January 24, 2025: This is the biggest behind the scenes update in a long time. There are many internal changes to improve reliability, and as a bonus, MzFit now launches faster. If you’re new to MzFit, MzFit is an app for iPhone and iPad that lets you do YouTube workout videos. But better. Filter and search to find exactly the workout videos you’re looking for. No ads during your workouts. Apple Watch integration - automatically track your heart rate and calories during your workout.