Heart rate-based training – which essentially refers to the monitoring and manipulation of heart rate data during training – has been frequently used by endurance athletes for the past three and a half decades. One of the first sportspeople to pioneer its use in the late 1980’s was three-time Tour de France winner, Greg le Mond. In more recent times heart rate-based training has made its way into team sports and other domains.
The key to successfully implementing heart rate-based training is to know how to use it and in what context it can be used successfully, as well to possess a keen awareness of its inherent limitations. In this article we explore this training tool under some key headings.
HOW TO TRACK YOUR HEART RATE
First off, heart rate-based training requires the use of a device which can accurately record your heart rate and give you real time feedback. The most tried and trusted method is to wear a heart rate strap which is synced to an electronic device such as a watch or a phone (although I do not advocate carrying the latter during training). The strap should be worn snuggly across the lower part of your chest (not too loose and not too tight), with the electrodes facing inward. The electrodes need to be dampened prior to use, so as to obtain an accurate reading. Another key consideration is that the electrodes need to be washed regularly in warm sudsy water, as sweat accumulation can easily interfere with the signal (I find it necessary to do so after every 4-5 uses). Finally, the heart rate monitor (the centre attachment) should be unclipped when the strap is not in use, so as to preserve the life of the battery.
Wrist based heart rate monitors – which are in-built into your watch – have entered the market in recent years. It must be noted that these can be wildly inaccurate, something which is highly undesirable when accuracy is absolutely paramount. They may be slightly more effective when the watch is worn on the underside of your hand. However, this can feel very strange, and the jury is still out as to whether they are effective when worn this way
KNOW YOUR MAXIMUM HEART RATE
Knowledge of your maximum heart rate in beats per minute (BPM) is critical to the successful implementation of heart rate-based training. Without it, or without a comprehensive lactate analysis, we cannot accurately identify the heart rates zones that you should be training in (we delve deep into these heart rate zones in the next section).
The Karvonan formula (220 – your age = your maximum heart rate) is often deployed in an attempt to ascertain a person’s maximum heart rate. However, it may well be one of the most unreliable mathematical equations ever formulated. While it will predict many people’s maximum heart rate within a band 2-3 BPM, it can also err by up to 30 BPM.
Instead, you can accurately ascertain your maximum heart rate within a couple of BPM by completing a structured ramp test on a treadmill, or if this is not possible, a 1000m or 1200m time trial can be useful alternative. The tricky part is that you have to push yourself to exhaustion during such tests, and therefore they must be very carefully positioned within your wider training schedule.
IDENTIFY YOUR TRAINING ZONES
This is where we start to incorporate heart rate into your training schedule. There are generally considered to be five training zones, and although there is no clear dividing line between zones, having a clear idea of the zone into which each training session falls is critical to the successful implementation of heart rate training. Let us take a look at each of the zones in turn.
Zone 1 (active recovery/very low intensity aerobic) = <65% of maximum heart rate
This zone is exactly what it says on the tin. It is the lowest intensity at which you can run, cycle, swim, etc. It is debatable as to whether a trained sports person at any level can obtain a physiological benefit (outside of active recovery) at a heart rate that is less than 55% of maximum heart rate. Nevertheless, exercising at between 60%-65% of your maximum heart rate can confer as much aerobic benefit as exercising at 75% of your maximum heart rate.
Zone 2 (low intensity aerobic) = 65-75% of maximum heart rate
If you are an endurance athlete, then the majority of your training should be performed in this training zone, as it builds your base and acts as the foundation for gaining improvements at higher intensities. As a coach, I have found heart rate to be enormously beneficial in guiding my clients to stay within the confines of this zone. Train in this zone regularly.
Zone 3 (extensive aerobic) = 75-85% of maximum heart rate
Unless you will be spending a significant proportion of time in this zone during competition, then it can often be considered a bit of a dead zone. By this we mean that it confers little additional benefit compared to training in zones 1 and 2, and can reduce the quality of key training sessions in zones 4 and 5. However, do not dismiss its importance if you are training for a marathon, half Ironman triathlon, etc.
Zone 4 (intensive aerobic/anaerobic threshold) = 85-90% of maximum heart rate (but can only be accurately determined via lactate testing)
You can check out an earlier blog post for a comprehensive discussion about this crucial training zone. It corresponds to the highest intensity which your aerobic energy system can sustain independent of your anaerobic energy system. This turning point, known as your anaerobic threshold, generally lies between 85 and 90% of maximum heart rate for the vast majority of people, but can only be accurately pinpointed via a well interpreted lactate test. Knowing the precise heart rate at which this occurs can be hugely beneficial, as it can often be counter beneficial to exceed this heart rate when performing training sessions designed to raise your anaerobic threshold.
Zone 5 (Anaerobic) = >90% of maximum heart rate
This zone encompasses anything from your anaerobic threshold, all the way up to your maximum heart rate. Whenever you perform an effort where you feel that your lungs are burning or your breathing is laboured, then you will be somewhere within this zone. It can be exceptionally difficult to control your heart rate once you exceed your anaerobic threshold, and therefore, I am not a big proponent of using heart rate to influence the precise intensity when training in this zone. Instead, such efforts should be governed by perception of effort or by pace, with heart rate playing a more minor role.
Cognisance of the limitations of heart rate-based training is critical to its successful implementation. These limitations fall into two main categories:
The first is that there are a whole multitude of factors which can lead to a heart rate reading that does not equate to the effort level which you are exercising at. These include stress levels, caffeine use, hydration status and even your pre-session fatigue levels. In such instances, we need to be very careful when interpreting heart rate readings as they can very easily skew our training. Moreover, there can be occasions where a heart rate monitor provides an inaccurate reading independent of any outside variable. This can be quite common at the start of an exercise bout, where an abnormally high reading is more frequent than an abnormally low reading.
The second key limitation is that there will be a heart rate lag at the start of every effort or repetition, during which time your heart rate gradually catches up to mirror the intensity which you are exercising at. This is most pronounced during the first intense effort during a training session – where it can take up to a few minutes for your heart rate to catch up – while the time lag lessens in duration on subsequent repetitions. For this reason, heart rate-based training is often unsuited for repetitions that are of a short duration. Moreover, even on longer repetitions, you can easily overshoot the desired intensity at the outset if you actively strive to run to set heart rate.
RESTING HEART RATE
The common resting heart rate for a semi-active individual is around 70 BPM, while it is usual for endurance athletes to have a resting heart rate in the 40’s or even the 30’s. For a considerable period of time, an individual’s daily resting heart rate was considered to be an accurate barometer of their freshness and readiness to train. In more recent times, this view has come to be largely discredited. Yes, it will often be the case that an excessively large deviation from your mean resting heart rate will suggest that you should not train, or should only train very lightly, on that given day. However, if your resting heart rate happens to jump by 20 BPM, then in all likelihood you will be acutely aware that you feel unwell, regardless of whether or not you have knowledge of your resting heart rate at that particular time.
In the past decade, heart rate variability (HRV) has been shown to be a more reliable tool at predicting your readiness to train. This metric measures the amount of time in between heart beats. The greater the variation in time, the greater your physical readiness to perform. One drawback to HRV is that it is much more difficult to measure than your resting heart rate. There are a variety of apps and watches which can perform this task. Nonetheless, to be measured correctly, such data must be obtained first thing in the morning, and having such devices on your bed locker may not be desirable.
FINAL TIP – HEART RATE MONITOR SHOULD BE THE SAME MAKE AS YOUR WATCH
Although most heart rate monitors and GPS watches will indicate that they are ANT+ compatible, and should therefore be able to work with a monitor or watch designed by a different company, this is often not the case. Avoid any unnecessary hassle by purchasing a heart rate monitor and watch which are manufactured by the same company.