If you’ve ever wanted a clear, data-driven way to see how your fitness is improving, VO₂ Max is one of the most powerful metrics you can track.
And if you own an Amazfit T-Rex 3, you already have this feature on your wrist — ready to tell you exactly how well your body uses oxygen during intense exercise.
I’ve been running with the T-Rex 3 for a while now, and VO₂ Max has become one of my favorite training tools. It’s not just a number — it’s a window into my endurance, my heart health, and how my training is paying off.
Here’s my complete, experience-based guide to getting accurate VO₂ Max readings on the T-Rex 3, and how to make sense of them.
What VO₂ Max Means
VO₂ Max is essentially your aerobic ceiling — the maximum amount of oxygen your body can use during hard exercise.
The higher your score, the more efficiently your muscles use oxygen, which usually means better stamina and performance.
For runners, hikers, and endurance athletes, knowing your VO₂ Max can help you:
- See how your fitness is trending over time
- Adjust your training so you’re not overdoing it (or undertraining)
- Understand how your heart, lungs, and muscles work together
I think of it as my personal “engine size” — the bigger and more efficient it is, the longer and faster I can go.
Meet the Amazfit T-Rex 3
The T-Rex 3 isn’t just rugged and outdoorsy-looking. Under the hood, it has GPS, multiple running modes, continuous heart rate tracking, and — most importantly here — VO2 Max estimation.
Pair it with the Zepp app, and you get a history of your runs, fitness trends, and progress charts.
I’ve found that the more consistently you use it, the clearer your VO2 Max patterns become.
How to Get VO2 Max on Amazfit T-Rex 3 — Step By Step Guide
Step 1: Set Up Your Data Correctly
Your T-Rex 3 gets VO₂ Max estimates by combining sensor data with the personal stats you enter in the Zep app.
If your age, weight, height, or gender are wrong, your readings will be off.
In the Zep app:
- Tap your profile.
- Double-check your age, weight, height, and gender.
- Save changes.
I once left an old weight in there for months and wondered why my VO₂ Max looked unusually high. Turns out, the watch thought I was lighter than I was — lesson learned.
Step 2: Choose the Right Running Mode
VO₂ Max isn’t tracked during just any activity. On the T-Rex 3, you’ll need to use one of these running modes:
- Outdoor Running
- Playground Running
- Cross-Country Running
- Ultramarathon
Once you’ve picked your mode, start your run. As long as you meet the pace and heart rate requirements, the watch will calculate VO₂ Max automatically.
Step 3: Hit the Required Pace and Distance
To get a valid reading, you need to:
- Maintain at least 6 km/h (3.7 mph)
- Run 10 km without too many stops
This ensures the watch collects enough consistent data. If you run too slow, stop too often, or cut your distance short, the VO₂ Max reading might not trigger.
I recommend planning your route so you can keep a steady pace without traffic lights or tricky terrain breaking your rhythm.
Step 4: Stay in the Right Heart Rate Zone
VO₂ Max is all about aerobic performance, so your heart rate needs to be at least 75% of your max during the run.
That means you’re working hard enough to stress your system, but not so hard that you burn out in the first mile.
Tips I use to stay in range:
- Warm up for at least 10 minutes before hitting pace
- Use the watch’s heart rate alerts so I don’t drift too low
- Pace myself instead of sprinting early
Step 5: Check Your Data — During and After the Run
While running, you can swipe to see your current VO₂ Max estimate alongside your heart rate, pace, and distance. After your workout:
- On the watch: Check your workout history for your highest VO₂ Max from that session.
- In the Zep app: View your VO₂ Max trends, compare runs, and spot improvements over weeks or months.
I love checking my charts after a month of consistent training — it’s like proof that the early mornings and long runs are working.
What the Number Means
- Higher number = better endurance and cardiovascular health
- Lower number = either you’re tired, need recovery, or have room to improve
Over time, you’ll start to notice patterns. For example, mine goes up after a few weeks of consistent training and drops when I’m short on sleep.
Common Problems (and How to Fix Them)
| Problem | Likely Cause | Quick Fix |
|---|---|---|
| No VO2 Max reading | Didn’t meet speed/distance/heart rate requirements | Pick a flat route and pace yourself |
| Heart rate spikes/drops | Strap too loose or bad contact | Tighten strap; wear above wrist bone |
| GPS errors | Tall buildings or trees blocking signal | Choose open routes; wait for GPS lock |
| Data won’t sync | Bluetooth or app glitch | Refresh Zepp app, reconnect watch |
My Tips for Getting Consistent Readings
- Run in similar conditions each time (same time of day, similar terrain) so your data is comparable.
- Stay hydrated and rested — dehydration or fatigue can lower your VO₂ Max temporarily.
- Fit your watch snugly so the heart rate sensor works accurately.
And remember, one bad reading doesn’t mean your fitness has suddenly dropped. Look for trends, not one-off numbers.
Why I Keep Tracking VO₂ Max
For me, VO₂ Max isn’t about bragging rights — it’s about seeing progress I can’t always feel day-to-day.
Some weeks, my legs feel heavy, but my VO₂ Max still edges upward. That tells me my training is building long-term endurance even if I have off days.
If you’ve got a T-Rex 3, I highly recommend making VO₂ Max part of your training routine. It’s like having a sports scientist on your wrist, constantly measuring how your “engine” is performing — and helping you figure out how to make it stronger.
Also See:-
- Is the Amazfit T-Rex 3 Ultra on the Horizon? Everything We Know So Far.
- How I Use Komoot and My T-Rex 3 Watch for Hiking and Biking.
- Amazfit T-Rex 3 Features That Help You Own the Trail.
- Rod Farvard Joins Amazfit: A Bold Step Toward Pro-Level Fitness Tech.
- New Amazfit T-Rex 3 Update 3.9.4.4: HYROX Mode, Map Zoom & More!
