Heart Rate Monitor for Exercise: A Guide for Women

Disclosure: This post contains affiliate links. We may earn a commission if you purchase through our links, at no extra cost to you.

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

As an Amazon Associate we earn from qualifying purchases.

A heart rate monitor for exercise is worth buying when you want a number you can trust at higher effort, and the studies I link below checked a chest strap against a 12-lead ECG and an upper-arm sensor against a chest strap. If you only want a rough sense of effort, your watch may be enough, though both studies I link found the biggest wrist errors during walking. I’m Judy, I’m not a doctor or a trainer, and everything below comes from the makers’ own spec pages and the studies I link, not from wearing these devices myself.

If you are still choosing between a watch and a strap, start with my fitness trackers and wearables guide for women, then come back here for the strap and armband options.

Woman in a dark top walking away along a country road beside a yellow field under a blue sky — Image: Photo by Clément Proust on Pexels (Pexels License)

Table of Contents

Do I need a heart rate monitor for exercise?

You need a separate heart rate monitor only if the number itself drives a decision, such as holding a target effort during intervals or following a plan that gives you heart rate ranges. For a daily walk or an easy class, a wrist reading is a rough guide.

Comparison table of four heart rate monitors, the Polar H10, Garmin HRM-Pro Plus, Polar Verity Sense and Wahoo TRACKR, showing type, signal, battery, water rating, who each suits and one limit — Image: comparison graphic by motivationweightloss.com

One thing the studies agree on: wrist optical sensors do better in some activities than others. In a Stanford study of seven wrist-worn devices, 60 volunteers (31 women, average age 38) wore them while sitting, walking, running and cycling. Six of the seven devices had a median heart rate error below 5 percent during cycling, and the error was highest during walking, so “wrist is fine for easy exercise” is not a safe rule. The devices tested were models available when the study was published in 2017, so newer watches may behave differently (Shcherbina et al., Journal of Personalized Medicine, 2017).

Wrist or chest strap: which is more accurate for heart rate?

A chest strap or upper-arm sensor is usually the safer pick when accuracy matters, because in the 2025 study I link below, a wrist watch had a larger average error than an upper-arm sensor. In a 2025 validation study of 16 healthy adults (7 women, ages 18 to 40, all lighter skin tones (Fitzpatrick I and II)), a Polar wrist watch worn on the non-dominant wrist had an average error of 6.82 percent against a Polar H10 chest strap, while an upper-arm optical sensor was off by 1.35 percent. The authors note that the sample was small and young, and that they did not test swimming or loose wear (JMIR Cardio, 2025).

The chest strap itself has been checked too. In 25 healthy recreational adults, 11 of them women, a Polar H10 agreed closely with a 12-lead ECG for heart rate at rest, with small differences during a cycling test. The group was small and the study only looked at one kind of exercise (Polar H10 validity study, PMC). That is evidence for one strap in one setting, not a promise that every strap fits every woman the same way.

How accurate are calories burned on a heart rate monitor?

Not very. In the same Stanford study, no wrist device got its energy expenditure estimate within 20 percent of a lab measurement, and the authors advised caution about using calorie numbers in health programs (Shcherbina et al., 2017). Use heart rate to judge effort and treat the calorie figure as a loose estimate. If you are tracking food and exercise for weight loss, do not eat back the number your device shows.

What is the best heart rate monitor for exercise?

There is no single winner, because it depends on where you want to wear it and what it needs to pair with. Here is how the four I looked at compare, using only what each maker lists on its own page.

Polar H10 chest strap

The Polar H10 transmits over Bluetooth and ANT+, is rated water resistant to 30 meters (WR30), and runs on a coin cell battery that Polar says lasts up to 400 hours. Polar lists Pro Strap sizes of 62 to 82 cm in XS-S, 71 to 118 cm in M-XXL, and 91 to 155 cm in XXXL. It works with Polar’s own watches and, per Polar’s FAQ, with sports watches from other brands that accept Bluetooth or ANT+.

Who it suits: women who want a strap that has been checked against an ECG in the studies above and that pairs with many watches and apps.

One limit: Polar lists internal memory for one session of up to 30 hours, so it is not a place to store weeks of workouts, and the battery is not rechargeable.

Check the Polar H10 on Amazon

Garmin HRM-Pro Plus chest strap

Garmin says the HRM-Pro Plus sends heart rate over both ANT+ and Bluetooth Low Energy, captures running dynamics such as ground contact time, cadence and stride length, and can store heart rate during a swim and send it later. It records steps, calories and intensity minutes when your watch is off. Garmin’s manual lists a user-replaceable CR2032 battery rated up to a year at an hour a day, and 5 ATM water resistance.

Who it suits: women who already wear a Garmin watch or use a Garmin bike computer and want the extra running data and swim storage.

One limit: Garmin says the pace and distance data goes to a compatible Garmin smartwatch, so those extras do little if you use another brand.

Check the Garmin HRM-Pro Plus on Amazon

Polar Verity Sense armband

The Verity Sense is an optical sensor that Polar says you can wear on your arm or clip to swimming goggles. Polar lists up to 30 hours on a rechargeable battery, a WR50 rating, Bluetooth and ANT+, two simultaneous Bluetooth connections, and 16 MB of memory that holds up to 600 hours of training.

Who it suits: women who find a chest strap uncomfortable around the ribs and want a sensor on the upper arm. In the 2025 study above, the upper-arm placement tracked the chest strap more closely than the forearm did.

One limit: that study found agreement dropped on the forearm during high-intensity intervals, so use the upper-arm placement rather than the forearm, and remember the group was only 16 healthy young adults.

Check the Polar Verity Sense on Amazon

Wahoo TRACKR Heart Rate chest strap

Wahoo lists the TRACKR as a chest strap with a rechargeable battery rated over 100 hours, USB-C charging, Bluetooth and ANT+, up to 3 simultaneous Bluetooth connections, and an adjustable strap that fits chests up to 50 inches. An XL strap for larger chests is sold separately. Wahoo says it works with Strava, Peloton, Zwift and Apple Watch.

Who it suits: women who want a rechargeable strap for indoor cycling and class apps.

One limit: Wahoo rates it IPX7 and says it is built for wet training, not lap-pool swim tracking, and the page does not list onboard memory.

What size heart rate monitor chest strap should I choose?

Measure your chest where the strap will sit and compare it with the maker’s size chart before you order a heart rate monitor chest strap. Polar lists Pro Strap sizes by chest measurement, from 62 to 82 cm up to 91 to 155 cm. Wahoo lists one adjustable chest strap range for the TRACKR and sells an XL strap separately for chests over 50 inches. Fit matters. The authors of the 2025 study said artifacts in their chest-strap reference may have come from suboptimal fit or motion.

How long does a heart rate monitor battery last?

It depends on the type. The Polar H10 uses a coin cell battery that Polar says lasts up to 400 hours, and the Garmin HRM-Pro Plus uses a replaceable coin cell rated up to a year at an hour a day. The Polar Verity Sense and the Wahoo TRACKR both recharge, with up to 30 hours and over 100 hours listed by the makers. If you hate charging another device, a replaceable battery is the easier heart rate monitor to live with. If you would rather not buy coin cells, pick a rechargeable sensor.

Which fitness apps work with a heart rate monitor?

All four list both Bluetooth and ANT+, so the app or watch decides what you see. Wahoo names Strava, Peloton and Zwift for the TRACKR, Garmin names Garmin watches, Edge bike computers and the Tacx Training app for the HRM-Pro Plus, and Polar lists its own watches plus other brands that accept Bluetooth or ANT+ for the H10. Check that your watch or app supports the type of signal before you buy, because a heart rate monitor your app cannot read is just a strap in a drawer.

What does a heart rate monitor actually measure?

A heart rate monitor reports beats per minute from a sensor on your body, either electrodes on a chest strap or a light sensor on your arm or wrist. The data is useful for effort, not for diagnosis. It cannot tell you whether a rise in heart rate during exercise is normal for you, and that is a question for your clinician.

How do I find my maximum heart rate as a woman?

Any formula is an estimate. Tanaka et al. found 220 minus age underestimates maximum heart rate in older adults, while Gulati et al. found it overestimates peak heart rate in women. A meta-analysis plus a lab study of 514 healthy adults arrived at 208 minus 0.7 times your age, and found no difference between men and women in that sample (Tanaka et al., JACC, 2001). A separate study of 5,437 women with no symptoms, average age 52, found a lower peak of 206 minus 0.88 times your age, and concluded the male-based calculation overestimates peak heart rate for women (Gulati et al., Circulation, 2010).

For a 50-year-old, that is 173 beats per minute with the first formula and 162 with the second. An 11 beat gap is a good reason not to treat any zone number as exact.

Should I talk to my doctor before using heart rate zones?

Ask your clinician first if you have a heart condition or take medication. A zone chart cannot account for any of that, and a monitor reads your heart rate, it does not diagnose anything. Judy’s note, my experience and not medical advice: I started GLP-1 injections in May 2024 at age 47, so I would ask my own clinician before changing my exercise too.

Which wearable should I read next?

If a strap feels like too much, compare a tracker or a watch. My guides to the fitness tracker watch for women and the smartwatch for women over 40 cover those, and a strap or armband can pair with either one.

Frequently Asked Questions

Can a heart rate monitor for exercise replace my smartwatch?

Usually not. A strap or armband sends heart rate to a watch or app, and the makers above describe them that way. Garmin’s strap can log some data on its own when your watch is off, but you still need the watch or app to read the full picture.

Is a chest strap uncomfortable?

It can be, and fit varies. Polar lists Pro Strap size ranges by chest measurement and Wahoo lists an adjustable range plus a separate XL strap, so measure your chest where the strap will sit and compare it with the maker’s size chart before you order. If it still bothers you, the upper-arm Verity Sense is an alternative. One small 2025 study found its upper-arm readings tracked a chest strap closely.

Does wrist heart rate work on darker skin?

The Stanford study found device error was higher with darker skin tone, as well as in men, higher body mass index and walking, though it was one lab study with devices available when the study was published in 2017. If you want fewer surprises, a chest strap does not rely on light passing through skin, though none of the studies I link tested straps by skin tone.

Can I wear a heart rate monitor while swimming?

Check the rating first. Polar lists the H10 as WR30 and the Verity Sense as WR50 with a goggle clip, Garmin lists 5 ATM and swim storage, and Wahoo says the TRACKR is not meant for lap-pool tracking. Ratings are not a guarantee of signal underwater.

Is 220 minus my age a good max heart rate for women?

It is a rough guess. One large study of women without symptoms found it overestimates peak heart rate for women, so use your estimate as a guide and listen to your body. Ask your clinician for a tested number if zones matter for your plan.

This page is general information, not medical advice. I am not a medical professional, so talk to your prescriber or doctor before you change your exercise, especially if you take medication or have a heart or blood pressure condition.

When you decide, the Amazon links above go to search results for each device, so confirm the exact model and current price on the product page before you buy.

Sources

Heart Rate Monitor for Exercise: What Women Need to Know