Why And How To Find Heart Rate Threshold For Cycling

I believe finding heart threshold is important for a few reasons when it comes to your cycling training and racing.  The first and foremost reason is so I understand where my safe zone is without blowing up.  Secondly, and just as important as the first, is to set more precise heart rate training zones to follow in my training sessions.  Lastly, I use the heart rate threshold test to gauge myself over time as to the speed I can maintain at threshold.  I am not going to get into the science behind what happens when you push over threshold as I am still learning and there are way better resources out there than I for that information.  I’ll reference most of this as to how it impacts me and then share the process and tools that I use.

I should, mention that I do not currently own a power meter and that is why I use heart rate to set up training zones.  I would like to get a power meter, but I know it will snowball into a power meter for at least 2 bikes and that is a lot of dough.  I would really like a gravel bike and replace a few things on my race bike, which could all be done fro the price of the power meters.  That being said, a power meter would make zone training a lot easier, since your heart rate can be pretty variable.  Also, I just recently started paying more attention to specific heart rate training zones, as I am learning more about this and getting more serious about my training for next year.  Up until a couple months ago, I was mostly using the threshold for reasons #1 and #3.

Avoiding Blow Up

When I first started riding again in 2013, I just went out and rode.  I didn’t have a heart rate monitor and I didn’t ride very long distances.  I didn’t really know what I was doing, but I just enjoyed going faster and rode as hard as I could each time I went out.  I was usually riding fairly short rides and the Chequamegon 40 was a really big deal and a really long distance race for where I was at with my fitness at the time.  In 2014, I picked up my Garmin Edge 510 with a heart rate monitor and started watching my heart rate.  I found it fascinating, as I am a bit of a nerd and enjoy going back through the data.  That being said, I am not a big fan of collecting data, just to collect it.  My rule of thumb has always been that there is no point in collecting data, if you don’t plan on using it to make a decision or change a behavior later.  I have an engineering background and always used that rule of thumb in the engineering world as well.  Some people like collecting data just to collect.  I like to collect it to do something with it.  To be fair, sometimes you need to collect a bunch of data before you realize you can do something with it.

Back to avoiding blow up.  As I started to watch my heart rate, I was able to start seeing where the danger zone was for me.  Especially after riding some longer rides.  In 2014, I started the season off with a 4 hour XC race and a 32 mile XC race to prepare for the Lutsen 99er.  I blew up bad in both the 4 hour and 32 mile race and was able to go back and look at the heart rate data to see where things went wrong.  I was able to narrow down a window of where my threshold probably was, based on blowing up during those races.  Some of this blow up was lack of muscle endurance, but most of it was going out way to hard and pegging the heart rate too early and for too long and not being able to recover from it during the race.  The advantage of doing heart rate threshold tests, is that you can better narrow that window down as it only takes a few bpm over that threshold for too long to send you into a dark zone of not being able to recover.

Training Zones

Many training programs out there will reference training zones to train in and there are a few different ways to set up heart rate training zones.  You don’t actually need your heart rate threshold either, but you will set up more accurate training zones by using your measured threshold heart rate.  The most simple training zone calculation is based off of your max heart rate which is obtained by subtracting your age from 220 to obtain your estimated max heart rate.  Again, this is a rule of thumb as this just creates a ballpark of your max heart rate and nobody is the same.  Another way, is to use heart rate reserve, which takes into account your max heart rate and your resting heart rate.  Again, there are still assumptions in using this method, as it is still using the same 220 minus your age formula to calculate an estimated max heart rate.

Training zones at the end of day are a product of the calculation of data that you put into the formula.  We’ve all heard the saying, “garbage in, garbage out”.  If you can get a threshold number, you will make the calculation of your training zones more accurate, therefore giving you more accurate windows to train within.  As with anything, there is some variability still in getting your threshold heart rate from your own test, but it is a step in the the right direction to providing you with more accurate data.

Fitness Gauge

This is where using the same equipment and process each times comes into play, so you have a level playing field to compare test to test.  I like to compare my average speed from each threshold test to measure my improvements.  I am looking for an increase in speed at my threshold heart rate.  If I can put out more speed at the same heart rate threshold, then I know I am getting faster and stronger.  That being said, you also have to keep in mind what kind of form you were in prior to the test.  If you completed the test, but were severely fatigued going into it, then you certainly are not going to show improvements in speed over a previous test that you did when you were well rested and in good form.  It’s always important to compare apples to apples when you are looking at trends.

When To Do A Threshold Heart Rate Test

I have been following a lot of the methodology from Joe Friel in his book called The Cyclists Training Bible and making adjustments to fit it around me personally.  Everyone trains a little different and has different schedules, but I think it is fair to say that most people probably use the weekends for their long training rides and use the beginning of the week for recovery and build back up again to the weekend.  Maybe they throw a longer mid week ride in somewhere.  I have been playing around with different types of rides and training sessions in my recent off season rides, along with going back in time and reviewing impacts to my fitness & fatigue graph from various rides over time.

Making some assumptions and saying that you put in some long rides over the weekend and take a rest day on Monday, it seems like Tuesday could be the likely day to do a threshold test.  Tuesday may be your interval day or short ride with high intensity anyways and could be the perfect day to toss in a threshold test every couple of months, just to see where you are at.

Gear For Finding Heart Rate Threshold

I’ll list the gear I use along with the minimalist version of gear needed.

Road Bike – Same bike I use for all my road training rides and it will be permanently mounted to my trainer for the winter.

Minimalist – Use whatever bike you have available.

Heart Rate Monitor – I use the Garmin Heart Rate Monitor that came with my Garmin Edge 510 bundle.

Minimalist – You can manually measure your heart rate every 2 minutes and take the average of those measurements to obtain your threshold heart rate.

Bicycle Computer – I use a Garmin Edge 510, for all of my rides anyways and have it connected to my Strava and Training Peaks accounts.  It makes it real easy to go back and look at the data afterwards to see if my speed is increasing over time during the same threshold tests.  It also monitors my cadence during the test or any riding that I do.  Garmin did recently came out with an updated Garmin Edge 520 to replace the 510.

Minimalist – If you don’t care about comparing speed from test to test, then you can get away without this.  If you want to compare speed, then you would need a computer with a wheel speed sensor.  You’ll still need something to track time regardless.

Trainer – You can use any trainer you want, but I use the CycleOps JetFluid Pro.  If you want to compare speed from test to test, then it is important to use the same trainer for each test.

Minimalist – You can do this out on the open road, but you will need enough road for constant peddling with no stops.  Best to be fairly flat with minimal wind as well.  You can still use this method to compare speed from test to test, but there are always more variables when you are live riding.

Threshold Test Program – I use to use the Sufferfest Rubber Glove program because it has a specific warm-up built into it and includes the 20 minute test.  Using the exact same process each time makes comparison from test to test much more reliable. I have been putting together and now using my own test process as I always look for better ways of doing thing on my own.

Minimalist – Just something to watch the time.  You’ll need to do a warm-up before going into the test.  If you do some searching you will find suggestions for 20 minute and 30 minute tests.  Where you warm up before the 20 to 30 minute threshold test.

Training Zone Calculator – I use to use the Joe Friel Training Zone calculator within my Training Peaks account.  Now I am using the Andy Coggan training zone calculator, which is also in Training Peaks. I believe this is also available in the free version of Training Peaks.

Minimalist – Lots of options on Google.

finding heart rate threshold

Links and References

Book – The Cyclist’s Training Bible (affiliate link)

Sufferfest – www.thesufferfest.com

Training Peaks – www.trainingpeaks.com (referral link)

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