If your social media feed looks anything like ours, you've probably seen Zone 2 cardio everywhere. Influencers swear by it. Longevity experts preach it. Your mate who just bought a rowing machine won't shut up about it.
But here's the thing. In 2025, new research published in Sports Medicine just threw a massive spanner in the works. Turns out, a lot of what you've been hearing about Zone 2 might be wrong.
Let's cut through the noise and figure out what Zone 2 actually is, who it's really for, and whether you should care about it at all.
What is Zone 2 cardio, actually.
Zone 2 is cardio training at 60-70% of your maximum heart rate. That's the simple version.
It's the intensity where you're working hard enough to feel it, but not so hard that you're gasping for air. You should be able to hold a conversation, but you'd sound slightly breathy to someone on the other end of a phone call.
Think of it as the sweet spot between a casual stroll and actually pushing yourself. You're sweating, your heart rate is elevated, but you could theoretically keep this pace for 30-60 minutes without collapsing.
Exercise physiologists call this "steady-state aerobic exercise." Normal people call it "not trying to die."
The big controversy everyone's talking about.
Here's where things get interesting. For the past few years, Zone 2 has been marketed as the optimal intensity for mitochondrial health, fat burning, and basically every good thing your body can do.
Then in 2025, Canadian researchers published a narrative review that basically said: not so fast.
Their findings were blunt. Current evidence doesn't support Zone 2 as optimal for improving mitochondrial capacity or fat oxidation for most people. In fact, higher intensity training appears more effective for these adaptations, especially when you've got limited training time.
The researchers pointed out something crucial. Most Zone 2 recommendations stem from observing elite endurance athletes who spend massive volumes training at low intensity. But these athletes also do high-intensity work, have years of training adaptation, and exercise 15-20+ hours per week.
You, scrolling through Instagram while sitting on your couch, are not that athlete.
So who is Zone 2 actually for.
Based on the current evidence, Zone 2 training makes the most sense for:
Elite endurance athletes. If you're training for marathons, ultra races, or multi-hour cycling events, Zone 2 builds the aerobic base that lets you sustain long efforts. It's part of a polarised training approach where most work is easy, with strategic high-intensity sessions.
Recovery and active rest. Zone 2 is brilliant for low-stress movement that promotes blood flow and recovery without taxing your system. It's cardio that doesn't interfere with your strength training.
People who hate HIIT. If high-intensity training makes you miserable and you won't stick with it, Zone 2 is infinitely better than doing nothing. The best exercise is the one you'll actually do.
Building an aerobic base. If you're new to cardio or coming back from injury, Zone 2 helps you build capacity without overdoing it.
But if you're a regular person with limited training time who wants maximum health benefits, the research suggests you're better off including higher-intensity work in your routine.
How to actually calculate your Zone 2 heart rate.
There are three common methods, ranging from dead simple to surprisingly precise.
The age formula (least accurate but easiest).
220 minus your age equals your estimated max heart rate. Then multiply by 0.6 and 0.7 to get your Zone 2 range.
Example: If you're 35 years old:
● Max heart rate: 220 - 35 = 185 bpm
● Zone 2 lower limit: 185 x 0.6 = 111 bpm
● Zone 2 upper limit: 185 x 0.7 = 130 bpm
● Your Zone 2 range: 111-130 bpm
This formula is rubbish for serious athletes but fine for getting started.
The talk test (surprisingly accurate).
Research from the American College of Sports Medicine validates this beautifully simple method.
If you can speak in full sentences without gasping, you're in Zone 2. If you have to pause mid-sentence to catch your breath, you're creeping into Zone 3. If you can sing, you're too low.
Try reciting a few lines of a song, counting to 20 out loud, or answering a question. If your breathing makes this uncomfortable but not impossible, you're right in the zone.
VO2 max or lactate threshold testing (most accurate).
This requires lab testing where you'll wear a mask while running or cycling at increasing intensities. Expensive and unnecessary for most people, but if you're serious about training, it gives you precise, personalised zones.
What actually counts as Zone 2 cardio.
Any rhythmic, sustained activity works. The key is maintaining that steady heart rate for an extended period.
Popular Zone 2 options include:
● Brisk walking or hiking
● Light jogging
● Cycling at a moderate pace (perfect on a VERVE bike or rower)
● Rowing with controlled, steady strokes
● Swimming
● Elliptical or cross-trainer work
The activity doesn't matter. What matters is that your heart rate sits in that 60-70% range and you can sustain the effort.
Zone 2 vs high-intensity training: what the research actually shows.
The 2025 review made it clear. When training time is limited (which it is for most people), higher-intensity intervals produce superior improvements in:
● VO2 max (cardiorespiratory fitness)
● Mitochondrial signalling and adaptations
● Cardiometabolic health markers
● Time efficiency
That doesn't mean Zone 2 is useless. It means if you've only got 3-4 hours a week to train, spending all of it at low intensity probably isn't optimal.
The better approach? A polarised model. Most endurance athletes do roughly 80% of training at easy intensities (Zone 1-2) and 20% at hard intensities (Zone 4-5). Very little time is spent in the murky Zone 3 middle ground.
For regular people, this might look like:
● 2-3 weekly sessions of higher-intensity cardio (12-30 minutes of intervals or steady hard effort)
● 1-2 weekly sessions of Zone 2 work (30-60 minutes)
●Walking and daily movement that doesn't count as structured training
How to use Zone 2 without wasting your time.
If you're going to include Zone 2 training, here's how to do it properly:
Duration matters. Zone 2 sessions should be at least 30 minutes, ideally 45-60 minutes. Shorter efforts don't provide enough stimulus to drive adaptation.
Frequency depends on your goals. Endurance athletes might do 3-5 Zone 2 sessions weekly. Regular lifters adding cardio might do 1-2 sessions for recovery and cardiovascular health.
Don't turn everything into Zone 2. The biggest mistake is trying to stay in Zone 2 for every cardio session. Easy days should be truly easy. Hard days should actually be hard. The middle zone is where progress goes to die.
Track it properly. Use a heart rate monitor or smartwatch, or rely on the talk test. Don't just guess based on effort. Zone 2 feels easier than most people think, which is why they often train too hard.
The real benefits worth knowing about.
Stripped of the hype, Zone 2 training does offer legitimate benefits:
Improved endurance. Your body gets better at using oxygen efficiently. Easy efforts feel easier, which means you can work harder when it matters.
Enhanced recovery. Low-intensity cardio increases blood flow without adding significant fatigue. It's active recovery that actually works.
Cardiovascular health. Any sustained aerobic activity strengthens your heart and vascular system. Zone 2 is one way to achieve this, not the only way.
Fat oxidation. Your body does preferentially burn fat at lower intensities. But total fat loss depends on energy balance over time, not what fuel you use during one workout.
Mental break from intensity. Sometimes you just want to move without destroying yourself. Zone 2 fills that role perfectly.
Common mistakes to avoid.
Training in no-man's land. Most people accidentally train in Zone 3, which is too hard to sustain long efforts but too easy to drive meaningful adaptations. You end up tired without the benefits of either true Zone 2 or high-intensity work.
Neglecting intensity. If all your cardio is Zone 2, you're leaving massive gains on the table. Your cardiovascular system needs varied stimuli to improve.
Obsessing over perfect zones. Heart rate monitors aren't perfect. Environmental factors, stress, hydration, and fatigue all affect heart rate. Use zones as guidelines, not gospel.
Skipping it entirely because of the controversy. The research doesn't say Zone 2 is bad. It says it's not magic and probably shouldn't be your only cardio approach.
The bottom line on Zone 2.
Zone 2 cardio works. It's just not the miracle training method social media makes it out to be.
For most people with limited training time, a mix of intensities produces better results than pure Zone 2 work. That means including some harder efforts in your weekly routine alongside easier sessions.
But if you enjoy Zone 2, if it fits your schedule, if it helps you stay consistent, then it absolutely has a place in your training. Just don't feel like you're missing out if you prefer intervals or can't stomach hour-long steady-state sessions.
The best training plan is the one you'll actually follow. Whether that includes Zone 2 or not is up to you.
Now get moving. Your VERVE cardio gear is waiting.
