Resting heart rate is a simple tool that can be really helpful in several situations. I recommend all athletes to measure their resting heart rates once in while get a picture of their normal resting heart rates. It can help you to follow your body’s reaction to training, stress and environment.

When you have a good feeling of your normal beats per minute, it’s easier for you to discover illness, dehydration or lack of recovery.

The most common way to measure resting heart rate is to put on your heart rate monitor when you wake up in the morning. Stay in bed for a few minutes and then watch your heart rate.

Should you measure resting heart rate when you sleep?

Some people actually sleep with their strap around the chest to investigate their rhytms during the night and maybe catch an even lower resting heart rate when they sleep.

Even though sleeping with the transmitter sounds more correct, measuring the whole night does not tell you much more than measuring a few minutes in the morning. For practical implications the morning routine while be just fine. Your heart rate might have been three beats lower earlier in the morning but that doesn’t matter.

Don’t make things too complicated. Measure your resting heart rate in the morning and don’t worry about your absolute lowest heart rate during the night. The morning resting heart rate works very well for practical implications. It’s not rocket science, it’s just a hint about things you probably already have a clue about.

Why is your resting heart rate higher than normal?

Illness – If you have fever, you’re heart rate accelerates with 10-15 beats for every degree your temperature goes up. When you have fever: Don’t train.

Lack of recovery – If you’ve performed a hard training session the days before, it’s very likely that your resting heart rate is 4-to 8 beats higher than normal. This is a part of the response to intensive training. It does not mean that you’ve trained too hard, but it gives you an important hint that your body need some extra recovery time before new hard training session.

Dehydration – If you’re dehydrated your total blood volume goes down and forces your heart to beat faster. Read more about central adaptations to endurance training. If you go to a hotter climate,  your body will have to acclimatize to higher temperatures and humidity. 

Why is your resting heart rate lower than normal?

Overtraining – This is not so common, but it can happen when you’ve been overtrained for a longer period.

Progress – This is probably a trend you will discover over months rather than over night. You will probably already have noticed that your resting heart is lower when you are in good shape. This is because of a larger stroke volume or more correctly a bigger parasympathic drive on the sinus node.

If you want to read more about the physiology behind resting heart rate, I suggest you read my post Central Adaptations to Cycling Training.

Polar s810 can measure your heartbeat intervals. The differences in these periods reflect your autonomic nervous system when it regulates your heartbeat. This measurement is most useful at rest or at low intensities, because we are talking about very small differences (msecs.) Your relaxation rate indicates the state of your physical recovery. If you are overtrained, it might very well be reflected on the Polar s810 monitor. 

Polar s810 agrees with clinical ECG

In a clinical perspective you will normally use an electrocardiogram (ECG) to measure the differences in length between each heart beat. This is called the R-R interval, referring to the time between two R waves in the ECG. You don’t have to understand what these waves mean, but if you have a special interest in this topic, there is an explanation here: electrocardiogram.

Heart rate monitors can protect you from overtraining

Polar s810 provides a valid measurement of the R-R intervals and calculation of the heart rate variability compared to ECG. This variability can be used as a sign of health and recovery level. I think it is interesting that a heart rate monitor can provide so precise info because it gives you the possibility to notice when you need more rest before the next training schedule. Thus, it can protect you from overtraining. In theory there should be a correlation between the state of physical recovery and your heart rate variability, and it is also concluded to be true in a couple of scientific studies.

If we take a look back at the last decades there has not been much progress in heart rate monitors: They showed the heart rate and stored some data in files (and not much compared to other digital things these days). Introducing precise details like Polar s810 is interesting and hopefully Polar watches will get competition from other products, so there will come more useful info that will make our bike training more scientific.     

Buying a heart rate monitor doesn’t have to be expensive. In fact a cheap heart rate monitor might very likely be one of your best investments in your cycling career.

If there was a performance-improving per money index, I guess a heart rate monitor would rank in the top. It is possible to buy quality heart rate monitors like the ones from Polar or Cardiosport for reasonable prices. There are also several copy products, which also have a high performance and might save you a few bucks.

Basic heart rate monitors

All companies producing heart rate monitors have some basic models made for beginners. These watches have a very limited amount of details, but are delivered at a very fair price. Measuring of heart rate is very accurate at basic heart rate monitors because they use the same techniques for measuring as more expensive models do. Basically these watches measure the current heart rate and that is it.

If all you want to know is the current amount of beats, a Polar Basic heart rate monitor could be a good choice for you. There are also some other basic models which offer a few options like target zones or average heart rate. Especially the avg. heart rate can be useful, exciting and motivating to use during training. I think that these options are an absolute minimum for a serious cyclist.

Advanced heart rate monitors

If you want to get more details and options about how your heart performs during the training session, you will have to invest in an advanced heart rate monitor. Here you will get more details about your performance and the monitor will store more data for you. E.g. how much time you have spent above you target zones.

Some of the monitors in this category can be connected to a computer so you can make graphs of your training sessions. This can be very enjoyable for some people and very useful for others. The amount of data stored on these monitors is often limited, especially when you compare with how much data you can store on an iPod or MP3 player.

For some reasons heart rate monitors have not taken part in this development. In many ways heart rate monitors are old fashioned, probably because of very few competing manufacturers. For many years Polar was the only reliable heart rate monitor on the market. Nowadays the competition is intensified, which makes the heart rate monitors both better and cheaper.

Professional heart rate monitors

If you have a scientific approach to your cycling or just want to get all details registered, you have to buy one of the professional heart rate monitors. These watches store huge amounts of data. Actually they can store every single beat from your heart. This makes it possible for you or your coach to make some very comprehensive analysis of your training on your personal computer. To get the full value out of a professional heart rate monitor like Polar s810, you need to have some interest in exercise physiology.

Resting heart rate is not always equal to performance

Monitoring your resting heart rate is a good discipline to integrate in your daily procedures since it can give you some important information about your fitness. When you have registered your resting heart rate in the morning for a period of time (months) you will start to see a pattern.

There are days with low resting heart rates and there are days with high values.

Notice long term changes in resting heart rate

The most important observation for you will be that there is some but not a total correlation between resting heart rate and cycling performance.

Small differences in the same week has nothing to do with improved performance but is a lot more a question about level of recovery, sleep pattern, physical and psychological stress level etc. Differences observed over a longer period (months) might very likely be seen because of a central adaptation. Due to a better relaxation (regulated by autonomic nerve system) there is a better filling of the heart in the diastole and thus a larger stroke volume in the systole.

Don’t compare heart rate values…
As I have mentioned a couple of times before: It doesn’t make sense to compare absolute heart rate values with others because we all have a different anatomy. As an example, I have registered a low resting heart rate of 36bpm in a period with a very small amount of cardiovascular training.

I wonder how many of you hard training individuals who have the same value? That doesn’t matter! You are probably stronger than I was at that time anyway…

As you can see from the many comments (currently more than 136 comments) to my article ‘What is Your Lowest Heart Rate ever?‘ there are many people around in the world with low resting heart rates. Many of the comments illustrate that resting heart rate in it self is a good but not really good predictor of performance.

Question from Rob Worrell: “My seasonal goal was an 11mile hill climb near my home at the conclusion of the summer. In interval training I once hit 182BPM (I am 39 Years old), but most of my intervals are around 160-170BPM. In the MTB hill climb race (seasonal goal), I averaged 173BPM for a 1:05:30 race time. This seems like my threshold is really close to my max of 182BPM? I lost by 6 minutes or 33 seconds per mile. Do I need to increase my threshold even higher? Or how do I get more power at the same threshold?”

Threshold heart rate and threshold watts are two different terms. Your best average heart rate for a one hour event is probably very close to your performance in the MTB hill climb race you mention. This means that on that specific day, you delivered an optimal performance.

No training = Lower threshold power

If you didn’t train the last 12 weeks before this event, you would probably still be able to maintain an average heart rate close to 173bpm, but there is no doubt that your finishing time will be significantly slower. This is because your threshold watts at the same heart rate are much lower when you haven’t trained.

More training = Higher threshold power

Thus, when you train consistently and do some good workouts, your threshold power output will increase, but your threshold heart will very likely remain at the same level. You are close to the limit of how much you can push your average heart rate, but that is in fact uninteresting. There is a huge aerobic potential waiting for you, when you start to work focused on your threshold power. In theory, there is no limitation on how far you can raise you power output.

The main training methods for threshold power are VO2 max intervals, aerobic intervals and endurance rides.