MAX HR Myth

Rich and I were just having a discussion over using a heart rate monitors as training aids.   I firmly believe this is a fantastic, necessary piece of equipment for training when used properly.   Most people have heard that you can figure your “Max Heart Rate” by subtracting your age from 220.   People even use this magic number for training.   For some (very)  limited amount of people, this may be OK, but for the majority of people this will not work for them.

If you are training, Lactate Threshold (LT) is the “magic number” that should be used for your training.   Each person has a unique aerobic/anaerobic threshold. That is a heart rate where we’re working very hard and our body switches from aerobic to anaerobic. When our bodies are working anaerobically, they are not using fat as fuel, but (I believe) only glycogen. This aerobic/anaerobic threshold is very close to our lactate threshold and for training purposes, many people use the terms interchangeably.

The GREAT thing about heart zone training is that you can increase your aerobic/anaerobic threshold so that you can work out at higher intensities while still being aerobic – and burning fat. The higher level you can work at while staying aerobic means you are burning more fat. Cool, huh?

So, where do we get this (LT) magic number from anyway?   Well, there are a couple of sources:

1) LT Testing in a sports lab

2) LT Field Testing

If you have a local  University with a sports lab, you may want to go the first route.   For the rest of us, we are stuck doing the LT field test, which, for the most part is fairly accurate.   The protocol is for a 30 minute workout where the 30 minute workout is  a maximum effort, and you can not go further than 30 minutes.  Your LT is the heart rate  average over the last 20 minutes of the workout.  You can do this easily on the bike or running with your heart rate monitor.  We are not going to cover the protocol for swimming at this point.  Here is an example for a LT Field Test for Running for us speed challenged guys:  If your 5k time is approximatly 30 minutes, run a 5k for your LT time trial.  This should at or near your personal best time for the distance, and you should complete the run feeling like you could not go any faster/further.  Start your heart rate monitor at the beginning, after 10 minutes, hit the lap button.  After 30 minutes (end of run), hit your stop button.  Your LT is the average heart rate over the last 20 minutes.  You can find your bike LT using the same methods, replace your running shoes with your bike…

OK, so we have this LT Magic Number, now what?  Using this number, you can determine your HR racing/training zones. 

Zone 1: Active Recovery    – 65%-75% of LT

Zone 2: Aerobic                – 75%-85% of LT

Zone 3: Threshold             – 85%-95% of LT

Zone 4: Lactate                – 95%-105% of LT

Zone 5: VO2 Max             – >105% of LT

You can see it’s easy enough to find what your training zones are using the above. For example, if your LT was 160, your zone 2 would be 136-144 (160 multiplied by .85 and .90).

To build your aerobic capacity, keep your HR in zones 1 or 2.  Zone 1 is for recovery runs/rides, while Zone 2 is where you will need to work on training for endurance.  By following the above recommendations you’ll be pleased at how quickly you make gains and will start to look forward to the LT tests.

If you feel you just MUST train with a heart rate monitor and you have NOT had LT Testing, ask me about the Mafftone Method.  This will at least give me a chance to talk you through the decision.

For more information, please read some of the articles below:

Coach Suzanne’s take on it:

http://steelcityendurance.com/index.php?option=com_content&task=view&id=22&Itemid=26

BeginnerTriathlete’s Take on it:

http://www.beginnertriathlete.com/discussion/forums/thread-view.asp?tid=25733&start=1