How to wear a heart rate chest strap

By Andreas B. Diendorfer · ORCID · LinkedIn · Updated 12 October 2026

Short answer

Moisten the electrode areas on the strap, wrap it snugly around your chest, click the sensor onto the strap, and check that the moist electrodes are against your skin. Rinse the strap after use. That is Polar's routine for the H10, and other straps are close.

Last checked: 12 October 2026.

The steps

Polar's manual for the H10 gives three, and its pairing guide adds a check.

Moisten the electrode areas. The two textured patches on the back of the strap. Water is enough.
Fasten the strap around your chest and adjust it so it fits snugly. Snug, not painful. A loose strap slips, and a slipping strap is the commonest cause of a reading that jumps.
Attach the connector to the strap.
Check the contact. The moist electrode areas should sit firmly against your skin, and Polar's guide says the logo of the connector should be central and upright.

Then give it a few seconds. Most sensors only start sending once they can feel a heartbeat. See how to connect a Bluetooth monitor.

Where on the body

Maker manuals place a chest strap around the chest. Where exactly differs by brand, so check yours. Beatcast doesn't care where a sensor sits. An arm band or a strap worn elsewhere works if it reads. See the sensor table.

Moisture

A dry strap reads nothing or jumps. If it drops out early in a session, wet the electrodes again. In cold weather or on dry skin this happens more.

After you finish

Polar says to detach the connector and rinse the strap under running water after every use. Leaving the strap wet can keep the sensor on and wear the battery down. Follow your maker's washing advice for the rest.

All-day wear

Makers design straps for sessions, not for a day. Check your manual before you wear one for hours. We make no claims about skin comfort.

If it still doesn't read

Look at the battery, the contacts and the fit, in that order. The checklist takes it from there.

Where Beatcast fits

Once the strap sends, Beatcast shows the number in zone colour, in the Dynamic Island and on the Lock Screen. A sensor is required. Beatcast on the App Store. Fourteen days free, then one purchase.

Questions

Do I wear the strap on bare skin?

Makers say the electrodes need skin contact.

How tight should it be?

Snug enough not to slip.

Do I wet it every time?

Polar's routine starts with moistening the electrode areas, so yes.

Do I rinse it?

Polar says to rinse it after every use.

Good to know

Beatcast is not a medical device. It is built for training and general wellbeing, and it cannot detect, diagnose, treat or monitor any condition. If something about your heart worries you, talk to a doctor rather than to an app.

The Bluetooth word mark is a registered trademark of Bluetooth SIG, Inc. Apple, iPhone and iPad are trademarks of Apple Inc. Polar and other names belong to their owners and are used only to say which sensors Beatcast can read. Beatcast is an independent product and is not affiliated with, endorsed by or certified by any of them.

Got yours working? Report it in r/beatcast and it goes on the list.