIIT requires high effort and more recovery.
Too much of it, too soon, or done without proper conditioning can backfire.
Beginners may want to start training HIIT using a stationary bike or airbike, since these machines let you reach peak intensity without the technical skills required for sprinting, rowing, or jump roping at high intensity.
If you’re proficient in running, rowing, jump rope, etc., and have been training at lower intensities, then you could incorporate them into your HIIT sessions.
What Zone 2 and HIIT Can Do for You
Before we start pitting them against each other, it’s worth pointing out that both Zone 2 and HIIT have a lot in common when it comes to what they actually do for your body.
You might be surprised at just how much overlap there really is.
Here’s what they can actually do for you:
Build endurance. Being able to go longer without completely gassing out, whether that’s during a workout, a run, or chasing your kids up the stairs.
Improve mitochondrial efficiency. Your cells get better at using oxygen to create energy, so workouts feel smoother and recovery gets easier.
Enhance fat oxidation. You become better at using fat as a fuel source (not exactly the same as “fat loss,” but a big win for metabolic health).
Increase metabolic flexibility. Your body gets better at switching between fat and carbs for energy, so you can perform well across different workouts and recover faster.
Boost VO₂ max (aerobic power). Your body’s ability to take in and use oxygen, a strong indicator of cardiovascular fitness and longevity.
Improve insulin sensitivity and metabolic health. Your body handles carbs more efficiently and maintains steadier energy levels throughout the day.
Support body composition goals. Paired with resistance training, both HIIT and Zone 2 can help improve muscle-to-fat ratio and overall leanness.
Sharpen cognitive function. Better blood flow and oxygen delivery to the brain means clearer thinking, improved mood, and reduced stress.
So yeah, both Zone 2 and HIIT are doing a lot of good under the hood.
The real question isn’t whether one works better, it’s how, when, and how much of each makes sense for you.
That’s where the nuance comes in (and where most social media misses the mark).
The Nuance
If you’re short on time and want maximum return on investment, HIIT might be the better fit.
If you’re training for an endurance event, or just want a solid aerobic foundation, Zone 2 should probably take up the bulk of your cardio, with HIIT sprinkled in 1–2 times per week.
You also need the capacity to do HIIT safely.
If you haven’t run sprints since middle school gym class, maybe start with a stationary bike or rower.
For most people, the best approach isn’t HIIT OR Zone 2.
It’s HIIT AND Zone 2, combined in a way that fits your fitness level, recovery, and goals.
Because when it comes to cardio, the real answer to “which one is better?” is:
The one you can actually do consistently without burning out.
How to Use Both (Without Losing Your Mind or Your Recovery)
Here’s the good news: you don’t have to pick a side. HIIT and Zone 2 can, and should, coexist in most training programs.
The key is knowing how much of each to do, and when.
If you’re short on time
HIIT is your friend.
Two to three short sessions a week (15–25 minutes, including warm-up) can deliver big returns for cardiovascular fitness and metabolic health.
Just make sure you’re actually hitting intensity during the work intervals.
If you can talk, it’s probably not HIIT.
If you’re building your base
Zone 2 should be your foundation.
It builds the aerobic “engine” that allows you to handle more volume and recover faster between higher-intensity sessions.
If you have the time, you can do a lot of it, spread however you like: brisk walks, runs, bikes, hikes, whatever you’ll actually do.
If you’ve ever wondered why your hard workouts feel harder than they should… odds are your aerobic base could use more love.
If you like variety
Mix and match. A balanced week might look like:
2–3 Zone 2 sessions (easy-to-moderate effort for 30–60 minutes)
1–2 HIIT sessions (short, all-out intervals)
Minimum 2 strength sessions (because cardio and strength are better together)
This combo hits every energy system, supports muscle and metabolism, and keeps training interesting.
If you’re feeling rundown
Pull back the intensity.
HIIT adds stress.
Great stress when managed well, but still stress.
If you’re not sleeping well, feeling moody, or dragging through workouts, HIIT should be limited.
Zone 2, on the other hand, can actually help recovery by improving circulation and supporting your nervous system.
Finding the Right Balance
This is exactly what I help my clients do.
Find the balance between doing enough intensity to make progress, but not so much that it tanks recovery, energy, or hormones.
Most people don’t need to overhaul their training.
They just need to understand what kind of cardio (and how much of it) actually supports their goals.
Whether that’s building strength, improving endurance, or just feeling like themselves again in their workouts.
At the end of the day, fitness doesn’t have to be all-or-nothing.
You can have days where you go hard, and days where you cruise.
You can train smart, make progress, and still feel good doing it.
That’s the balance.
And when you find it, that’s when everything starts to click.
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