Norwegian 4x4 Coach

Norwegian 4x4 Coach guides you through the proven Norwegian 4x4 interval workout using your real heart rate, so you train at the right intensity instead of guessing. The session is simple and effective: a warm-up, four 4-minute work intervals at a hard effort, three recovery periods in between, and a cool-down. As you move through each phase, the app announces what's coming and gives short, infrequent spoken cues to push harder, hold steady, or ease off, based on your live and predicted heart rate. No staring at the screen, no over-coaching. FEATURES - Live heart-rate coaching with brief, well-timed spoken cues - Clear phase guidance: warm-up, 4x work intervals, recoveries, cool-down - Per-phase target heart-rate ranges, set as a percent of your max (e.g. 85%–95%) - Anticipates drift and nudges you before you fall out of range - Fully configurable: max heart rate, target ranges, phase durations, and the number of intervals - Choose the coaching voice from the voices installed on your device - Put the cues in your own words: customize every effort prompt and phase announcement in Settings - Keeps coaching with the screen locked, and dips your music or podcast only while a cue is speaking - Works with Bluetooth heart-rate sensors, including Polar H10, Verity Sense, and OH1, and standard Bluetooth chest straps - Export a full session (heart rate over time, the phase and round, and target zones) to share with Messages, Mail, Files, or an AI assistant for analysis, as a self-documenting file or plain text - Optional nag mode: repeat a cue while you are still out of your target range (off by default) - Clean, distraction-free design PRIVACY Norwegian 4x4 Coach collects no data. Your heart rate is used only on your device, in real time, and is never stored off-device or transmitted. There is no tracking, no analytics, and no account. SAFETY Norwegian 4x4 Coach is a fitness tool, not a medical device, and does not provide medical advice. High-intensity exercise carries risk. Consult a physician before beginning any new exercise program, and stop if you feel unwell. Requires a Bluetooth heart-rate sensor.