How It Works
RunIntensity reads your Apple Health data and calculates what other apps miss.
Stress-Adjusted Miles
A 5-factor model that accounts for heart rate intensity, terrain, surface type, cumulative fatigue, and environmental stress. See the real cost of every run.
Daily Readiness Score
Composite score from HRV, sleep quality, resting heart rate, and prior workout load. Know if today is a push day or a recovery day.
Weekly SAM Budget
Plan your week with a target training load. Track actual vs. planned as you go with mid-week pacing tips and same-day comparisons.
Free Features
Everything you need to train smarter. No account required.
5-Factor SAM Model
Heart rate intensity, terrain elevation, surface type, cumulative fatigue, and environmental stress combined into one number.
Training Planner
Build periodized plans with phases (base, build, peak, taper, recovery) and milestones for race goals.
Body Soreness Tracker
Tap 36 anatomical regions on a 3D body model to log soreness and spot patterns before they become injuries.
Personal Records
Automatic tracking of distance PRs, fastest paces, and max intensity efforts with 30-day badges.
Research & Science
Read the peer-reviewed studies behind every calculation. No black boxes.
Works with Any Watch
Apple Watch, Garmin, COROS, Strava — import workouts via Apple Health or connect directly. No data left behind.
Apple Watch Companion
Race Pace interval timer, guided workouts, and live metrics on your wrist.
Race Pace Timer
Build custom interval timers with exact H:M:S durations and per-timer repeats. Your last preset is saved automatically for one-tap race starts.
Planned Workouts
Workouts you create on the iPhone sync to the Watch automatically. Each segment has a countdown ring with haptic cues at every transition.
Live Metrics
Heart rate, pace, distance, and elapsed time in real time. Swipe between countdown, controls, and metrics during any workout.
Connect Your Favorite Apps
Import workouts directly from Strava, Garmin, and COROS — no Apple Health required.
Strava
Connect your Strava account and your activities import automatically with distance, pace, heart rate, elevation, and GPS routes.
Garmin Connect
Link your Garmin account for automatic activity sync. All your Forerunner, Fenix, and Enduro data flows straight in.
COROS
Connect your COROS account to import workouts from your PACE, APEX, or VERTIX watch automatically.
Duplicate workouts from multiple sources are automatically detected and merged — no double-counting.
Go Further
Optional subscriptions for social runners and coaches.
Friends Mode
See how your friends are training.
- View friends' readiness scores
- Browse SAM charts & workout history
- See personal records & soreness
- Training phases & milestones
- Connect via search or invite
Coach Mode
Full athlete and team management.
- Everything in Friends Mode
- Manage unlimited athletes & groups
- Create phases, milestones & plans
- Assign planned workouts
- Group comparison charts
- Push notifications on athlete activity
- Web Coach Dashboard — manage from any browser
Privacy First
All core calculations happen on your device. RunIntensity reads Apple Health data but never writes to it. Friends and Coach modes sync only the data you choose to share to a secure Azure backend. No ads. No analytics SDKs in the app. No tracking.
Read the full Privacy Policy →Requires iPhone with iOS 17.0 or later. Apple Watch Series 4 or later for companion app. Import workouts via Apple Health, Strava, Garmin Connect, or COROS. Sign in with Apple required for Friends Mode, Coach Mode, and connections.