Heart Rates and Training

Heat rate (HR) is the number of times your heart beats per minute. Heart rate monitors have been around for a while now, and are a relatively easy way to monitor effort. As your effort rises so to does your heart rate.

Maximum Heart rate.

Maximum Heart Rate (MHR) is the highest you can get your heart rate up to. To measure this in your chosen exercise is difficult and quite uncomfortable. A typical test would be a 5min all out effort with a final all out sprint at the end (after a good warm-up) and see what your HR gets up to. But this is dependant on your motivation to go very hard, and how tired you are. Some people use a formula to estimate their maximum HR (eg. 220 – your age). But there is so much variation amongst individuals that I would not recommend using a formula to predict your maximum HR.

Lactate Threshold.

Lactate threshold, or Anaerobic Threshold, is the effort above which you begin to accumulate lactic acid. Lactic acid is the stuff that turns your legs to rubber when you try to go really hard. You should be able to maintain an effort at just below your lactate threshold Heart rate (LTHR) for between 20 and 50 minutes (depending on your fitness level). Your LTHR will change with fitness, different sports, fatigue, and numerous environmental conditions (eg temperature and altitude). You can get the LTHR measured in the lab, however it can also be estimated in the field, by simply taking the average HR for a time trial (say of 20-50min in duration).

Training zones.

Unfortunately there are a number of different representations for HR training zones. Some are based on percentage of maximum HR and some on your LTHR.

A number of sources recommend training zones based on a percentage of you max HR, or a variation of this (eg HR reserve – taking your resting HR into account). Due to the inaccuracy of obtaining your MHR, and in the variation in individual LTHR’s, my opinion is that HR zones based on MHR are broad estimates at best. I do not recommend these methods, as it is difficult to measure your max HR accurately and I do not know of any relationship between your LTHR and your max HR. HR zones based on MHR maybe far too hard, or far too easy depending on the individual, environmental conditions and various training effects.

Early on in a build-up an 85% effort based on max HR maybe above your LTHR (which is a very hard effort), when you are fitter 85% effort maybe quite comfortable when you have raised your LTHR.

My preference is to use 5 general training zones, with sub categories in the fifth, hard training zone. These training zones can be summarized in the table below.

ZONE Description Breathing % of Lactate Threshold HR Perceived Excertion (BorgScale1-20)
1 Recovery/Easy hardly noticeable 65-81 6-9
2 Aerobic slight 82-88 10-12
3 bb aware of breathing 89-93 13-14
4 Steady state starting to breathehard 94-100 15-16
5a Lactate threshold breathing hard 100-102 17
5b VO2 Max heavy, laboured breathing 103-105 18-19
5c Maximal effort! maximal exertion 106+ 20

This type of scale takes into account changes in fitness and environmental conditions. The only major problem, is that your HR zones will change as your LTHR changes – which means that you may need to regularly check on what your LTHR is (ie do time trials or testing at regular intervals).

Determining your Training zones.

As mentioned above, I prefer to determine HR zones based on LTHR. An easy way to determine your LTHR is to do a time trial that takes 20-50min (the fitter you are the longer it should be). If you take the average HR for the time trial – this is probably close to your current LTHR. You may start out slightly below, and end slightly above – if your pace judgment is good, but the average is a good guide.

From your test results, you can then multiply your LTHR by the percentages listed in the above table to get estimates of your training zone HR’s. These HR zones are valid for the conditions in which you did your test. If environmental conditions that you train in (typically) are significantly different to those that you did the test in, then the HR zones will not be that accurate. For example if you did a test in the Lab, where it is 30 degrees, and you are training outside in winter conditions of say 10 degrees, your training zones will be significantly inaccurate.

For most people, LTHR’s are different for different sports. Running is usually higher than cycling, and cycling is usually higher than swimming. So you need to test yourself in each discipline that you will be using your HR monitor, and set zones for each discipline as well.

Using your Training Zones.

So you have done the tests, and calculated the HR zones. What now? The whole point of using a HR monitor is so that you can be very specific with your training. So to that end, you need some sort of training plan, with some idea of what intensity you will train at for each session. If you don’t know what HR you should be training at – then there is little point in using the HR monitor in my opinion.

If you have a specific HR range that you are to train in – then you should set your HR monitor limits (if available) to that range. Many monitors have this facility, and can also tell how much time was below, within, and above the limits set (as well as average and maximum values). The time outside the desired range is more useful than the average HR for the session. If you are suppose to train for 1 hour between 130 and 145 HR, and the average is 140, that may appear to be a good workout. However, if the time above 145 was 20min and the time below was 15min, that means that for over half the session you were outside the desired training zone – and may well have had the opposite training effect than that planned.

The biggest mistake that most people make is doing the easy training too hard, and the hard training too easy. You should do the hard sessions hard (as prescribed in your training program), and note the HR you achieve. Your easy training sessions should have a significantly lower HR (20 to 50 beats lower!). I believe that a HR monitor is very useful for ensuring that the easy training is easy, and that athletes do not get carried away and go too hard on easy training sessions.

Another useful function for the HR monitor is to alert you when things are about to go wrong – either over training or sickness. If at your normal easy pace your HR is significantly higher than normal, and you cannot get the HR down, this maybe a sign that you have the first stages of an infection (eg virus), or are more fatigued than normal. Conversely if you cannot get the HR up very high – that is a good sign that you are very fatigued, or over trained – and it is time for rest!