If you want your tracker’s heart rate to show up somewhere else — a Peloton, a bike computer, a rowing erg, a training app — the tracker has to broadcast on the standard Bluetooth heart-rate profile, the same open protocol chest straps have used for years. Some trackers do. Some don’t. And the ones that do differ in ways no spec sheet prints.
We build software that reads this broadcast, so we test these devices hands-on. Here is what we’ve verified.
The three questions that matter
Does it speak the standard profile at all? “Has Bluetooth” is not the same as “broadcasts heart rate.” Every tracker uses Bluetooth to sync with its own app; only some also broadcast on the open profile other software can read.
Does it broadcast outside workouts? Some devices treat broadcasting as a workout feature. If you want all-day reading — not just during a logged session — the broadcast has to run continuously, and vendor documentation usually doesn’t say whether it does.
How many connections at once? If the broadcast allows one reader at a time, your bike computer and any other listening app are rivals. Multiple connections mean they can share.
The straps, tested
| Device | Standard profile | Outside workouts | Simultaneous readers |
|---|---|---|---|
| Whoop 4.0 / 5.0 / MG | Yes | Yes | Multiple |
| Amazfit Helio Strap | Yes | Yes | Multiple |
| Google Fitbit Air | Yes | Yes | One third-party at a time |
| Garmin CIRQA | Documented by Garmin | Untested by us | Untested by us |
| Polar Loop | No broadcast to third parties | — | — |
“Yes” entries reflect our own hands-on testing, not spec sheets.
Whoop
Whoop calls it Heart Rate Broadcast — a toggle in the app’s device settings. Standard profile, continuous, multiple simultaneous readers, no ANT+. It can switch itself off after software or firmware updates, so re-check it after updates. Full details in our Heart Rate Broadcast guide.
Amazfit Helio Strap
Amazfit calls it heart rate push: in the Zepp app, open your device and look under Health Monitoring. Amazfit’s support page confirms it connects to third-party Bluetooth devices such as watches, cycling computers, and treadmills. In our testing the broadcast runs continuously outside workouts and accepts multiple simultaneous readers. Setup steps are in our Helio broadcast guide.
Google Fitbit Air
The Air broadcasts on the standard profile, and Google’s support pages document heart-rate sharing with equipment and apps like Peloton, Zwift, and Concept2. Two things our testing adds: the option that keeps the band visible to equipment and apps at all times lives in the Google Health app, and the Air accepts one third-party connection at a time — separate from Google Health’s own connection, so the band’s sync, steps, and sleep carry on regardless. Details in our Fitbit Air broadcast guide.
Garmin CIRQA
Garmin documents a broadcast toggle for the CIRQA and notes it costs battery. We haven’t tested one, so continuous behavior and connection count are unverified — the two questions spec sheets don’t answer.
Polar Loop
The Polar Loop does not broadcast to third-party equipment or apps. It pairs exclusively with Polar’s own app, and moving it to a different phone requires a factory reset. It is built as a closed loop with Polar’s ecosystem — a design choice, and one to know before buying it for broadcast use.
Chest straps and armbands
The dedicated class — chest straps and optical armbands from the likes of Polar, Scosche, COOSPO, and Chileaf — broadcasts continuously on the standard profile by definition; that is the product. The trade-offs are battery measured in hours rather than days, and on several models a manual power button, so they only broadcast when you remember to turn them on.
How do I choose a strap for broadcasting?
Before buying any tracker for its broadcast, ask the three questions — standard profile, outside workouts, how many readers — and expect to verify the last two yourself. The broadcast is also what brainful — the b-score app for Whoop straps — is built on: it listens to the standard profile and puts a b-score (0–100) on each calendar event, on the phone — what each hour was actually worth. It was built and tuned on Whoop; in our own testing the Helio Strap pairs and scores end to end today, and the Air’s broadcast is real and continuous — though we haven’t yet run the Air end to end in brainful. Official support for those two — including tuning for their optical stacks — hasn’t shipped yet, so early users are exactly that: early. If you own one, the door is open.
Sources: WHOOP Support, “Heart Rate Broadcast”; Amazfit Support, “How to set the heart rate push function?” (Helio Strap); Google Health Help, “Share your real-time heart rate with fitness equipment & apps”; Garmin’s published CIRQA documentation; Polar’s published Loop materials. Continuous-broadcast behavior and simultaneous-connection counts are from our own device testing, August 2026. Firmware updates can change any of this; re-verify on your device.