Cardiorespiratory training, usually referred to as ‘cardio’, is one of the most popular methods of exercise because it’s easy to do with very little equipment unlike some other forms of training. Most people think of cardio training as simply going outside for a run or participating in a group HIIT class a couple of times a week but there are various types of cardio training to be considered that lead to unique and specific benefits.
Cardio training is broken down into five categories (called ‘zones’) based on your heart rate (HR), which signifies the intensity of the exercise. Unfortunately, the different zones of training aren’t commonly talked about in mainstream fitness media and individuals often get ‘stuck’ training in a certain zone because they always run at the same pace or do the same HIIT classes week after week. In this post, I’m going to dial in on the benefits of Zone 2 training specifically, as this is where most of your training should be concentrated.
Before I do this, it’s important that you understand how to estimate your max heart rate (HRmax) so you can apply the information to come.
HRmax Calculator: 220 – age; (so for me 220 – 24 = 196 beats per minute (bpm) which is my estimated HRmax)
*There are various other HRmax calculators out there that may be slightly more accurate, but we’ll stick to the above for simplistic sake! Remember, this is just an estimate. If you have a recent datapoint (possibly from a Fitbit or Apple Watch) where your HR has gone higher than this number, use that to estimate your Zone 2 HR range instead!
In the graphic below, you’ll see the five heart rate training zones alongside their target HRmax with a brief explanation of the benefits of each. While future posts will dive into each of these, this post analyzes Zone 2 training -- indicating activity within the 60-70% range of your HRmax*.
*image from TriGearLab
*Refer to your HRmax above and now estimate your Zone 2 range by doing the following:
Lowest HR for Zone 2: 0.6 x HRmax ---- (for me: 196 x 0.6) = 117.6 bpm
Highest HR for Zone 2: 0.7 x HRmax ---- (for me: 196 x 0.7) = 137.2 bpm
Therefore, my Zone 2 training heart rate range is roughly 118 – 137 bpm.
Exercise physiologist experts recommend that somewhere between 60-80% of your overall cardio training should fall into the Zone 2 category because of the significance of the benefits (outlined below). First, let me explain how to know if an exercise is meeting the Zone 2 requirement.
The easiest way to confirm you are maintaining a Zone 2 level of training is to use a wearable HR tracker such as a Fitbit, Apple Watch, Garmin, etc. These allow you to periodically check in during the activity to ensure you are falling somewhere in that 60-70% range.
If this isn’t feasible, a great tool to use is the “talk test”. This simply means that during Zone 2 training, you should be able to maintain a conversation with someone during the activity. If you find yourself breathing too heavily to talk, this is an indicator that you need to pull back the intensity.
If you train alone and this means you must talk to yourself every few minutes, so be it!
Benefits of Zone 2 Training
Zone 2 training is driven by oxygen consumption and utilization. While you aren’t here for a biochemistry lecture, this is critical to our health as it allows us to become more efficient at utilizing the oxygen we breathe in and leads to all the great benefits mentioned below.
Fat Burning Capacity
To use fat as an energy source, our bodies require sufficient oxygen which Zone 2 training provides for. Due to its relatively low intensity, Zone 2 training is an optimal training type for fat burn. What’s even better? As we engage in it more often, our bodies become more efficient at using those stubborn fat stores as fuel.
Heart and Lung Health
Participating in Zone 2 cardio increases the efficiency of both the heart and lungs through a very similar adaptation. With the increased demand for oxygen, our hearts adapt by increasing the amount of blood pumped per beat known as stroke volume. A higher stroke volume allows more oxygen to be transported to tissues while decreasing the need for a rapid increase in heart rate to do this job. Speaking of the heart, zone 2 training has time and time again been shown to reduce the risk of heart disease – something far too commonly seen today.
Similarly, the lungs adapt to the increased demand for oxygen by increasing the amount of air they can take in per breath cycle. As you can imagine, this has very similar benefits to the increase in stroke volume and allows us to exercise without being limited by shortness of breath.
Blood Vessel Density
Whether or not we always recognize it, our bodies are extremely intelligent. Zone 2 cardio puts an increased demand on our muscles to consume and utilize oxygen for energy production purposes. As we know, oxygen is transported in the bloodstream and there’s no better way to increase the amount of oxygen delivered to our muscle tissue than increasing the sheer amount of blood vessels surrounding them. Yes, we can in fact increase the number of blood vessels we have (which may come as a surprise) and this is exactly what happens when Zone 2 cardio training is prioritized in our weekly routines.
Insulin Sensitivity
As mentioned in a previous HIB post titled ‘Daily Movement’, insulin is a chemical produced by our pancreas that moves glucose from the bloodstream into our tissues, including muscle tissue. It does this by bringing a glucose transporter to the surface of tissues that essentially sucks the glucose out of our blood. Exercise (muscle contraction) stimulates the movement of glucose receptors to the surface of the muscle WITHOUT the need for insulin which is a very good thing!
Low Impact / Recovery
Due to the low-intensity nature of Zone 2 training, you don’t need much time to recover from it making it a great option for in-between strength training or higher-intensity cardio sessions! As it enhances blood flow to the muscles, it can actually speed up the recovery process from these other forms of exercise which is where the term ‘active recovery’ comes in.
It’s important to note here that as famous fitness coach Ben Bruno likes to say, strength training should be thought of as the entrée whereas cardio training is a side dish. Although both should be done on a weekly basis, don’t let the benefits of cardio training cause you to neglect getting in strength work! Of course, this recommendation is meant for the average person and not those training for long-distance races, as things are quite different in that case!
How to get Zone 2 Cardio?
- Brisk Walking (includes incline treadmill walking)
- Jogging
- Swimming
- Biking
- Elliptical
- Rower
- Circuit Training (light weights!)
How many minutes per week?
Experts recommend getting at least 120 minutes of Zone 2 training per week to receive the bulk of its benefits. This might sound like a lot initially, but it can just mean getting out for a brisk 20-minute walk or a slow jog after dinner each night of the week. Simple, easy, effective!
Note: If you have the ‘all or nothing’ mindset, don’t apply it here! Strive to get at least 120 minutes while also understanding that getting anything is better than doing nothing. There isn’t anything magical that happens after 120 minutes is reached — it’s just a benchmark to strive for!
If you have any questions about Zone 2 training, please leave a comment or email me directly!
Quote of the week:
“Motivation is what gets you started. Habit is what keeps you going” – Jim Ryun
DISCLAIMER
- This is NOT Medical advice. Consult your medical professional before starting any supplement, diet regimen, or workout program.