Setting your HR Zones & How to Judge Progress

We’ve been discussing how Lactate Threshold trumps Max Heart Rate for Endurance Training (LT over Max HR) and in the last post I explained how to test your Lactate Threshold (Test your LT)

Once you have done the two step test and properly determined your Lactate Threshold you will be able to set your training zones as follows:

  • Zone 1 – Recovery: Below 80% lactate threshold
  • Zone 2 – Aerobic: 80-90% lactate threshold
  • Zone 3 – Tempo: 90-99% lactate threshold
  • Zone 4 – Lactate Threshold – 100%-104%
  • Zone 5 – VO2 max: 105% – Above lactate threshold

Equip your watch (and connect your heart rate straps) to record data for zone training. 

Re-testing lactate threshold every 2-3 months (depending on the fitness age of the athlete) is required as zones will need adjusting as fitness improves, meaning your field tested data stays accurate and allows for fully robust training sessions. 

As you improve your aerobic fitness, you would expect your average heart rate during a 30 minute lactate threshold time trial to decrease. 

This is because the heart becomes more efficient at pumping blood and oxygenating the muscles as cardiovascular fitness increases.

There are a few key reasons why heart rate at lactate threshold pace decreases with training:

  • Increased stroke volume – The amount of blood pumped per beat increases, so the heart can deliver more oxygen at a lower heart rate.
  • Improved diastolic filling – More blood fills the heart between beats, boosting stroke volume.
  • Increased capillary density – More blood vessels in the muscles allow better oxygen extraction.
  • Greater mitochondrial density – More cellular mitochondria let muscles utilize oxygen more efficiently.
  • Enhanced fat burning – Greater reliance on fat metabolism and less on limited glycogen stores.

The cumulative effect is that the cardiovascular system can sustain a given pace with less effort and lower heart rate.

So if you see your lactate threshold heart rate dropping over time, it’s a good sign you are building robust cardiovascular fitness.

About Liza Smith

Liza: The Endurance Expert – Unlock Your Peak Athletic Potential!

Dedicated to endurance, particularly in extreme events like Ironman, OCR and Ultras, Liza stands out not just as a coach but as an emblem of determination and tenacity.

With a reputation for moulding winners and transforming raw potential into prowess, Liza is the top pick for those aspiring to reign supreme in their sport.

Liza’s coaching philosophy centres on the power of the mind. Her five pillars – Control the Controllable, Find the Positive, Focus on You, 100% Effort, and Extreme Ownership – guide athletes to both mental and physical excellence.

Whether you're just starting out or vying for the gold, Liza ensures your hard work delivers results. Train with Liza and unleash the ultimate athlete within you.