Comparison

N4x4 vs Gregs Endurance Training

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

N4x4

This app guides you through the scientifically-backed Norwegian 4x4 HIIT protocol to efficiently boost your VO2 Max and cardiovascular health. It offers set-and-forget workouts with visual and audio cues, suitable for all fitness levels.

Highlights
  • Norwegian 4x4 HIIT protocol
  • Set-and-forget workout structure
  • Visual and audio interval cues
  • Real-time heart rate zone display
  • 5-minute warm-up
  • 4 rounds of 4-minute intervals
  • 3-minute recovery periods
Features
Read full description

The best Norwegian 4x4 App on the App Store. Train the Norwegian 4x4 without watching the clock or guessing your effort. N4x4 reads your live heart rate — from Apple Watch, AirPods Pro 3, Garmin, WHOOP, Polar, or any Bluetooth monitor — and turns it into clear push, hold, and ease-off cues through every interval. When you finish, you see exactly how long you held the target zone, and how today compared with last time. Four 4-minute efforts, three easy recoveries. 33 minutes, warm-up and cooldown included. It trains VO2 max, the fitness marker most closely tied to how well you age, and it's one of the most studied ways to raise it. If you're going to invest time in your health, this is a strong place to start. HIT THE RIGHT ZONE • Target zones calculated from your own max heart rate • The number turns orange when you're below the zone and red when you're above, on both iPhone and Apple Watch • Spoken and haptic nudges when you drift out and stay out • A haptic countdown into every interval change: two taps, then the buzz USE THE SENSOR YOU ALREADY OWN • Apple Watch: install N4x4 on your wrist and heart rate streams automatically • AirPods Pro 3: the earbuds you're already wearing double as your heart rate monitor (iPhone on iOS 26) • Garmin (Broadcast Heart Rate), WHOOP (HR Broadcast), Polar, Wahoo, COROS, Powerbeats Pro 2, and any standard Bluetooth chest strap or armband • Wearing more than one? You choose which source wins • A built-in guide with exact, per-model setup steps EASY TO KEEP THE HABIT • Voice coaching through every interval, with the phone locked and your music ducked • Night-before, morning-of, and comeback reminders — each on its own switch • Weekly streaks, and a Live Activity on the Lock Screen and Dynamic Island FINISH WITH PROOF • Every interval charted against its target zone • Time in zone, time to zone, and a note per interval for your settings • Last session laid over today's, so progress is easy to see • Your usual workout — Cycle, Run, Kettlebells, and more — pre-selected when you save SEE THE PAYOFF • Your VO2 max trend from Apple Health • Training calendar, milestones, and full session history Works on the treadmill, rower, bike, stair climber, with kettlebells, or on the open road — any cardio that gets your heart into the zone. No account. No subscription. No ads. Your data stays on your device and in Apple Health. Start with one hard session a week. Add a second when you're ready.

About

Gregs Endurance Training

Features
Read full description

GET FIT is a training platform built by a working endurance coach — not a content library. Every plan is written the way a coach actually programs: paced from YOUR benchmarks, structured week by week, and honest about recovery. TRAIN FOR WHAT'S NEXT - Running: 5K, 10K, half marathon, and marathon plans built around three quality days a week - Triathlon: Sprint, Olympic, 70.3, and full-distance plans — swim, bike, run, and the strength work that survives race week - Strength: a classic 5/3/1 cycle, four lifts, four weeks - Swimming: focused technique-and-speed blocks PACED FROM YOUR NUMBERS Enter your 5K time, your lift maxes, your swim splits — every workout's targets are computed from your own benchmarks, not generic zones. Test, train, retest, improve. SEE YOUR PROGRESS Personal records with baseline-to-current tracking, bodyweight trends, and a calendar that shows exactly what's done and what's coming. CONNECT YOUR TRAINING Optional Strava connection matches your real activities to your scheduled workouts. Race-date plans schedule backward from your event so you peak on the right day. COACHED OR SELF-SERVICE Train independently on any plan, or connect with Coach Greg for full white-glove coaching with a code. Questions? Coach Greg answers his own email. Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

Screenshots

N4x44 screens
Gregs Endurance Training4 screens

Verdict

The call

The clearest difference is update cadence: N4x4 at every 3 days against Gregs Endurance Training's weekly. N4x4 also leads on iOS requirement (17.5 vs 26.4). On price, ads, in-app purchases and device support there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

N4x4 ships an update every 3 days, Gregs Endurance Training weekly. The most recent releases landed on October 4, 2026 and October 5, 2026 respectively.

Scorecard2 real differences · 8 level
N4x4 versus Gregs Endurance Training: the parameters behind the verdict, then further details
ParameterN4x4Gregs Endurance Training
PriceFreeFree
Rating4.4 (17 ratings) — better—
Positive reviews66.7% of reviews—
Number of ratings17 — better—
Update frequencyEvery 3 days — betterWeekly
AdsNoNo
In-app purchasesNoNo
MonetizationFree—
DevicesiPhone, Apple Watch — betteriPhone
Requires iOS17.5 — better26.4
Further details — not scored
Size15 MB4 MB
Age rating4+4+
DeveloperJan van RensburgPin Oak Partners LLC

In-app purchases

None

N4x4

No in-app purchases

None

Gregs Endurance Training

No in-app purchases

Questions

Is N4x4 free?
N4x4 is free to download, with no in-app purchases.
Is Gregs Endurance Training free?
Gregs Endurance Training is free to download, with no in-app purchases.
Do N4x4 or Gregs Endurance Training have ads?
Neither N4x4 nor Gregs Endurance Training shows ads.
Which is updated more often, N4x4 or Gregs Endurance Training?
N4x4 ships an update every 3 days, and Gregs Endurance Training weekly. Most recently, N4x4 was updated on October 4, 2026 and Gregs Endurance Training on October 5, 2026.

Other comparisons