Using the Critical Power 30 Minute (CP30) Assessments to Create Custom Heart Rate Zones

By setting Zones customized to your body, heart, and systems, you get a true view of your level of effort you are currently training or exercising in, which allows you to train better, without injury over longer times.

Critical Power 30 Minute assessments are one of the best ways to determine heart rate zones without a laboratory, and is the best assessment in the apps for that purpose.

But it also takes the most personal effort.

With a Heart Rate Monitor (HRM) you can use it to develop Heart Rate Training Zones. With GPS and/or Foot pod in Running, it can be used to develop Pace Zones too.

To calculate a VO2 Max and FitRank (age adjusted ranking based on VO2 Max) for these assessments, you must have a Resting Pulse entry in the Health section of the app (one not taken from a Blood Pressure reading). See this post on measuring your Resting Heart Rate.

The CP30 does this by measuring your Lactate Threshold Heart Rate (LTHR) and/or your LTHR equivalent pace, and setting your personal zones based around that number.

The Critical Power 30 Minute (CP30) assessments are not meant for those who are not used to physical exercise. This test requires you to run for 30 minutes as fast as possible (race pace).

How to do the CP30 Assessment:

  • Find a track or very flat area you can run along unobstructed for 30 minutes. You should run alone and at race pace (it has been shown that running with others affects the test and actually makes you faster). Ideally this should be a constant pace, that you can hold through the end of the 30 minutes without slowing down.
  • Warm up for 10 minutes (light walking, stretching, etc)
  • Start the assessment on your App, and start running at race pace – Choose Run > Workout > CP30 Running Test
  • After 30 minutes, the workout ends and the recovery portion will begin (recovery is an option we’ve added here as another data point to assess your overall change in fitness – the better the recovery, the better the cardio fitness). Stand still and relax for 2-minutes.
  • Your results will be on the final screen, as well as online at and in your results listing. The assessment in the app allows you to easily set the calculated zone set from the assessment as your default zone set.

The CP30 assessments also help determine Pace Zones applicable to running – similar to heart zones and used for training, they can help your training and keep you injury free by keeping your training in the right zones at the right times, without a heart monitor. You can watch these zones change over time with changes in your fitness! In fact, this assessment should be used on a regular basis to show changes in your fitness levels and training zones.

How We Calculate Zones and VO2 Max:
Heart Rate Zones and Pace Zones are determined using the formulas provided for this type of test. One of the best write-ups of these calculations is the Joel Friel post here. For VO2 Max, we take your Resting Heart Rate and your calculated Max HR leveraging the assumption of your LTHR being ~85% of Max HR, and using the Heart Rate Ratio Method. (Eur J Appl Physiol. 2004).

Many factors can influence results including temperature, elevation, sleep, emotional state, eating habits and more. The best analysis of the results are by comparing it with previous results. The test environment should remain as constant as possible.

Please don’t perform any fitness test without talking to your physician about it first.

Assessments can change the way you live your life, change the way you exercise because:

1. They help determine your Fitness Level.

Using physical tests developed over the years by a variety of individuals and institutions, these fitness tests have been shown to result in fairly accurate measures of fitness, and can be compared to others of similar age and gender. Not all assessments in Fitdigits apps have the ability to determine VO2 Max, but the majority do.
See the article “Why Should You Know (and Track) Your Fitness Level?” for more.

2. They help determine personal heart zones.
People are all different. Only 20% of people have a max heart rate that is close to the 220-Age = Max HR. For a large majority, setting zones of 50%-100% off that formula does not result in zones that are meaningful or correct. From previous discussions, we know how important understanding what HR zone you are in can be towards realizing your goals (is your goal endurance and fat burn, or speed and power, for example). Your HR zones will also change over time – the more fit you become, the higher your HR Max will be (relative to yourself, not others) for example. Not all assessments in Fitdigits apps have the ability to set HR zones, but the majority do when paired with a heart rate monitor.
See the article “Why Should You Know Your Personal Heart Rate Zones?” for more.

13 thoughts on “Using the Critical Power 30 Minute (CP30) Assessments to Create Custom Heart Rate Zones”

  1. Would think that you could do this on a rower if you're fit enough. My running blows (bad knee) so my body breaks down before my heart. On a rower, I average much higher HR (and rowing is harder than running generally if done hard enough because it's cardio and lifting simultaneously). Also would think that things like Insanity or Boot Camp classes would work too (as long as there's no long breaks).

  2. This is typically considered a field test (outside test) but as a trainer, i would like to know if it can be performed inside on a treadmill too. As myself have had injuries to my knees & ankle, and so have some of my clients making some tracks hard to keep a constant pace for 30 min. Also same with temps. where i live. On a treadmill, i have no problem due to less impact of a non-hard surface. I am still researching it for the answers for all of us. Though, i do not get this option on the android version.

  3. has anyone heard back from digifit about the question? Also, i don't use a footpod, i use a fitbit that that reads into icardio that tells the distance i go, so is a footpod actually needed?

  4. you should be able too. It is listed under "others", cycling and the all the other exercises listed. But i think with out having something to read the distance into it, it won't work. Has anyone heard back from digifit?

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