Improve Your VO2 Max
Test where you stand, then train with guided intervals like the Norwegian 4x4.
An interval training app for iPhone and Apple Watch.
I improved my VO2 max from 41 to 50 in under a year! Highly recommended!
What users say
It's hard to find a good app to help you with workouts and motivate you to keep your body healthy. This one is perfect.
I started slowly improving my VO2 max and I'm very happy with the results that I achieved so far. Great app.
I don't need to improve my VO2 max actually, but this app really helps me to maintain it and holds me accountable.
I had no idea how to improve my VO2 max. It really helped to understand it and improve it.
Why PEAKVO2 is different
An interval training app for iPhone and Apple Watch, built around VO2 max.
- iPhone and Apple Watch. Every session runs with full-screen color-coded phases, a haptic tap, and a spoken audio cue at each transition, so you never watch a timer, and it runs on your Apple Watch too.
- Validated protocols, ready to run. Sixteen science-backed workouts are built in, including the Norwegian 4x4, Tabata, and REHIT, each with automatic warm-up, work, and recovery phases.
- Built around VO2 max. The protocols target your aerobic engine, and the app tracks your VO2 max trend over time so you can see the number move.
- Test and train in one place. Built-in field tests like the beep test and Cooper test estimate your VO2 max; the same app runs the interval workouts that raise it.
Pick your protocol
- REHIT 2x2012 min
- Tabata Protocol12 min
- Norwegian 4x436 min
- HIIT 30/3018 min
- Norwegian 3x326 min
- Marten's 6x338 min
- 6x2 Hill Intervals42 min
- Track 400m Intervals47 min
- Plus 8 more and a custom workout builder
You always know what phase you're in
The entire screen changes color.
See your training add up
- VO2 max trend
- Watch your estimated VO2 max climb as you stay consistent week after week.
- Year in review
- A heatmap of every session. Gaps are obvious. Streaks are satisfying.
- All your workouts count
- PEAKVO2 tracks sessions from other apps too, so your full training volume shows up in one place.
Free training tools
Calculators and timers, right in the browser. No signup.
From the blog
VO2 Max by Age
VO2 max chart by age and sex, what counts as a good score for each decade, and how to compare against elite athletes.
How to Improve VO2 Max
Every proven method to raise your VO2 max. HIIT protocols, zone 2 training, strength work, nutrition, recovery, and realistic timelines.
Norwegian 4x4 Protocol
The most researched HIIT protocol for improving VO2 max. Exact intervals, heart rate zones, science, and training plan.
Zone 2 Training Guide
The complete guide to zone 2 training. Heart rate zones, sample workouts, the science of aerobic base building, and why it matters for VO2 max.
Heart Rate Zones Explained
The five HR zones, your max heart rate, and the target HR for the work and recovery phases of HIIT, Tabata, and the 4x4.
Tabata Workouts Guide
The complete guide to Tabata training. 6 workouts, a 4-week plan, the original 1996 study, and how to get the most out of 4 minutes.
HIIT Workout Plan
A structured 6-week HIIT plan, three sessions a week, from a gentle on-ramp to the Norwegian 4x4. Exact sessions and heart rate targets.
Beep Test Score by Age
Average and good beep test levels for men and women by decade, youth PACER standards, and the VO2 max each level represents.
VO2 Max Test Guide
What to expect at a VO2 max lab test. Preparation, protocols, costs, results, and how lab tests compare to wearable estimates.
Find a VO2 max testing lab
Browse our curated directory of independent testing labs worldwide. PEAKVO2 is a training app and does not provide the testing itself.
Browse all cities →
Test your VO2 max first
BeepRunner runs the official 20m beep test and Cooper test on your iPhone — with instant VO2 max estimation.
Made by someone who actually uses it
I'm Cristian, the developer of PEAKVO2. I built it because I was doing the Norwegian 4x4 myself and wanted the timing handled on my wrist. I took my own VO2 max from about 41 to 51 with it, first running, then on the bike.
Read how I did it →Frequently asked questions
What is PEAKVO2?
PEAKVO2 is an interval training app for iPhone and Apple Watch used by runners, cyclists, and endurance athletes to improve their VO2 max. It includes science-backed protocols like the Norwegian 4x4, Tabata, HIIT 30/30, REHIT 2x20, Norwegian 3x3, and more, with automatic phase transitions and real-time guidance on your wrist.
Does PEAKVO2 test my VO2 max?
PEAKVO2 estimates your VO2 max with proven field tests like the Beep Test, Cooper Test, 1.5 Mile Run and Rockport Walk Test, no lab or spirometry needed. It does not offer lab, metabolic or medical testing; for a lab test, see our directory of independent VO2 max testing labs.
What interval protocols does PEAKVO2 include?
PEAKVO2 includes 16 built-in workouts: Norwegian 4x4, Norwegian 3x3, Tabata Protocol, HIIT 30/30, REHIT 2x20, Marten's 6x3, 5x3, 8x2, 10x1, and 4x5 Intervals, 15x 45s/15s, 6x2 Hill Intervals, 3x8 Combo Intervals, Fartlek 20s/10s/10s, Track 400m Intervals, and Over-Under Intervals, plus a custom workout builder. Each workout has built-in warm-up, work, and recovery phases.
What's the best app for VO2 max interval training on Apple Watch?
PEAKVO2 is built specifically for VO2 max interval training on iPhone and Apple Watch. Full-screen color-coded phases tell you whether you're in warm-up, work, or recovery, with automatic transitions and haptic alerts so you never miss a cue, and the same session runs on your Apple Watch.
Is there an app for Norwegian 4x4 interval training?
Yes. PEAKVO2 includes the full Norwegian 4x4 protocol, four 4-minute high-intensity intervals at 90-95% max heart rate, each followed by 3-minute active recovery, with warm-up and cool-down built in. The app handles all the timing so you just run.
Is PEAKVO2 free? How much does it cost?
PEAKVO2 gives you 4 workouts free (REHIT 2x20, Tabata Protocol, HIIT 30/30, Norwegian 3x3). Unlocking all 16 workouts and every feature costs $0.99 per month, $8.99 per year, or $17.99 once for lifetime access (US prices).
How does PEAKVO2 help improve my VO2 max?
PEAKVO2 guides you through research-backed high-intensity interval protocols that are proven to increase VO2 max. The app handles all the timing, automatic phase transitions, haptic alerts, and color-coded screens, so you can focus entirely on effort. It also tracks your VO2 max trend over time so you can see your progress.
Can older adults use PEAKVO2 to improve VO2 max?
Yes. VO2 max is one of the strongest predictors of longevity, and improving it matters at any age. PEAKVO2's protocols are based on percentage of your max heart rate, so intensity scales naturally to your fitness level. The Norwegian 4x4 protocol in particular has been studied in older populations and shown to significantly improve cardiovascular fitness. As with any high-intensity training, consult your doctor before starting.