Building Your Aerobic Base
For an aerobic sport, such as running, building our base is the one of the most important aspects of our training. Building an aerobic base takes time and a lot of easy miles.
There is currently a trend in talking about “Zone 2” training and how important it is. Whatever term is being used, it’s not a new concept to have most of our training be at the easy aerobic level. Matt Fitzgerald hit on this with his book 80/20 Running, which refers to the fact that around 80% of our training should be easy aerobic volume. While the exact percentages may vary, anywhere from 75-85% of our training should be aerobic base training. Arthur Lydiard, a legendary running coach, championed the idea of base building phases in our training.
While intensity and speedwork are important for actually getting faster and improving efficiency, think of them as the interior work of a house. Base training is the foundation and framing that provides the bulk of the structure. It’s important that this training is “easy” relative to our hard sessions. Let’s talk about a few ways we can determine if we’re going easy enough:
1. Heartrate. Heartrate can be a good guide for us to keep our training easy. What zones are easy can be determined through a lab test (gold standard), field test, or just by extrapolating heartrate data from a standard training block (the most practical/useful). While a lab test gives us the most accurate results, it’s also just a snapshot of a test on one given day. Heartrate fluctuates depending on heat, altitude, hydration, and other environmental and non-environmental factors. We should have a sense of what our max heartrate is, and be at least 20% below that for aerobic base workouts.
2. Perceived Effort. Often called RPE (rate of perceived exertion/effort), this typically uses a 1-10 scale. 10 is the absolute hardest we can go, and an effort level we don’t need to tap into very often. 1 would be basic movements throughout the day: standing up, walking to the kitchen, etc. Most of our training should be in the 3-5/10 range. While it takes time to dial in our perceived effort, it can help us develop an accurate sense of how hard we are training on any given day.
3. Breathing. Similar to perceived effort, this is a way to check in with our effort using our breathing as a guide. In easy training, we should be able to converse comfortably and be able to string several sentences together without having to stop or adjust our pace. While some folks may talk about nasal breathing as a guideline, this is not necessarily as useful of a guideline for many people.
4. Lactate Reading. Probably the most accurate way to ensure effort, also the most complex. This is definitely the standard professional teams will use to ensure their athletes are training easy enough, especially during altitude camps. This requires special equipment and a way to draw a drop of blood during a workout. It can be useful, but definitely only for the most serious athletes.
So, what do we gain by going easy? It’s hard to gauge if we’re getting faster when we’re taking it easy a lot of the time. Think back to the foundation metaphor. We can’t build a solid house without a solid foundation. Aerobic base training builds that. It increases our capillary density, which allows us to transport more blood and oxygen to our muscles. It increases our mitochondrial density, which enables us to become more efficient at transporting stored energy (glycogen and fat) into output. Sustained effort at low intensity actually slightly increases the size of our heart and makes it a stronger muscle. This in turn can help increase our stroke volume which increases the amount of blood pumped into the system per heartbeat. Over time, with lots of volume of base training, we can often see max heartrate drop. While it does drop with age, base volume will drop it even more.
In short, it’s important to keep most of training in the “easy” category. This may mean choosing easier terrain for aerobic base or long runs. Walking and hiking can be great tools for ensuring that we can get enough time in an easy range to build the aerobic infrastructure. Next month, we’ll take a look at how we can actually get better at running!
