Strava or Apple Health: which one should your AI read?
Strava now has an MCP connector for ChatGPT and Claude, and so does Apple Health, through HealthSync, which I build. Weigh what follows accordingly. To keep it honest, I asked both the same questions about the same workouts, on the same day, with the same account: my first triathlon and an interval session. Here is what each one returned.
Test 1: a triathlon
I raced the Ventouxman sprint triathlon on September 19 with my Apple Watch in multisport mode. Asked for that day, the two connectors returned:
| Strava connector | HealthSync | |
|---|---|---|
| The watch's recording | One "Workout" of 1:22:44, with 0 m of distance and a speed of zero throughout | One multisport workout of 1:22:44 |
| Disciplines | None: no swim, no ride, no run | Five legs in order: swim, T1, bike, T2, run |
| Transitions | Absent | T1 2:47, T2 1:17, each with its heart rate |
| Per-leg detail | Heart rate for the whole race, nothing per discipline | Per leg: distance, heart rate, strokes for the swim, power and running form for the run |
That's Strava itself, not only its connector: the Apple Watch's triathlon lands there as a generic workout with no distance and a heart rate curve, nothing else. To get a swim, a ride and a run on my profile, I split the race by hand with an online tool and uploaded three files; the connector then lists those as three activities with no link between them and no transitions. An assistant reading Strava can't tell you that T1 cost a minute and a half more than T2. Here's what it can say when the race is whole, and how to get one GPX per leg without the online tool.
Test 2: an interval session
On October 9 I ran a descending set of 1 km, 800 m, 600 m and 400 m reps. From the Strava connector I requested every stream it offers for that run, cadence included. It returned heart rate, power, speed and distance; no cadence came back. Its list of stream types has no stride length, vertical oscillation or ground contact time at all. HealthSync returned the step count, which gives cadence, and all three of those, for the whole run and for each rep. So I could ask:
Did my running form fall apart on the last reps today?
healthsync · get_workout 19 legs · runningGroundContactTime · runningVerticalOscillation
No, it tightened. Ground contact time went from 221 to 226 ms on the 1 km and 800 m reps to 212 and 217 ms on the 600s, then 207 and 210 ms on the 400s. Vertical oscillation stayed between 9.2 and 9.8 cm on every rep. Shorter contacts at a steady bounce is what faster running looks like when form holds; there's no sign of the late-session shuffle.
It is the question I most want answered at the end of a hard session, and through Strava's connector there's nothing to answer it with.
Test 3: recovery
The Strava connector reads activities, their streams and laps, your profile, zones, gear, clubs and training plan. It has nothing for what happens between workouts: heart rate variability, resting heart rate, sleep, VO2 max. HealthSync syncs those from Apple Health every day, so "am I recovered from Sunday's race?" has an answer.
Where Strava is the better source
- Segments and best efforts. For the same interval run, Strava returned my fastest 400 m, kilometre, mile and 5K inside it, and my times on two local segments. That's Strava's own data, and Apple Health has none of it.
- Devices that never touch Apple Health. If you record on a Garmin or a bike computer and never sync to Apple Health, Strava is where your data is.
Which one should your AI read?
| Strava connector | HealthSync | |
|---|---|---|
| Triathlon as one race with transitions | No | Yes |
| Cadence | Not returned in our test | Yes, from the step count |
| Stride length, vertical oscillation, ground contact time | No | Yes |
| HRV, resting heart rate, sleep, VO2 max | No | Yes |
| Segments, best efforts, kudos | Yes | No |
| Workouts recorded outside Apple Health | Yes | No |
If your workouts start on an Apple Watch, read them from Apple Health: that's where they're whole. If they start on a Garmin and live on Strava, Strava's connector is the honest choice. And if your plan allows more than one connector, you can add both and ask each for what it does best.
Try it on your own workouts
HealthSync is on TestFlight now and on the App Store soon. Leave an address and we'll send the link.