What Norwegian 4x4 Protocol is
From the developer's own App Store listing, read on 3 September 2026. See the listing →
- Precision 4-minute work and 3-minute recovery cycles.
- Heart rate zone tracking against the 90–95% maximum target.
- Customisable warm-up and cool-down, with haptic feedback at each switch.
- Works offline, and covers running, cycling, rowing and other cardio.
- One purchase. No subscription.
Where NTRVL differs
They are cheaper if you stay more than a year.
$5.99 once against $9.99 a year. The first year we cost more by four dollars; after that they cost nothing and we keep charging. If a timer is all you need, they are still the better buy and we will not pretend otherwise.
We are built around a programme, not a session.
NTRVL schedules eight weeks — 24 sessions, three a week, the dose the research actually used — and shifts the plan when you miss a day. Their app times the session you decided to do.
Heart rate can come from your AirPods, your watch, or nowhere.
NTRVL treats AirPods Pro 3 as a first-class sensor, hands over to the watch if they come out mid-workout, and still runs the protocol if you have neither.
We track how fast your heart comes back down.
Heart rate recovery in the first minute after an interval improves in two to three weeks — long before VO₂ Max moves. It is the earliest honest sign the training is working, and NTRVL charts it over time.
When Norwegian 4x4 Protocol is the better choice
We would rather you use the right app than ours.
- You want a timer you own outright, with no subscription and no account.
- You already know the protocol, already have a watch, and want nothing between you and the intervals.
- You want an app with a two-year track record and real reviews. Theirs has 50 ratings at 4.3 stars; ours has none yet.
The numbers
| Fact | NTRVL | Norwegian 4x4 Protocol |
|---|---|---|
| Price | Free · Pro $1.99/mo or $9.99/yr, 7 days free | $5.99 once |
| On the App Store since | 16 May 2026 | 1 May 2024 |
| Latest version | 1.1 — 31 Aug 2026 | 2.5 — 10 Jun 2026 |
| Ratings | No ratings yet | 4.3 ★ from 50 ratings |
| Minimum iOS | iOS 17.0 | iOS 17.6 |
Every figure above was read from Apple's App Store listing data on 3 September 2026. Prices and versions change — check the store before you decide.
Verdict
If you want a 4×4 timer, buy theirs. Six dollars once is a fair price for a job well done, and we are not going to argue you out of it. Choose NTRVL when you want the eight-week programme, a recovery trend, and heart rate from whatever you happen to be wearing.
Try NTRVL freeThe free session is one interval, about twelve minutes, and it does not expire. No heart rate hardware required.