Fjell: Norwegian 4x4 Intervals

Climb four peaks. Fjell coaches the Norwegian 4x4 by your heart rate: four rounds of 4 minutes at 90 to 95 % of your max heart rate, with 3 minutes of easy recovery between them. Afterwards your heart rate draws every round as a peak. Fjell is Norwegian for mountain. KNOW BY MINUTE TWO During every work interval, Fjell’s halfway check watches how fast your heart rate climbs and tells you whether you will reach your zone by the 2:00 mark: “On pace · 5 bpm to go by 2:00” or “Behind · 9 bpm to go by 2:00”. Once you are in, it tells you how long that took: “In zone after 0:52”. The halfway check is Fjell’s own rule of thumb, built on how oxygen uptake catches up at the start of a hard interval. It expects your heart rate to level off, not climb in a straight line. COACHED BY YOUR HEART RATE • Live heart rate from Apple Watch against your zone: green in the zone, amber above it, with arrows that tell you to push or ease off. • Hear where you are: a chime and “In zone” when you reach the zone, and “Above zone” or “Below zone” when you leave it. • Voice cues and beeps, even with the screen locked: a 10-second heads-up, a 3-2-1 countdown and the round. Your music dips while Fjell speaks and podcasts pause, then both come back; you can turn that off. • A Live Activity on the lock screen and in the Dynamic Island with the time left, your heart rate and a pause button. • Taps on Apple Watch: a soft heads-up 10 seconds before each change, a distinct tap as it happens, and in work rounds a tap when you reach the zone, go above it or drop below it. Apple Watch keeps to your plan even while your iPhone is asleep. • Zones from your own max heart rate: your best 30-second heart rate in Apple Health, the age formula 208 − 0.7 × age when there is none, or a number you set. If your hardest 30 seconds beat it, the recap offers the new number in one tap. SEE EVERY ROUND • A recap of the whole session: every round as a peak, all rounds on one chart, and your minutes in zone, above and below. Each round shows its time to zone, ramp and time back into recovery, and your quickest round is marked, or “Best yet” when it beats every earlier session like it. • Over time: minutes in zone, time to zone and time back into recovery across your last 8 sessions like this one. • History and streaks that count only finished 4x4 sessions. • See how you recover from each session: your overnight heart rate variability against your own baseline. • Make it yours: rounds, interval lengths, zones and the halfway point are all adjustable. Run, walk uphill, cycle, row, ski or climb stairs. WORKS WITH APPLE HEALTH With your permission, Fjell reads your heart rate, heart rate variability, sleep and date of birth from Apple Health to set your zones and show your recovery. It saves your interval workouts to Apple Health. PRIVATE BY DESIGN No account. No ads. No analytics. No tracking. Your data stays on your iPhone and in Apple Health. NO APPLE WATCH? Choose Timer only for voice cues, beeps and the countdown without heart rate. Apple Watch adds live heart rate, the halfway check, the zone chime and taps on your wrist. The 4x4 is hard. If you have a heart condition or other health concerns, talk to a doctor first. Fjell is not medical advice. SUBSCRIPTION New subscribers get a 7-day free trial. After that, Fjell costs 2.99 USD a month or 19.99 USD a year. Prices vary by country. Payment is charged to your Apple Account when you confirm the purchase, or when the free trial ends. Your subscription renews automatically unless you cancel it at least 24 hours before the end of the current period. Manage or cancel it any time in Settings. Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Privacy Policy: https://fjell4x4.com/privacy