Nordic Ski Racer - cross country ski racing    
Home  |  Racing |  Training |  Rollerskiing |  Trails |  Weather |  Equipment |  Forums |  Photos & Video

How to Train
Different Ways to Determine Training Zones

Heart rate training zones are used as a guide to maximize the benefit of your training. Each zone is used for training or developing a specific physiological response. Low heart rate zones are mainly for developing aerobic energy sources and pathways; higher zones may develop the anaerobic pathways or the ability for the body to clear lactic acid.

Using Maximum Heart Rate. If you don't have a handy physiology lab, there are alternatives ways of finding those zones. The easiest is to use percentage of maximum heart rate. Unfortunately, depending on who's book you read, the percentages and the number of zones vary. For example, Brian Sharkey ("Training for Cross-Country Ski Racing") defines four zones, starting at 70% of max heart rate, but Rob Sleamaker and Ray Browning ("SERIOUS Training for Endurance Athletes") have five zones, starting at 60% of max heart rate. Let's compare the two methods:


Alternative methods of using max heart rate 
to estimate training zones.


% of Maximum Heart Rate
Use "220 - your age" as a rough estimate of your max heart rate. 



Sleamaker & 

Zone 1 -   60-70%

Aerobic energy sources
Aerobic energy pathways
Capillary density
Mitochondria proliferation
Free fatty acid mobilization

Zone 2 70-85% Aerobic energy sources
Aerobic energy pathways
Slow twitch muscle fibers

Aerobic energy sources
Aerobic energy pathways

Zone 3 85-95% Aerobic energy pathways
Recruit FOG fibers
Aerobic glysolysis
Oxygen transport system
76-80% Aerobic energy pathways
Recruitment of FOG fibers
Aerobic glysolysis
Oxygen transport system
Zone 4 95-100% Anaerobic energy pathways
FG fibers
Anaerobic glycolysis
81-90% Aerobic energy pathways
Anaerobic energy pathways
Recruitment of FOG fibers
Anaerobic threshold (AT)
Oxygen transport system
Lactic acid clearance
Zone 5 100% Anaerobic energy sources
Anaerobic energy pathways
Fast twitch fibers

Anaerobic energy sources
Fast twitch fiber recruitment
Speed & neuromuscular coordination

Although the zones and percentages vary, there are many similarities: Aerobic sources and pathways are improved at lower heart rates; anaerobic sources and pathways at higher heart rates. We'll talk about the differences in the final section of this article...

Using VO2 Max. If you have results from a physiology test, you can use more precise methods to determine training zones. The training zones I've been using since June were determined from testing on a treadmill during a XC Oregon physiology lab test in June (more information about that test here). The physiologists used a combination of VO2, Heart Rate, and Lactic Acid levels to determine my training zones.

Sleamaker and Browning also use a method that plots heart rate against VO2 utilization to determine training zones. Essentially, they use the following method to determine training zones: From a graph that plots VO2 against heart rate, find the heart rates that match up to the table below to determine training zones:


Sleamaker and Browning Method of using VO2
against Hear Rate to Determine Training Zones


VO2 Max

Zone 1 55-65%
Zone 2 66-75%
Zone 3 76-80%
Zone 4 81-90%
Zone 5 91-100%

Comparing Methods. Using my max heart heart and the results from my physiology test, let's compare the alternative methods:


Comparing Methods of Computing Zones
Mike Muha's max heart rate = 174 


From Physiology Testing

Using Max Heart Rate


XC Oregon
Lab test

Sleamaker & 
Browning Method

Sharkey Method

Sleamaker & 
Browning Method

Zone 1 - 115-129 - 104-122
Zone 2 115-138 129-140 122-148 123-131
Zone 3 139-159 140-150 148-165 132-139
Zone 4 160-164 150-162 165-174 140-157
Zone 5 165-174 162-174 174 158-174

What a mess! Zones and heart rates are all over the place! Which method is the best to use?

I have several thoughts.

  • First, the use of a physiology test is very personal and provides the best results.
  • Second, a physiology test that uses more variables to determine zones is better than one that uses fewer variables.
  • Third, it's generally better to err on the side of going too easy than going too hard.

Based on these two criteria, I'm using my results from the XC Oregon physiology test because it takes into account VO2, heart rate, AND lactic acid levels. Sleamaker & Browning's method based on just VO2 and heart rate comes fairly close and is my second choice. S&B's Zones 1 & 2 match up almost exactly with XC Oregon's Zone "2". The main difference is in Zone 4 where S&B could have me training at too low a heart level. Based on my experience, I can do intervals in the 160-164 heart rate range without getting totally trashed.

How do the different zones translate into percent of max heart rate for me?

Zone Heart Rate
Range from
 XC Oregon 
physiology test
Percent of 
Max Heart Rate
(Max = 174 bps)
Sleamaker & 
Zone 1  -   - 60-70%
Zone 2  115-138 66 - 79% 70-85% 71-75%
Zone 3  139-159 80 - 91% 85-95% 76-80%
Zone 4  160-164 92 - 94% 95-100% 81-90%
Zone 5  165-174 95 - 100% 100% 91-100%

And what if I didn't have the results from a physiology test? I think I'd have followed S&B's method over Sharkey's. Sharkey's 148 beats at the high end of Zone "2" is just too hard for long slow distance - I think S&B has a more realistic range. At Zone 4, it's probably still better to train less hard (S&B) instead of doing intervals up to my max heart rate.