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 for the 2:00 check” or “About 6 bpm short of the zone at 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. 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. • Voice cues and beeps over your music or podcast: a 10-second heads-up, a 3-2-1 countdown and the round. Your audio keeps playing, also with the screen locked. • A Live Activity on the lock screen and in the Dynamic Island with the time left, your heart rate and a pause button. • Haptics on Apple Watch before every change. • 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. SEE EVERY ROUND • A recap of the whole session: every round as a peak, with time in zone, time to zone and your ramp. • 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 and haptics. 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