Apple Watch's Workout Buddy feature, launched with watchOS 26 in September 2025, uses Apple Intelligence to analyze a user's real-time workout data and fitness history and deliver personalized, spoken motivational coaching during exercise sessions. The voice is generated by a custom text-to-speech model trained on Fitness+ trainer voices.

Workout Buddy analyzes data including heart rate, pace, distance, Activity ring progress, and personal fitness milestones during a workout session to produce contextual spoken feedback — such as encouragement when the user reaches a new milestone or a pacing reminder based on their history. A custom text-to-speech model converts these insights into audio using voice data from Fitness+ trainers. The feature requires Bluetooth headphones and an Apple Intelligence-compatible iPhone nearby. Initial support covers outdoor and indoor running, walking, cycling, HIIT, and strength training. The feature launched first in English, with additional languages expected later.