Heart rate monitor

One of the secrets to optimal fitness isn't just the amount of exercise you get. It's the intensity level of that exercise—not too high, not too low. A heart rate monitor (HRM) is a useful tool to find this "sweet spot" of heartbeats per minute.

What's the best heart rate monitor for you? This article will help you narrow your search.

Shop REI's selection of heart-rate monitors.

Who Can Benefit from a Heart Rate Monitor?

Use a heart rate monitor to follow your cardiovascular ups and downs during recreational or competitive activity. All but the most basic models are designed to help you stay in your optimal heart rate target zone (described in more detail below) through your entire workout. Many models let you further analyze data via your computer.

Caution: Before initiating any exercise program, consult a physician to design a program that is well suited for your goals and current conditioning.

Typical users:

Joggers and walkers: Recreational exercisers can benefit from heart rate monitors in the same way as elite athletes do. By aiming for fat burning and aerobic target zones on your HRM, you can get more out of your exercise time.

Runners: A heart rate monitor can keep you in your peak target zone on intense training days and at your aerobic base during easier sessions. Some can alert you when you're dehydrating or are reaching a nutritional deficit.

Cyclists: An HRM can track your training performance during endurance, tempo and interval rides, whether you bike a road, trail or stationary trainer. Some models deliver more feedback via a cadence sensor or foot pod.

Hikers, climbers and skiers: On the way up, use a heart rate monitor to condition more effectively for a peak ascent. On the ride down, skiers can track their thrills while carving through powder.

Weight-loss participants: HRMs help with regular exercise and a sustainable dietary regimen. Most display calories burned during a workout; many can help target your exercise for maximum fat burning.

Injury-rehabilitation patients: Real-time feedback makes HRMs valuable for physicians and their patients recovering from an injury or an illness, including a cardiac incident. Such data can help ensure that your gradual return to full strength and endurance proceeds safely and steadily.

Types of Heart Rate Monitors

Heart rate monitor

All heart rate monitors work by measuring electrical signals from the heart and displaying them on the unit's data center. Leading brands include Garmin, Polar, Suunto and Timex

There are 2 main types of heart rate monitors:

Chest Strap Models

By far the most common style, these consist of a chest strap that fastens around the chest and wirelessly transmits continuous heart rate data to a wristwatch-style receiver.

Model features vary widely:

  • Basic models: These time your workout and give you continuous, average, high and low heart rate data.
  • Advanced models: Many of these submit a coded signal to prevent other HRMs from interfering with your data. They can be partnered with a foot pod (described in the Speed and Distance features below) that attaches to your shoelaces to track your speed, distance and cadence. Some have GPS receiver capabilities to help you mark/find locations, give elevation and save previous course info.

HRM chest strap, USB stick and foot pod

Pros: Chest-strap models offer continuous heart rate information without needing to stop during exercise to measure or view it. Accuracy tends to be better than with finger sensor models, and they offer more options, such as speed and distance monitoring via GPS receivers.

Cons: These are usually more expensive than finger sensor models. Low-end chest-strap models don't prevent crosstalk (interference) with other wireless heart rate monitors. Some chest straps are less comfortable than others.

Finger Sensor Models

These consist only of a wristwatch-style monitor. Simply touch a finger to the unit's touch-pad sensor to activate the heart rate monitor. Finger sensor data is estimated to be 95% accurate.

Pros: No chest strap means greater simplicity and comfort. Finger sensor models are more affordable than most chest-strap models.

Cons: You must pause during exercise in order to take a measurement. They tend not to be as accurate as chest-strap models. There is no option for integrated speed and distance monitoring.

Shop REI's selection of heart rate monitors.

Understanding Heart Rate Target Zones

A key benefit of a heart rate monitor is that it helps you maintain the optimal heart rate target zone for your specific goal. In effect, the HRM is your pacer, telling you when to speed up or slow down. Higher-end models inform you of this via a digital display and/or an audible tone.

Exercising in the right heart rate zone helps optimize your performance. A fat-burning goal may require 40 to 80 minutes in one zone, for example, while an aerobic conditioning workout might mean 10 to 40 minutes in another.

The target zone is a percentage range based on your maximum heart rate (HRmax). Various algorithms have been developed to calculate an HRmax estimate, but the simplest is:

HRmax = 220 – your age.

The American Heart Association offers the chart below as a general guideline. (Note that some medications can affect your target rate zone.) However, it is always best to have a stress test under a physician's supervision to determine your actual HRmax.

  Heart Rate Target Zone
Avg. Maximum Heart Rate
Beats/minute Beats/minute
20 100–170 200
25 98–166 195
30 95–162 190
35 93–157 185
40 90–153 180
45 88–149 175
50 85–145 170
55 83–140 165
60 80–136 160
65 78–132 155
70 75–128 150

A maximum heart rate at different aerobic zones provides specific results:

  • Endurance (60%–70%): Considered ideal for endurance and weight-loss programs. Develops cardiovascular and muscular efficiency. The body learns to use stored fat as fuel.
  • Aerobic (70%–80%): Ideal for overall cardiovascular fitness, muscle strength and weight management. The body burns mostly fat and carbohydrates in this zone.
  • Anaerobic (80%–90%): Used for interval workouts or consistent speed. At this zone, your breathing will be heavy and your muscles tired. Enhances lung capacity and increases lactate tolerance.
  • VO2 Max (90%–100%): Helps enhance speed in athletes (who exercise at this level only for short periods as muscles quickly go into oxygen debt).

Compare Heart Rate Monitor Features

An HRM's wristwatch-style receiver gives you real-time data on your workout's efficiency. Most models provide average heart rate, as well as the high, low and target heart rate reached during your workout.

Basic models offer up to 3 target zones; advanced models have from 3 to 6 target zones. With the capacity for multiple target zones, you can preprogram your heart rate monitor for a series of different workouts (e.g., endurance, aerobic and anaerobic variations described above). If your HRM offers only a single aerobic target zone, you'll need to reprogram it every time you want to change the exercise parameters.

Other features to consider when shopping:

Sport watch: Includes features such as a countdown timer, calendar and clock.

Stopwatch and lap/split times: After each lap at a track or every mile on a marked-distance race course, hit the "Lap" button to see how your pace has changed throughout your workout or race (a.k.a. your "split").

Recovery heart rate mode: Tracks the time it takes your heart to return to its normal, resting rate. It's a good indicator of cardiovascular fitness and especially important if your workouts include sprints or interval training.

Time in target zone: Tracks the time you spend exercising within your target zone. Some zones and goals require more time than others.

Calorie counter: Estimates the calories burned during exercise. This can be especially handy if your workouts are part of a weight-loss program.

Foot pod

Speed and distance monitor: Calculates the speed and measures the distance covered in a particular workout. This is typically done via a GPS receiver for outdoor use or a foot pod for indoor use or use in an outdoor area with limited satellite reception. A foot pod uses an accelerometer to determine the length of each stride. For details, see the REI Expert Advice article, Speed and Distance Monitors.

PC interface: Connects your heart rate monitor to your home computer so you can download training statistics for analysis and storage. This may be wireless or require a separate computer connection.

Fitness trainer: This provides alerts for intensity levels that fall above or below your chosen training zones.

Coded transmitter: Encrypts transmissions from the chest strap to the wristwatch-style receiver to prevent crosstalk, which are signals from the wireless HRMs of others exercising around you.

Bicycle-mounting options: Many HRMs can dock to a bicycle's handlebar, though doing so may require a mounting accessory. Add a speed and cadence sensor to your bike to help maintain your cycling rhythm.

Battery replacement: Many, but not all, HRM wrist receivers use consumer-replaceable batteries to simplify maintenance.

Heart Rate Monitor FAQs

Q: How does heart rate relate to fitness?

A: Blood carries oxygen to your muscles, which need that oxygen in order to perform. An efficiently beating heart delivers oxygen to the blood more effectively than an unhealthy heart. As a result, oxygen consumption is closely related to heart rate, particularly when exercise intensity increases.

Q: Why do I have a different maximum heart rate for different sports?

A: You use distinct muscles groups for varying lengths of time at different intensities. Your maximum heart rate will generally be higher when employing more muscles for shorter periods with more force. A sprinter might have a higher heart rate following a 400-meter race, for instance, than a distance runner after a 2-mile race.

Q: How does a heart rate monitor work?

A: Either a wireless chest strap or a finger-activated pulse monitor on your wrist detects your pulse electronically and sends that data to a wristwatch-style receiver, which displays your heart rate.

Q: Will a foot pod work with any heart rate monitor?

A: A particular brand of foot pod will generally work only with the same brand of heart rate monitor.

Q: How does a foot pod work?

A: A foot pod is an alternate means (as opposed to a GPS unit) of calculating speed and distance. It uses an accelerometer to estimate the length of each stride, taking into account variations due to terrain, fatigue, etc. Some HRMs combine your foot pod's stride data with other calibrating information to approximate your speed and distance. These generally display your current pace, though many cannot save data for later analysis. A heart rate monitor with a properly calibrated foot pod can provide distance measurements with accuracy similar to GPS receivers, and even better in locations where GPS reception is poor, such as indoor tracks.

Q: Will a GPS heart rate monitor work when I'm trail running?

A: GPS receivers can track your speed and distance wherever satellite signals are present. Unlike a foot pod, it can also help map your course. Problematic areas are those where signals cannot penetrate, such as forests with dense canopy vegetation or canyons. If you are unsure about a training location, try running it with your GPS heart rate monitor. If the GPS receiver cannot hold the signals, buy a compatible foot pod later.

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