Archive for the 'Heart Rate Training' Category

Polar Heart Rate Training Plan Bank

Monday, December 17th, 2007

Within the Polar Training Plan Bank you can find training plans for various endurance sports created by top coaches.

You can save these plans to your own Polar ProTrainer 5″ training calendar which will allow you to transfer each training session to your Polar RS800, RS400, CS600 or CS400 to guide you through each training session. You can then transfer your complete training files back to your ProTrainer 5″ training calendar and compare your actual results with your targets.

You will find examples of various types of training plans. There are plans for various levels and for a qrange of different events. Each plan has a short description that will allow you to get an overview. We will regularly add more training plans, helping you to get even more out of your training.

Feel free to share these training plans at web sites and to runner’s forums. You can also e-mail the plans to your friends and club mates.

If you are coaching and have good plans, the ProTrainer 5″ allows you create and share your own plans as well. To go to the Polar Training Plan Bank, click here.

How to Utilize Polar Running Index in Your Training

Thursday, August 23rd, 2007

I don’t often interject my own musings because most of you know by now that I have used a Polar heart rate monitor for over 20 years. Each model that I have used has been great in its own way and so it is with the RS800sd that is now my constant companion. At 56 and having run for 40 years, I won’t be setting any PR’s or breaking any records, but my RS800sd does give me some feedback that I will always cherish. That feedback is my running index, which averages about 65 and has been as high as 70 and what that tells me is that even though I am not fast, I am very efficient at running and that is perhaps one of the biggest reasons that I still love to run so much. In the following article, you will learn how using the Polar running index feature found on the RS400sd and RS800sd can guide you in your training, too.

Running Index offers an easy way to monitor performance changes. Performance (how fast/easily you run at a given pace) is directly influenced by aerobic fitness (VO 2max) and exercise economy (how efficient your body is at running), and Running Index is a measurement of this influence. By recording your Running Index over time, you can monitor progress. Improvement means that running at a given pace requires less of an effort, or that your pace is faster at a given level of exertion. The Running Index feature calculates such improvements. Running Index also gives you daily information on your running performance level which may vary from day to day. Continued…

Simple reasons to use a Polar heart rate monitor

Tuesday, August 14th, 2007

Effective training and exercise means knowing how often and how hard to train. In its most basic form, a heart rate monitor is like a rev counter for your body, giving you a precise measurement of your exercise intensity. Different intensities bring different benefits, and following a well balanced plan will result in greater improvements in a shorter time. Simply put, whether you are planning to compete in a world championship event or are just looking to maintain a basic level of health and fitness, the unique and personal information a heart rate monitor provides will help you get the most from your efforts, remain on track, and stay motivated.

The principles of heart rate-based training may not have changed since 1982 when Polar introduced the very first wireless heart rate monitor, but the technology has evolved in leaps and bounds. Measuring more than beats per minute, Polar products can now sense changes in the autonomic regulation of your heart beat (such as changes caused by a lack of sleep, post-training fatigue, jet lag, illness, etc) and will automatically guide you to exercise at the optimum intensity for your current physical condition.

Polar takes the complexities of exercise physiology and creates simple features that make safe and effective training possible for everyone. For coaches and serious athletes, complete training solutions incorporate heart rate and recovery, performance, technique and environmental measurements (e.g. speed, distance, cadence, power, altitude etc.) along with PC software to provide the precise planning and analysis needed to achieve top performance.

Polar OwnZone Training

Friday, January 5th, 2007

We are all familiar with daily changes in our mental and physical condition. On one day, we may be full of energy - on the next feel completely drained. The human body is not a machine, and still great demands are put upon it. It must react to constant changes and quickly adapt to new situations.

It is particularly important to listen to the signals of the body during physical exercise. One key signal of the body is the heart rate – the only variable that can be continuously measured to evaluate your training intensity. Therefore, the basis for the determination of the OwnZone is your actual individual heartbeat. Continued…

How to Use the Polar OwnCal Feature in Your Weight Loss Program

Friday, December 1st, 2006

In Polar heart rate monitors with the OwnCal Feature, exercise duration can be determined by using your desired calorie expenditure as your goal. Daily and weekly exercise goals can conveniently and easily be set in terms of calories burned. Because the heart rate monitor tracks both the energy/kcal expenditure in one exercise session and the accumulated kilocalories of several sessions, during, for example, a week or a month, it helps in achieving the energy expenditure goals.  For more information on using Polar heart rate monitors for healthy weight loss, click here.

Factors affecting exercise energy expenditure
The amount of energy expended during exercise depends on exercise intensity and duration. The higher the intensity and the longer the duration, the greater the energy expenditure. Energy expenditure is also dependent on body weight, so that a heavier person consumes more energy than a lighter one when performing the same exercise because the mass that the person needs to move is greater. For example, persons weighing 130 pounds and 260 pounds expend 5 kilocalories and 8 kilocalories per minute in brisk walking, respectively. Also, the larger the muscle mass used in the exercise the greater the energy expended. Thus, very high energy expenditures can be reached in exercise that involves cross-country skiing and rowing, for example. Types of exercise where the person must support his/her body weight typically expend more calories than types where the exercise equipment supports the weight.

Physical activity for weight loss purposes
For weight loss purposes the recommended energy expenditure can be set to 300 kcal/ session. Conducted on most days of the week this will result in a calorie expenditure of 2000 kcal/week on a 155 pounds person, approximately the kilocalorie content of 2 pounds of fat in a month.

Comparison between the distribution of energy sources in jogging and walking

Comparison between the distribution of energy sources in jogging and walking

Why You Might Be Getting Abnormal Heart Rate Readings When Exercising

Thursday, November 30th, 2006

There can be several reasons for abnormal or irregular readings during exercise. Due to the same reasons, heart rate may stay at the same value for a long time or the heart rate stays at zero (0).

1. Poor contact between the skin and the electrodes of the transmitter

For accurate heart rate measurement, the contact between skin and the electrodes should be as good as possible. Polar transmitters measure the ECG signal from the chest, where it is the strongest. The weak heart-generated signals need to be accurately measured before the calculation of the heart rate. It is therefore important to ensure that the contact between the skin and the electrodes is as good as possible. Here are some tips how to ensure good contact:

  • 1.1. Moisten the grooved electrode areas on the back of the transmitter. At the beginning of the exercise session your skin may be dry and the moisture will help ensure better contact. When you start to sweat the contact will improve because the salt in the sweat conducts the electrical signals very well. Saliva is a good conductor as well.1.2. Tighten the elastic strap of the transmitter. If the transmitter is loose, the movement of the electrodes disturbs the detection of the ECG signal. If the standard strap does not fit satisfactorily, larger and smaller elastic straps are available as accessories.

    1.3. The type of the ECG signal slightly varies from person to person. The form of the ECG signal can depend on form of the chest, the anatomical location and position of the heart, position of the electrodes and the amount of body fat. If the ECG signal is weak, disturbances can more easily spoil the signal. Find the best contact by turning the transmitter left or right, or place it lower or higher. There have been cases where the transmitter detects the heart rate better when it is turned upside down so that the Polar logo is upside down and facing out, or even when attached on the persons back with the Polar logo upside down and facing out.

    1.4. For active sports like aerobics or marathons, women can use the accessory Heart Bra which makes the transmitter stay in place better. Ask your local Polar dealer or distributor for the availability of this product.

    1.5. Hairy chest may also weaken the contact. Try to find the best possible position for transmitter.

    1.6. In demanding cases, use conductive electrode lotion or gel to improve the contact. After using them, it is very important to wash the transmitter carefully.

2. Wear and tear of the transmitter

Proper care of the transmitter after use ensures longer service life for the transmitter.

  • 2.1. Wash the transmitter regularly after use with a mild soap and water solution. Dry it carefully with a soft towel after washing.
    Never store the transmitter when it is wet. Sweat and moisture can keep the electrodes wet and the transmitter activated, which shortens the battery life.2.2. Store your Polar heart rate monitor in a cool and dry place. Make sure that the electrodes do not contact anything damp, such as sport towel or wet elastic strap. Do not store a wet transmitter in any kind of non-breathing material, such as a plastic bag or a sports bag.

    2.3. Do not bend or stretch the transmitter. This may damage the electrodes.

    2.4. Only dry the transmitter with a towel. Hard-handed handling may damage the electrodes.

    2.5. Keep your Polar heart rate monitor out of extreme cold and heat. The operating temperature is -10 ºC to 50 ºC/ 14 ºF to 122 ºF. Do not expose the Polar heart rate monitor to direct sunlight for extended periods, such as leaving it in a car.

    2.6. The transmitter can be washed with mild soap and a gentle brush. If the electrodes appear discoloured, the transmitter needs to be washed. Do not use any alcohol or a solvent based detergent.

3. Electromagnetic disturbances

Electromagnetic disturbances may occur near high voltage power lines, traffic lights, the overhead lines of electric railways, electric bus lines or tram lines, televisions, car motors, bike computers, some motor driven exercise equipment, cellular phones or when you walk through electric security gates. Check your surroundings and move away from the source of interference, or remove the source of the disturbance.

4. The distance between the transmitter and the receiver is too great

The maximum transmission range between the transmitter and the receiver is 1 metre (3 ft). If the distance is greater, the receiver may not get all the signals sent from the transmitter. In cases where the transmission range is at it is extremes, for example rowing or biking where the receiver is not attached to the wrist, the receiver may display the same heart rate for a long time. To avoid this, keep the distance within 1 metre.

5. Signals from more than one Polar Transmitter within 1 metre transmission range
Note only with non-coded transmitter (T31)!

In cases where are more than one transmitter nearer than 1 meter, and you are using the non-coded transmitter, your receiver can pick up the signal from all transmitters within the range, this can result abnormal high readings. Even if the other transmitter is coded, and yours is non-coded, your receiver may still give an inaccurate reading. To avoid signal crosstalk, keep the distance to the other transmitters.

The coded transmitter and receiver system does not pick up the signal from other heart rate monitors. In case of false readings with a coded transmitter and receiver, check if the code has been locked. After a successful code search, a frame will appear around the heart symbol on the display. If the frames around the heart cannot be seen start the measurement again and check that you are not near other heart rate monitor users, because they may interfere the code search. Also, high voltage power lines, televisions, mobile phones and other sources of electromagnetic disturbance may interfere with the code search, as well as keeping the receiver too close to the transmitter.

6. Static electricity, technical sportswear and special conditions

If the humidity of the air is low, or you are exercising in windy conditions (for example high-speed road racing), a fluttering shirt may rub the transmitter and generate static electricity. This causes additional signals, especially if the contact between skin and transmitter is poor. To avoid this:

  • 6.1. Moisten the electrodes before use, or use the conductive lotion or gel
    6.2. Use a cotton shirt instead of a synthetic shirt
    6.3. Use a tighter shirt to avoid fluttering of the material
    6.4. Use the transmitter on a wet shirt
    6.5. Wet the shirt

7. Arrhythmia

Polar Heart Rate Monitors are not designed to detect arrhythmia or irregular rhythms and will interpret them as noise or interference. The computer in the wrist receiver will make error corrections, so that arrhythmia beats are not included in the averaged beats per minute. The blinking heart symbol in the face of the wrist receiver, however, will continue to show all heart beats received. In most cases the Polar Heart Rate Monitors will work fine for persons with arrhythmia.

8. Battery of the transmitter is getting empty

The estimated average battery life of the Polar Transmitter is 2500 hours of use. If the battery of the transmitter is running low, the transmission range decreases and may cause errors similar to the ones listed above in this document.

Why Polar Chose the S1 Foot Pod Technology Instead of GPS

Thursday, November 30th, 2006

Q: Why didn’t Polar use GPS technology for speed and distance for the S625X Running Computer and the new RS400sd?
We considered both GPS and inertial technologies carefully before choosing to go with inertial technologies. GPS has some positive elements but we chose the best overall technology for running anywhere and in any conditions. We recognized that existing GPS was too heavy and consumed too much power for an application that was meant for runners who are demanding and relatively heavy users and train frequently. Existing GPS applications are simply not as practical for someone who is running frequently because of the need to constantly recharge/replace batteries and because of the discomfort of hauling abound a large GPS unit on the upper body. When used in a real life running scenario- GPS is no more accurate that inertial sensor technology. With inertial technology we saw that we could provide the best solution for runners who want accurate and reliable speed and distance measurement that performs in all conditions (indoors and outside), in urban city settings with tall buildings, even in very heavily wooded trails and twisting turning trails and tight turning paths.
Q: GPS technology is considered advanced by many. What about the Polar inertial sensor technology that Polar uses?
The inertial technology that Polar uses is very advanced, inertial technology is used in aerospace positioning and guidance systems, industrial robotics and in advanced automotive applications such as active suspensions and emergency airbag deployment to name a few. The inertial sensors measure the acceleration of the S1 foot pod more than 1000 times per second and use this data with advanced algorithms to calculate foot angles and gait velocity the Polar S1 running speed and distance sensor is NOT A PEDOMETER. Instead, it is very advanced running speed sensor.
Q: GPS provides speed and distance while running, cycling and even during X-C skiing. What about the Polar S625X?
The Polar S625X was designed primarily for runners and tri-athletes. So we have ensured that the running functions are optimized for running and cycling. The S625X is fully compatible with all Polar cycling sensors. Combining cycling speed and cadence and power options provides many more dimensions to the cycling cross-sports experience than that offered by GPS speed and distance unit.
Q: Some GPS units provide directional features to help navigation. Why has Polar opted to leave this out in the S625X? The S625X was designed with the knowledge that 80% of runners generally run the same 3-5 routes. The speed and distance element of the S625X will support people who want to track speed and distance on these routes and also lets them find more new routes with no need for external mile markers. Navigation features are best suited for outdoor and adventure products, while the S625X is focused on providing runners the most relevant features for building performance and enhancing their every running experience.
Q: Is the S1 footpod heavy? You can’t feel it when once its attached to your shoe. Infact, you will struggle to figure out (by feel) which shoe has the footpod on it once you put it on. The Polar S1 footpod is built to last with robust water resistance, shock resistance and easy battery change while still not reducing shoe comfort or running performance.
Q: How accurate is the S625X? Generally the S625X is at minimum 97% accurate even without calibration. The accuracy increases to 99% with calibration. In relative terms, this accuracy is as good or better than the accuracy provided by GPS. Interestingly, this degree of accuracy is generally far better than what is seen on running treadmills. Have you ever heard of a runner complain that a treadmill was not accurate enough for their training purposes?
Q: Do I need to re-calibrate my footpod everytime my foot pod or wrist unit battery is changed? If you choose to calibrate your Polar S1 foot pod, the calibration factor will be stored in the permanent memory of the S625X Running Computer. This calibration will be stored permanently, unless you decide to change it….so if you calibrate, you only need to do it once.
Q: Will the Polar S1 foot pod leak water? Robust water-resistance and durability are key elements in the design of the Polar S1 foot-pod. It will survive immersion, wet running environments and continue to perform reliably. However, the S1 was not designed for swimming or aqua-running so please do not going swimming with it.
Q: What is the foot pod battery lifetime? The battery lifetime is 20 hours of use in average.
Q: How do I know that the foot pod battery needs to be replaced? When the green light on the foot pod turns red, you need to replace the battery. Replace the battery in case the foot pod does not start or the running speed shows 00 constantly.
Q: Can I replace the battery myself and if so, what is the battery type? The foot pod is designed so that the user can replace the battery him/herself without tools.The battery type is AAA. You can learn more about Polar running heart rate monitors with the S1 Foot Pod at - - as well as the Polar RS800sd with the S3 Foot Pod by going to

Running with your Polar heart rate monitor

Thursday, August 17th, 2006

The first step to integrating your heart rate monitor into your running program is to determine your individual training zones. These are the zones that you will use for Recovery/Endurance, (60-70%), Aerobic (70-80%) and Anaerobic (80%+) training. Some trainers advocate as many as five training zones, and that may be right for your training. These are the core zones that we use to demonstrate how a program would work. . Once you establish your zones, your heart rate monitor will allow you to meet the training goal for each day’s workout.

So how do you find your zones? The key is to establish personalized numbers that work for you. When using a formula, which is recommended for weight conscious or fitness runners, you establish your zones off of estimated max heart rate. We recommend the Karvonen formula that factors in your Morning Resting Heart Rate (MRHR). This will personalize numbers not only for your age, but also for your fitness level. Just follow the instructions listed below.

For the more serious or competitive runner, knowing your Anaerobic Threshold (AT) is the key to your training. This is the point where your body goes from Aerobic, to Anaerobic and lactic acid starts to become a factor. By knowing this point (on average between 80 and 90% of Max hr), you can fine-tune your zones. The most effective way to determine your AT is having it determined in a clinical environment. These tests are more common today and can be done at a sports training facility or clinic. As an alternate, you can take a sub-max test like the one recommended by Carmichael Training Systems (CTS) These tests, while not as efficient as having it done clinically, can give you a more precise foundation for establishing your training zones than a formula.

Karvonen Formula

First, you must take your heart rate for three mornings in a row before getting up from bed. Once you have those numbers, take the average of the sum:

Morning 1# + Morning 2# + Morning 3# = ( X)
(X) Divided by 3 = Morning Resting HR (MRHR)

This is the single best indicator of your state of fitness. Once you have this number established as a baseline, you could use it to understand more about yourself than you can imagine. Take it again every once in a while, at least once every two weeks.

As your fitness improves, you will most likely see that number going down.

If you see an elevated number, it could mean the following:

  • You did not recover from a hard workout the day before
  • You need more rest
  • Your body has begun fighting off an oncoming illness

This is critical information, especially on days when you have a hard workout planned. You may have to adjust your expectations for that workout, or put it off for the next day when you are better rested.


Target Zones

The next step is to set up your target zones. Some experts advocate as many as 5 Target Zones. For the sake of simplicity, we will talk about the three key zones:

60-70% Builds endurance, recommended for recovery
70-80% Good for tempo workouts
80+ Interval workouts and AT training

First use the formula:

220 minus your age (A)= estimated max hr (HRMx)

HRMx minus MRHR= (C)

Now find your personal target zones

(C) X .60 = (D) D + MRHR = ( ) 60% limit number
(C) X .70 = (E) E + MRHR = ( ) 70% limit number

Jeff is 40 years old and his morning resting hr is 38.

220 minus 40 = 180
180 minus 38 = 142

142 X .60 = 85  85 + 38 = (123)
142 X .70 = 99  99 + 38 = (137)

For Jeff’s Long Workouts his target zone is 123-137

Now use that formula to find all three of your target zones. You may have to use this as a starting point and adjust your numbers after several workouts. If you’re serious, visit a sports clinic and get your AT tested.

The Polar S-Series Products have the patented OwnIndexS feature. You can test your Vo2max and actually get a rating of how well your body processes oxygen. This will allow you to track improvements and even see if you are genetically predisposed to be a world-class runner.

Using a Polar heart rate monitor for weight loss and weight management

Tuesday, August 15th, 2006

Let’s get started!

Step 1
Determine Your Personal Target Zones

Target Zones

60-70% of max hr weight loss, building endurance
70-80% ” ” “ weight management, improve cardio fitness

Now use one of the following formulas to set up your TZs

Option 1 Age-based formula
220 minus your age (A) = estimated max hr (HRMx)

    To find your target zones

    MHR X .60=( ) MHR X .70=( ) TZ1
    MHR X .70=( ) MHR X .80=( ) TZ2

    You now have your two personal target zones

Option 2 Karvonen formula
This formula uses your age and fitness level to determine your target zones. It’s a more personalized number.

First, you must take your heart rate for three mornings in a row before getting up from bed. Once you have those numbers, take the average of the sum:

Morning 1# + Morning 2# + Morning 3# = ( X)
(X) divided by 3 = Morning Resting HR (MRHR)

This is the single best indicator of your state of fitness. Once you have this number established as a baseline, you can use it to understand more about yourself than you can imagine. Take it again every once in a while, at least once every two weeks.

As your fitness improves, you will most likely see that number going down. And that’s important. It takes time to start losing the weight. Many people quit because they get on the scale and they don’t see any difference. This number will tell you that your fitness level is improving. That means the weight should be coming off soon after. By seeing that you’re actually improving, you’re more likely to stick with it.


Now use your resting heart rate number as follows:

220 minus your age (A)= estimated max hr (HRMx)

HRMx minus MRHR= (C)

Now find your personal target zones

(C) X .60 = (D) D + MRHR = ( ) 60% limit number
(C) X .70 = (E) E + MRHR = ( ) 70% limit number

(C) X .70 = (D) D + MRHR = ( ) 70% limit number
(C) X .80 = (E) E + MRHR = ( ) 80% limit number

Janet is 40 years old and her morning resting hr is 58.

220 minus 40 = 180
180 minus 58 = 122

122 X .60 = 73.2 73 + 58 = 131
122 X .70 = 85.4 85 + 58 = 143

Her 60-70% Target Zone would be 131-143

Now use that formula to determine both of your target zones.

Option 3 OwnZone™ Feature
If you own one of the M-Series models, just follow the instructions on how to go through a warm-up and it will find it for you automatically. Once you have it, start your exercise. If you ar looking for a lower intensity workout, stay in the lower half of the zone. If you seek higher intensity, keep it in the upper half. It’s that easy.

Option 4 Stress test
Have your physician perform a stress test and determine your max hr and
target zones for you. This is especially important if you are just starting out
an exercise program, are obese, or are coming back from a long layoff.

Step 2
Choose the Zone that corresponds to your goal

If you’re exercising to lose weight, try to do at least three workouts a week for 30 minutes in your 60-70% target zone. Time and intensity are the keys. If you can go longer, you will only benefit more.

Exercise Tip: You can burn almost twice as many calories by exercising twice a week for 1 hour, as you would exercising 5 times for 30 minutes. (Pocket Personal Trainer by Eric Harr)

As you get more fit aerobically, you should try different workouts each day. Your body will adapt to your exercise if you do the same thing over and over. Now that you have an HRM and know your Target Zones, you can use any activity to get a workout. Just let your HRM guide you.

Sample workout week once you move beyond a beginner:

Monday Exercise for 45 minutes to 1 hour at 60-70 %. Take the first 10 minutes to warm up below 60%.

Wednesday Walk to hill near your house below 60% as a warm-up. Once there, do hill repeats (walk up and recover while walking down, then repeat). While walking up, don’t let your heart rate get above 80%. When walking down, don’t start the next hill climb until your heart rate gets back down to 60%. Start with three of these and add on from there. Walk home at 60% to cool down

Friday Warm up for 10 minutes at 60%. Then exercise for 15 minutes at a steady pace staying in the 70-80% range. Then cool down for 5 minutes at 60% to cool down.

Weekend Try another activity using your HRM.

There are many different heart rate-based exercise programs available on the Internet or in books. Try the sample workouts above, or find one that works for you.

The key here is calorie burning. You need to exercise long enough to maximize calorie burn. But if you are like most people, you also have time constraints. An hour workout is a great benchmark to work towards, because you can get great caloric burn during 60 minutes. Variety is the key. A good rule of thumb. If you have the time, do a longer workout at a lower intensity (60-70%). If you have 30 minutes, warm-up and try to maintain a higher intesity (70-80%). You want to maximize the time that you have. If you have no time constraint, then build a program that incorporates both, like the one listed above. Make sure you are ready to take on those types of workouts. Check with your doctor before you move to the next level of exercise.

Some tips for using your Polar transmitter belt

Monday, August 14th, 2006

If you are having difficulty with the transmitter it may be due to one of the following reasons:

Electrical Interference:   Erratic readings on the receiver are usually caused by interference.  If the heart rate readings appear to be abnormal, check that your Polar HRM is not within range of other strong electromagnetic signals.  Common sources are televisions, computers, cars, cellphones,TV antennas, high voltage power lines (both above and below ground) and some exercise equipment.  Re-locating the position of the wrist receiver can usually solve this problem.

To find a location that has no interference, remove the chest transmitter and exercise as usual.  If the heart symbol continues to flash, you are picking up interference. In this case, move the wrist receiver to a location where it does not flash, then replace your chest transmitter.  In most cases when the interference is cause by a piece of exercise equipment, placing the wrist receiver on the side rail, away from the front electronics display of the equipment will correct the problem.

Please note:  Static electricity in clothing or a flapping shirt can cause electrical interference, so some items of clothing, i.e. man-made fibers, could be the cause.   Please try wetting the t’shirt in the area where the transmitter is.

Poor Conductivity: It is important that the electrodes are wet during the heart rate measurement mode.  If water does not ensure the flawless transmission, you can use water-soluble conductive cream instead.  If you choose to use a conductive cream, apply it to the ribbed-area of the transmitter belt only.

Dirty Electrodes: The transmitter electrodes should be cleaned with a mild soap and water solution and thoroughly dried after each use. Try cleaning the electrodes and test the transmitter again.

Positioning:  If the electrodes are clean and moist, and there is still no heart rate registering on the receiver, try to shift the transmitter around to the side of your body (try the left side first) or position it lower or higher on the chest.  In some cases, you can try the transmitter on your back, however, the belt must then be worn with the Polar logo upside down and facing out.  This ensures that the left electrode stays on the left side of the body and the right electrode stays on the right side of the body.  Make sure to wet the electrodes every time it is moved to a new position.

Medical Condition: There are a very small number of cases where a Polar HRM will not work due to a medical condition, for example: low voltage R-wave signals; atrial fibrillation or bundle branch blocks.