Z2/4×4 Trainer vs Buddies

Z2/4×4 Trainer turns the two most effective endurance methods — easy Zone 2 base work and high-intensity Norwegian 4×4 intervals — into a simple daily plan built around YOUR heart rate. WHAT YOU GET • Daily and weekly Zone 2 prescriptions at 60–70% of your max heart rate to build your aerobic base. • Norwegian 4×4 sessions: four 4-minute intervals at 85–95% of max heart rate, with 3-minute recoveries — the protocol used to boost VO2 max. • Weekly health-maintenance and weight-loss targets to keep you consistent. • Personalized zones from your max heart rate (220 − age), which you can override if you know your true max. WORKS WITH APPLE HEALTH • Pull in your heart rate, resting heart rate, active energy, body weight, and past workouts — or enter everything manually. Your choice. • Completed Zone 2 and 4×4 workouts are saved back to Apple Health so all your training lives in one place. IPHONE + APPLE WATCH • Plan and review on iPhone; train with your zones on your wrist. PRIVATE BY DESIGN • 100% on-device. No account, no sign-up, no server. • Nothing you enter or that we read from Apple Health ever leaves your device. • No ads, no analytics, no tracking, no third-party SDKs. • Your Health data is never used for advertising — ever. WHO IT'S FOR • Runners, cyclists, rowers, and anyone doing cardio who wants structure instead of guesswork. • Beginners building a base and experienced athletes adding VO2-max work. FREE + AN OPTIONAL ONE-TIME UPGRADE • Everything above is free: guided workouts on iPhone and Apple Watch, plans, zones, Apple Health sync. • One optional one-time purchase (Pro) unlocks the deeper coaching analysis: full readiness breakdown, overtraining guard, adaptive weekly progression, VO2-max trend, and CSV/JSON export. No subscription. Z2/4×4 Trainer is a fitness and training tool, not a medical device. It does not diagnose, treat, or prevent any disease. Talk to a healthcare professional before starting a new exercise program.

Little routines. Lovely company. Buddies brings a friendly face to your everyday care. Give each daily routine a buddy, choose your times, and check in as you go. From a morning walk to a water break or a moment of calm, your buddies are there for the little things. MAKE EACH ROUTINE YOUR OWN Choose from 25 buddy characters. Name your routine, add a note, and schedule it one to four times a day. Special buddies run, read, stretch, sip, and more when you check in. MEET YOUR BUDDIES Browse the buddy library, filter by Everyday, Special, or In use, and explore each buddy's story and moods. See the routines each buddy looks after. SEE YOUR DAY AT A GLANCE Today brings your routines together in a simple list or a playful buddy view. See what is coming up and what you have already logged. A GENTLE NUDGE Set local reminders for your scheduled times. Adjust dose reminders, hungry alerts, and sound and haptics in Me. LOOK BACK ON YOUR PROGRESS Explore your history calendar, daily records, and streaks. See what you logged and when. Changing a routine's name or schedule keeps its earlier records intact. START WITHOUT AN ACCOUNT Your routine records are stored on your device. No sign-in is needed, and your daily tracking works offline. A little care for yourself. A little company along the way. Buddies is a tracking and reminder tool. It does not provide medical advice, diagnosis, or treatment.