This article is about how to approach Aerobic Base Training, specifically for endurance runners. If you are looking for an article about the benefits of Aerobic Base Training instead, then please read Run Slow to Run Fast and then come back here to develop your aerobic base. Endurance runners are defined as anyone training for 1500 metre races and upwards.
- What is Aerobic Base Training?
- Why is Aerobic Base Training important?
- How do I do Aerobic Base Training?
- How much Aerobic Base Training do I need to do to improve my running?
- If Aerobic Base Training is an “Effort Level”, what happens to my pace?
- How long will it take to improve my Aerobic Base?
What is Aerobic Base Training?
Endurance runners use a mix of energy systems, but relying predominantly on the aerobic energy system, which is when energy for running is produced fairly slowly by burning carbs and fats in the presence of Oxygen. Thus “aerobic”. Aerobic Base Training is any exercise that makes you more efficient at producing energy aerobically. You are building a “base” of aerobic fitness upon which the rest of your training will depend.
Why is Aerobic Base Training important?
Building your aerobic base is important for runners because the better you become at using energy from aerobic processes, the faster or longer you can go before other non-aerobic energy systems become dominant. Other energy systems, for example the lactate energy system, provide energy a lot faster, but cannot be sustained nearly as long as aerobic energy, so the more you can rely on aerobic energy the better, so you can run faster and / or longer.
How do I do Aerobic Base Training?
The best way to do Aerobic Base Training is by exercising at an easy effort level. It’s therefore critical to figure out where your easy effort level lies.
If you exercise at a very low intensity, it still sort-of counts as aerobic base training, but it’s not an optimal use of your running time – you won’t get as fit as quickly as if you’d got the effort level right.
If you exercise at too high an intensity, at higher effort levels too much of the non-aerobic energy systems are used, so:
a) you don’t get as much adaptation to be great at aerobic energy production, and
b) it’s not sustainable because it takes longer to recover from the high efforts and you can’t do as much total exercise.
You won’t get as fit as quickly as if you’d got the effort level right.
So the first step is find that optimum easy effort level. Are you an experienced runner that can run for 75 minutes, and have a heart rate / gps device? If so, you should do a heart rate drift test. This will help you determine the heart rates associated with your optimal easy effort level.
If you are still starting out on your running journey, then there are other ways; a good indicator that you are running near your aerobic base pace, and one that doesn’t require a sports watch, is that you are able to have a conversation, so running at a “conversational pace”. My favourite method to see if runners are running easily enough is this:
“Can I say a sentence of about this length out-loud while running without gasping for breath in the middle?”
I’d expect you to gasp for breath at the end for sure, but if you HAVE to take breaths in the middle of the sentence, you are putting in too much effort / going too fast for the run to be optimally building your aerobic base.
Another way to get a good idea of your aerobic base effort is to use the Runningversity training pace calculator and input your recent 5K flat-out race time. The calculator will provide your aerobic base pace. If you run at that pace for a few runs, you’ll get an idea of what the effort level FEELS like so that you can replicate that same feeling in future runs without even looking at your pace. Think about the amount you have to breath. Think about how your legs feel. Think about how hard you have to pump your arms. Think about your stride.
Alternatively, if you know your real maximum heart rate (not guessed), then you can use the best heart rate zone calculator to find your Zone 2, which is where your aerobic base effort lies. HR zones go from 1 to 5, where 1 is the easiest and 5 is the hardest.
If you aren’t sure of the best method for you, ask in the comments below.
How much Aerobic Base Training do I need to do to improve my running?
Now that you know the effort level required to be in your Zone 2 aerobic training zone, you can check it against your current running plan. For endurance runners, the majority of your training should be focused on the aerobic energy system. If you run 5 times a week, at least 3 of those runs should be developing your aerobic base. If you run 3 times a week, at least 1 of those should be developing your aerobic base.
The other runs in the week will be much faster or harder speed-work days (assuming you are ready for that), like Tempo or Intervals or Hills.
If Aerobic Base Training is an “Effort Level”, what happens to my pace?
You may have noticed that if you run at a constant pace, after a while into your run, your heart rate will start to rise and the effort will feel harder. It’s likely that if you started in your Aerobic Base Training heart rate Zone 2, if you keep up that pace, your effort level will rise enough to take you out of the optimum aerobic base building zone.
Therefore, it’s perfectly valid to run gradually slower through an Aerobic base run. If it’s a long run, you might find your finish pace is 30 seconds slower per mile than the pace five minutes in from the start of the run.
As you get fitter and build your base, you’ll notice that the point at which this drop-off in pace will happen later in the runs, and additionally the rate at which your pace drops off will improve (to a slower rate).
How long will it take to improve my Aerobic Base?
How long will it take to build aerobic base for running? Improvements to your Aerobic Base will be noticeable within 4-6 weeks. You’ll notice that for a any given easy effort, your heart rate and pace combo will be better. So if you run at a certain easy pace, your heart rate will be lower, or if you run at a certain easy heart rate, your pace will be higher.
You’ll also notice that when you run fast, like in a 5K race, you’ll be able to sustain a higher pace throughout.
Your aerobic base will build long term over many years.
Here’s an example of three runs that I did over five months, all at 140bpm average heart rate (and as close to 140bpm as possible during). During that time, I was exclusively doing base training – not something I’d recommend normally, but it was a fun experiment. Look at how the pace got faster and faster:
Run 1: 21.4 miles, 3h26m, 9:40/mile average pace (baseline run).
Run 2: 21.7 miles, 3h20m, 9:12/mile average pace (after 3 months).
Run 3: 21.8 miles, 3h06m, 8:32/mile average pace (after 5 months).
As you can see, in 5 months, my pace at that heart rate improved by over 1 minute per mile! And the point at which my pace started to slow came later and later as the months went on.
Aerobic Base Training summary
To do Aerobic Base Training runs, run at a super easy effort level and if you are an endurance runner, make these the majority of your training.
Keep going consistently for months to see big improvements.
Be prepared to drop your pace if your effort level starts to creep up outside of your Zone 2, but remember to do some much faster running for a short while each week.
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