Monitoring your training intensity and workload is an art form and we have lots of toys which can help us to achieve it successfully. A lot of runners have GPS devices and heart rate monitors, the cyclists amongst you may have a ‘power meter’ to measure your output in ‘watts’. So, what’s the best toy to use and how should it be used to gain the most benefit?
Intensity and Output
Understanding the difference between intensity and output is the most important thing so before we go any further, let’s just clarify how exercise intensity differs to exercise output.
- Intensity is simply how hard your body is working. You can measure intensity by checking your heart rate, your breathing rate and perhaps the most reliable gauge, perceived effort (PE). Perceived effort is the posh term for ‘how hard does it feel’. You can only measure how hard your body is working from physiological markers, whether that be your breathing and heart rate going through the roof, or your brain telling you that you can’t go any harder!
- Output is the performance achieved as a result of your exercise intensity. For example, whilst running you may feel as though you’re working really hard and your heart rate may be close to maximum (that’s intensity). A quick glance at your fancy watch tells you your running speed is 8 minutes per mile (that’s your output). Alternatively, you might head out for a steady cycle ride and your heart rate and breathing rate might be considered to be ‘moderate’ (that’s intensity) and your cycle power meter shows 190 watts (that’s your output).
Aren’t they the same?
No, absolutely not. Let’s be really clear that output measurements are not measurements of how hard you are working.
Example 1:
You head out for a run and your plan is to run 5k hard, but due to a hard week of training, your legs don’t feel great. Nevertheless, you crack on and push your heart rate up to the planned level for that session. You may feel as though you’re working as hard as you should be and your heart rate is at it’s planned level, but because your legs are simply tired, your 5k time is slower than normal.
Question: If your heart rate is at the correct level and you feel as though you’re working hard, but your 5k pace is slower than normal, are you running at the right intensity?
Answer: Yes, you are at the correct intensity.
Example 2:
You travel abroad for a cycling holiday and find yourself cycling at high altitude. Whilst completing a training ride your heart rate reaches the correct level and it certainly feels like you’re working as hard as you normally do. However, due to the altitude, your power output (watts) is lower than normal.
Question: If your heart rate is at the correct level and it feels like you’re working at the correct level, but your power output is lower, are you cycling at the correct intensity?
Answer: Yes, you are training at you target intensity
To be fair, scenario 1 is more likely, as not many of us jet-set to altitude on a weekly basis, but I’m sure you get my point. Sometimes, your intensity can be high (heart rate, breathing and perceived effort), but power and speed are lower. Irrelevant of you power and speed, the simple truth is, if it feels hard, then it is hard and if it feels easy, then it is easy.
Your point is?
If you use ‘output’ to gauge your training, then that means your intensity in some circumstances may be wrong. If you use a gps watch and running pace to gauge your training, you’re choosing output and not intensity to gauge training. If you’re a cyclist and you use either speed or power to dictate training, you too are choosing output and not intensity to gauge your training.
Some people choose to do this, which is fine, so long as you understand fully the difference between the 2 and the potential pitfalls. Strava has a lot to answer for… Nobody looks at Strava to see whether you ran at the correct intensity / heart rate, they only see the speed you completed the run or ride. As a result, people constantly look at their watches and try to beat their previous times or achieve a certain speed.
Training is about intensity
Training is designed to place a stress or load on your body. As a result, you get an adaptation response and your fitness subsequently improves. To measure the training ‘stress or load’ you need to know how hard your body is working, or the ‘intensity’ of the workout. Therefore heart rate, breathing rate and perceived effort (how hard does it feel) should be used frequently to measure your intensity.
Performance is about outcome
Here’s the catch. If you want to improve your performance, race faster or gain a personal best, the simple truth is that you need to run at a certain pace or cycle at a certain power output. For that reason, outcome measurements such as speed or power give you clear benchmarks for improvement in key sessions, but they should be less frequent. For example, every 4 weeks, you may attempt to run a 5k as fast as you can, or measure how much power you can produce over a 20 minute period. Using outcome has it’s place, but it’s not something you should be using every day.
You can’t perform all the time
So this paragraph is the crux of this blog post. It’s important to understand that OUTPUT measurements, are a gauge of your PERFORMANCE. So if you choose to use output such as a power meter or running speed, to gauge your daily training, you are ‘testing yourself’ every single day. Even if you think you’re only training, having a number in front of you which constantly tells you your output, means that you are measuring performance and that’s simply not healthy, either physically or mentally.
There’s 3 things to consider here:
- You can’t be at your best every single session. It’s impossible. In fact, why would you even want to be at your best every session? As the saying goes, the only important performance is on ‘test day’ or ‘race day’. Your performances in training will fluctuate from week to week. Linear improvement every week does not happen.
- If you train to output, you may train at the wrong intensity. For example, what happens if the session says ‘run at 8 minute mile pace’ or ‘cycle at 250 watts’ and you’re having a bad day and feeling a little tired? You’ll push way too hard to achieve the pace/power and train at the wrong intensity, causing even greater fatigue.
- From a psychological perspective, it ‘messes with your head’. Constantly fighting to hit the correct pace or power and feeling as though you’ve failed when you don’t. The pressure of having to ‘perform’ every single session, for both yourself and (if you’re on Strava) for others watching. It can be the absolute killer of joy. If your plan says ‘run easy’ then simply go and run easy, switch off your GPS so you don’t even know how fast you’re running. Why would you add that pressure to a potentially enjoyable run?
Let’s summarise
Use intensity to guide your sessions. If your plan says ‘long easy run’ then use your heart rate monitor to stay in zone 1, hold a full conversation and ask yourself… does this feel easy? You should NOT look at your average pace or try to run at a specific speed, running speed is irrelevant for day to day training. Every few weeks, it’s fine to test yourself and see if you’re making progress. On those days it’s fine to use output as a measurement. Go to Parkrun and see how fast you can complete the course. Finish time and average minutes per mile are measurements of performance.
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