Ramp4x4: VO2 Max Trainer

Train your VO2 max with guided Norwegian 4x4 interval workouts on iPhone and Apple Watch. Four 4-minute efforts. Three-minute recoveries. Live heart-rate guidance. Ramp4x4 handles the timing and coaching so you can focus on the workout. START WITH A PLAN Choose your goal, preview a session, and set an optional reminder for your first workout. Start unlimited classic 4x4 sessions for free, or follow a guided Premium 8-week plan with two workouts per week. STAY IN YOUR TARGET ZONE See when your heart rate is below, within, or above your target. Follow interval countdowns, voice cues, and haptics on iPhone or Apple Watch. Use Apple Watch, a compatible Bluetooth heart-rate monitor, supported heart-rate earbuds, or Timer Only. TRAIN WHERE YOU LIKE Run outdoors, or do your intervals on a treadmill, bike, rower, elliptical, stair climber, or SkiErg. Your warmup, four hard efforts, recoveries, and cooldown are ready with one tap. SEE HOW YOU PERFORMED Review completed intervals, time in your target heart-rate range, high-intensity time, and recovery. Premium adds full workout history, detailed interval breakdowns, quality scoring, comparisons, and coaching insights. TRACK CARDIO FITNESS See your latest available VO2 max estimate from Apple Health. Premium shows available Cardio Fitness history alongside workout trends. Ramp4x4 displays Apple Health estimates; it does not directly measure VO2 max. Indoor workouts do not generate Apple Watch Cardio Fitness estimates, and a new estimate is not guaranteed after every outdoor workout. FREE • Unlimited classic Norwegian 4x4 workouts • Apple Watch workouts, voice cues, and haptics • Live coaching with a supported heart-rate source, or Timer Only • Apple Health workout saving • Latest available Cardio Fitness estimate and workout summary PREMIUM • Guided 8-week training plan • Full workout history and detailed interval analysis • Heart-rate, recovery, and workout-quality insights • Available Cardio Fitness trend history and comparisons • Custom interval presets Heart-rate features require a supported source. Apple Health features require permission and available data. Ramp4x4 is for general fitness and wellness, not medical advice. Build up gradually and speak with a clinician before near-maximal intervals if you have a health concern. Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Privacy Policy: https://rampworkout.com/privacy/