Making sense of heart rate training
Heart rate monitoring can be an awesome addition to your training. Not only can it provide you with crucial information to optimise your workouts, it can also be used to monitor your progress and adaptations to a plan, as well as most systems having a great community element, helping you to keep motivated throughout your programme.
That said, most people use HR training completely wrong, and the lines get blurred between what’s a “great workout” and what’s a “random, unfocused workout”.
I’ve added a reference to a phenomenal paper on energy systems, so feel free to check that out for the nitty gritty of energy system training, but this is an overview of practical considerations.
Here’s how to avoid the mistakes, and get the most out of your training by tracking heart rate data.
What’s the best system?
Before we dig into this game changing topic, there’s a bit of housekeeping. We will start with systems. Apple, Polar, Garmin, MyZone, Strava, and plenty of other popular systems exist to help you to get the most out of your training using heart rate.
All have pros and cons. The main thing to consider is why you’re using heart rate data in your training. The most detailed systems for endurance performance (Garmin, Polar, etc) tend to offer more precise information (including recovery suggestions, VO2 max data, threshold data, and more) to the ones focused on the community element (such as MyZone). With some systems, you can link your Heart rate monitor to both (for example, Myzone and Garmin), so this is worth checking out for the best of both worlds!
Are watches or chest straps best?
Popular devices such as apple watch, fitbit, whoop and more can give a decent overview of your heart rate throughout your workout, and tend to have the added benefit of being more comfortable and something you already have on!
However, for more accurate data, chest straps will tend to offer more value. Again, if you’re just getting started with this, either may be fine: weigh it up with what’s suggested for the system you’re using. If you have an apple watch and just want to use that, you can track your workout on apps such as strava that offer a lot of detail with a very easy set up. If it’s community focused, myzone needs a chest strap so you have a better chance of having accurate, up to date data live in the classes. If you want more accuracy, an up to date, high level chest strap monitor is going to be the best option, as systems like polar and garmin will need a lot of accurate data to run the calculations and give suggestions.
The Heart Rate (HR) Zones
Probably the main benefit of using heart rate tracking is the ability to manipulate energy systems. Different “heart rate zones” are intended to target different energy systems, allowing you to balance effective training and recovery, and to focus on the adaptation that will give you the most benefit towards your goals.
Systems like MyZone make this really easy (although we will discuss the potential issues a little later). Here’s how it works on myzone, and what the thresholds mean (so other systems make sense):
- Blue zone (60-70% Max HR) for mainly aerobic work (some people still call this the FAT BURNING ZONE, as this is where oxidation of fat tends to peak)
- Green zone (70-80%) correlating with close to aerobic threshold work (where we start to transition to more carbohydrate metabolism). Here we’re producing some lactate, but able to get rid of it without significant build up, and can usually still maintain the intensity for long durations
- Yellow zone (80-90%) being around the anaerobic threshold (where this lactate build up begins to exceed clearance, and we’re only able to sustain this intensity for a limited time)
- Red Zone (90-100%) maximal effort work– can only maintain for short durations (depending on personal thresholds and IMPORTANTLY, the accuracy of your MAX HR which is set on the system!
You may notice I’m not giving exact numbers here, and individual thresholds may vary into the next “zone”. The way this system works is %MAX HR, which means it’s in the range of these limits, but not exact. More advanced software, or of course individual testing, can give you numbers much closer to exact for these individual limits, and give you a better understanding of your training. More on this later.
Top 3 mistakes made with HR training
1. Red Zone is NOT always the best option
Each of these thresholds targets a different pathway, or energy system, for you to work on, and all of these systems can be important. Here’s the big mistake: people going “ALL OUT” on every training session, thinking the only successful sessions are the ones around maximum effort.
This is simply not true, and for most people starting out, this range should be used sparingly.
Working at the lower ranges, say green zone on myzone, or around the aerobic threshold (70-80% max HR) should be predominantly fuelled by the aerobic pathways, and is a great range to work in between high intensity sessions.
True high intensity work should only be used 2-3 times per week in trained individuals to ensure they have the capacity to fully recover between these sessions. If training 6 days per week, alternating the high and low intensity sessions is crucial.
A good tip for well-trained people is to try to balance higher intensity and lower intensity work (for example, 4 days per week would be 2 higher intensity sessions (say 1x 5km run at threshold, 1x recovery run at 70% HR, rest day, 1x intervals session (4x 4 minutes at max intensity) and 1x low intensity tempo recovery session (intervals with HR around 65-70%).
With people less well trained, starting out with a lot of “low intensity work” can ultimately allow far more training time, lower recovery demands and far higher adaptation- particularly with the high stress lifestyles most of us currently lead! Working in the max effort zones is NOT always the best option.
2. Training for points or Calories makes no sense.
For me, this is a huge problem. At some point, we’ve managed to move value away from the key elements of a workout, and move towards tracking their effectiveness on “Calories” or “points”. This needs to stop.
Now, I’m not saying Calories don’t matter. Energy balance (or Calorie balance) is a huge element of successful training plans, whatever your goal, and having an idea what we burn in a workout can be helpful to plan nutrition.
The problem is when we put value to this. Every training session should have a goal, and I believe this should NEVER be Calories burned. Here’s why.
Once you put stock into burning calories in your training, training becomes exercise, and ultimately, that exercise becomes pointless. Why? Because you can achieve the same “energy balance” by adjusting the other side of the equation, and eating less food. This leads to a whole host of problems, but I wont get into it now. Just know that the Calories you burn ONLY matter in the scheme of planning nutrition, and are a by product of the training session, not the goal of it.
So, Points then. MyZone uses this systems as MEPS, but every system has their own scorecard and points. Don’t get me wrong, points can be great short term to motivate people to start exercising, but beyond that there’s not much value in it- certainly not enough to have any impact on your training plan. So, don’t chase them.
Plan your sessions based on what adaptations you want. Want to be better at burning fat? We can do that. Want more energy day to day? We can do that. Want to improve fitness? Yep. All great goals that we can plan a session towards. None rely on points or Calories.
3. Using HR for resistance sessions
I’ll keep this short. Heart rate should not be a key way to monitor your resistance session. We’ll talk about this in more detail in the section on limitations, but crucially, most gym work isn’t designed as a CV workout. It’s simply the wrong measurement tool. We’re in the gym to build muscle, or move better, or get stronger, and HR can’t monitor this.
Never adjust your resistance session based on HR data, unless of course it’s intended as a CV session with weights. In that case, first off, ask why it’s not just a CV session? No right or wrong, just sound reasoning is needed.
Limitations with heart rate data
1. Having an inaccurate max HR estimate
Most systems do not require a test for max HR, and work out an estimation based on specific formula (such as 220-age= HR max estimate). Often, these formulas are specific to the software, and therefore not consistent across board. That’s not much of a problem, as for the most part, we will be using one device. The problem is, that these estimations may be significantly different to your true max HR. In this case, it can be an issue, especially as max HR can be used to calculate zones (% max, %HR Reserve) and more.
Often, systems will update themselves with a “new max” to avoid this issue, but that leads to the potential of inaccurate measures and a max HR that’s upated due to a “glitch” rather than a reading. I’d love to say it doesn’t happen often, but it’s something to watch out for.
Of course, we can test for max HR, but for the most part, this is reserved for well-trained people endurance athletes as accurate max HR data will provide huge benefit, and the stress of testing should be something they are relatively comfortable with.
2. Having an inaccurate anaerobic threshold estimate
Building on the above, a far more adaptable number to max HR is the anaerobic threshold. At this point, there’s a sudden rise in blood lactate, and ultimately a rapid increase in fatigue. The good news is that this is highly trainable, and good training will push this closer to your max HR, meaning you can work harder for longer.
The problem then, is that this threshold moves. Therefore, for less trained, this point may sit around the mid 70% max HR, all the way up to the high 80% max HR. In this case, working out at 80% max HR for 20 minutes can be a VERY DIFFERENT workout for 2 individuals (or even the same person before and after training). One session is low intensity, aerobic dominant, the other is high intensity anaerobic dominant!
The irony here is this: The person who needs the lower intensity work (new to training) is pushing the high intensity zone, and the person who needs to push more for adaptation (well trained) is in the recovery zone.
Again, we can work this out on an individual basis with direct and indirect tests, but most advanced systems do a pretty good job at estimating lactate threshold, providing it’s individualised to you.
3.Tracking supramaximal intensities (sprint work, etc)
Building on the section for resistance training, any work above the intensity of HR max (where we are predominantly focused on anaerobic, alactic pathways (such as jumps, sprints, etc), HR is again the wrong tool to use.
For sports such as football, you may see an average HR, but this can be deceiving, as HR average may be around 65%, but overall intensity may be far higher, and need extended recovery time due to the amount of high intensity, neuromuscular loading with the short sprints, sharp turns, etc. HR can be used here, but should be used in addition to other methods of monitoring to have a sense of the true workout intensity. For sprint training and other speed, power or strength dominant sports, with very short, very high intensity efforts (under 10s) and long recovery (4+ minutes), HR is not a useful tool.
Other uses for HR data
HR can also be used to estimate health and fitness, with measures such as resting heart rate, HR recovery and by monitoring average HR for specific training sessions. It can also be used as an indicator for overtraining, or as a useful way to match exercise intensity if your usual mode of training is not available (eg when injured).
HR can be a great tool to help coaches, athletes and fitness enthusiasts to take more control of their training, and enhance adaptations. This will lead to better programmes, better workouts and better results, but only when used effectively, and with a reasonable understanding of the accuracies and inaccuracies of different methods/ systems.
Understanding the difference in zones is key, and ensuring the you take full advantage of this is a great way to help you to maximise results. Calories and points measures are less useful, and HR monitoring for supramaximal intensity work such as sprint work or resistance training is simply the wrong method to use.
Want to dig into this a little more? Here’s a great paper on the topic.
Buchheit, Martin & Laursen, Paul. (2013). High-Intensity Interval Training, Solutions to the Programming Puzzle: Part I: Cardiopulmonary Emphasis. Sports medicine (Auckland, N.Z.). 43. 10.1007/s40279-013-0029-x.
Josh Kennedy MSc, ASCC, CSCS