HIIT 4x4 Lite vs Go4 Tracker

HIIT 4x4 Lite is an Apple Watch exercise monitoring app for High Intensity Interval Training (HIIT). The app sequences exercise between high and low intensity intervals. The intensity of the exercise is measured as a percentage of your Maximum Heart Rate (MHR). The HIIT 4x4 intervals are as follows: - 10 minutes warmup at 60% MHR - 4 minutes high intensity at 90% MHR - 3 minutes low intensity at 70% MHR - repeat high-low intervals 4 times (4 high intensity intervals of 4 minutes each = 4x4). HIIT 4x4 Lite uses a speedometer type dial to display heart rate. When the arrow is in the green zone then your heart rate is within the interval target. If the heart rate later falls out of the target range, warning chimes are issued until back in range. Each person's MHR is different, and changes with age. A commonly used formula for MHR is 220 - age in years. A more accurate number can be discovered by using a heart monitor during all out exercise and observing the highest heart rate achieved. HIIT 4x4 Lite does NOT store your workout history using Apple Health. Please use the full version HIIT 4x4 (not Lite) to store workout history. HIIT 4x4 Lite is based on the High Intensity Interval Training 4x4 program developed by the Norwegian University of Science and Technology's Cardiac Exercise Group.

Go4 Tracker — Your Complete Outdoor Running & Workout Companion Go4 Tracker turns every run or workout into a detailed, easy-to-read record — from the route you took to the song that was playing when you hit your fastest lap. GPS Route Tracking with Heat Map See exactly where you ran on an interactive map, with a color-coded heat map (green to red) that shows where you sped up and where you slowed down — lap by lap. Detailed Lap & Split Analysis Every lap is automatically scored — Good, OK, or Bad — based on your pace, so you can instantly spot your strongest and weakest efforts. Kilometer splits and average pace are calculated automatically. Heart Rate Insights Pulled directly from Apple Health, see your maximum, minimum, and average BPM for the entire session, alongside your saved weight, height, and age for more personalized context. Live Weather & Location Data Go4 Tracker automatically fetches the temperature, "feels like" reading, humidity, pressure, and sky conditions at your exact location and workout time — so you always know the conditions you trained in. Workout Music Log Curious what you were listening to during that personal best? Go4 Tracker keeps a log of every song played during your workout, complete with artist and duration. Calendar History Browse a simple monthly calendar view marked with every day you worked out, and tap in to instantly pull up that day's full session details. Exercise Library Built-in illustrated guides for core, strength, and conditioning exercises — like hip raises, flutter kicks, and burpees — help you round out your training beyond just running. Backup, Restore & GPX Editing Never lose a workout again. Export all your records into a single zip file for backup, or export individual workouts as GPX files to clean up and fine-tune your routes with a GPX editor of your choice. Free up storage by backing up older workouts and removing them from your device, then restore them anytime you like. Full Workout Summary Total distance, duration, average pace, calories burned, start and end coordinates, and altitude changes are all saved automatically for every session. Whether you're training for a race, tracking a casual daily jog, or just curious about the conditions you exercised in, Go4 Tracker gives you the complete picture — route, effort, environment, and soundtrack — in one clean, easy-to-navigate app.