Determining Your Training Zones

Lactate Threshold (LT) or Anaerobic Threshold (AT) is the heart rate at which you begin to accumulate lactic acid in your muscles – where anaerobic energy production surpasses aerobic.  It is the rate at which the effort is no longer sustainable for long periods of time.  This generally occurs at 85-92% of MHR.  Various cycling coaches use different number of zones.  I use six zones and they are listed below, and are based on percentage of your anaerobic or lactate threshold.

Heart Rate Zones:

Zone 1 = Recovery (<71% of AT) – uses the aerobic system
Zone 2 = Endurance (72-81% of AT) – uses the aerobic system
Zone 3 = Tempo Pace (82-91% of AT) – uses mainly aerobic system
Zone 4 = Threshold Pace ( 92-102% of AT) – uses mainly aerobic system with some anaerobic system
Zone 5 = Anaerobic Pace (103-110% of AT) – covers zone where aerobic converts to the anaerobic system.
Zone 6 = Maximum aerobic capacity (Too short to record HR) – anaerobic and CP systems

Your cardiovascular output can also be measured with power if you use a power meter on your bike.   Similar to heart rate, there are also power zones.  These are based on your Threshold Power (TP), as estimated from the test given below.  My  six zones are shown here for power, and are based on those of Hunter Allen and Andrew Coggan.

Power Zones:

Zone 1 = Recovery (<55% of TP) – uses the aerobic system
Zone 2 = Endurance (56-75% of TP) – uses the aerobic system
Zone 3 = Tempo Pace (76-90% of TP) – uses mainly aerobic system
Zone 4 = Threshold Pace ( 91-105% of TP) – uses mainly aerobic system with some anaerobic system
Zone 5 = Anaerobic Pace(106-120% of TP) – covers zone where aerobic converts to the anaerobic system.
Zone 6 = Maximum capacity (V02 Max) (>120% of TP) – anaerobic and CP systems

How to estimate your AT or TP:

AT and TP is the maximum sustainable pace you can maintain during a time trial effort that lasts about an hour.  However, it’s possible to estimate this heart rate or power from a shorter 20 min time trial effort.  Find a road that is relatively level and free of traffic and intersections.   You may need to find a road that’s about 5 miles and do an ‘out and back’ course to get your 20 min test done.   Alternately, you can do this on an indoor trainer.  In some ways this gives you a more repeatable result as you don’t have the weather and traffic variables.  Warm up thoroughly,  then begin the 20 minute time trial.  Ride as hard as you can at a pace you can maintain for the full 20 minutes.  There is a fine line between going out too fast and not pushing yourself hard enough.  You may need to do a few of these before you figure out your sustainable pace.   Record your heart rate and/or power toward the end of the 20 min.   Do not accelerate or sprint at the end.  What we are after is your sustainable heart rate or power.    If you have a computer that allows you, take the average heart rate or power for the last 5 minutes of the effort.   

The pace you can maintain for 20 min is slightly faster than the pace you can maintain for an hour.  So take your heart rate or power from this 20 minute test and multiply by 0.95 to arrive at your sustainable pace, which is your estimated Anaerobic Threshold (AT) or Threshold Power (PT).   Use this value to estimate your own zones as described above or using the table below.

These power threshold zones and method for determining them are based on those advocated by Allen and Coggan in their book, ‘Training and Racing with a Power Meter’.

Refer to these charts to determine your zones based on your own AT or TP values obtained from your test:

All the best in training!
Coach David Ertl
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David Ertl is a USA Cycling Level 1 (Elite) Coach and NSCA Certified Personal Trainer.  He coaches individuals interested in improving on their current cycling ability, whatever level that may be.  He also provides cycling training plans and ebooks at his website:  www.CyclesportCoaching.com            
He can be contacted at Coach@CyclesportCoaching.com

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