Have you ever wondered when you might use Zone 5 training? Is Zone 5 cardio valuable? Let’s find out what it means and why you should indeed include it in training at every age.
Heart rate training zones are ranges of heart rate between our resting and maximum heart rate. There are five of them. In order to determine our zones, we have to know both of those other numbers first.
These zones then correspond to different intensities.
Here I’m going to focus entirely on Zone 5, but we have talked extensively about these numbers in a variety of articles. You can learn how to train by heart rate, how to calculate your maximum heart rate and what is a good resting heart rate.
But where does Zone 5 fit in to everything? As you can see by the percentages below, this is going to be a small range of 90-100% of our MHR. This correlates to a maximum, all-out effort or what you might be hitting late in a 5K and 10K.
You’re probably wondering when we would use this? Should we ever be in Zone 5? Is it even possible for us mere mortals to get there? Are there any benefits to hitting Zone 5?
Keep reading to learn more!
What is Zone 5 Heart Rate Training?
Zone 5 is 90-100% of our maximum heart rate. That sounds intense, doesn’t it? Well, that’s because it is.
As I said, there are five zones and each correspond to varying intensities of effort when running or doing other workouts too. Zone 1 (50-60% of max heart rate) and Zone 2 (60-70% of MHR) are where we should spend the majority of our training based on the 80/20 principle of endurance training. These are low intensity efforts at conversational paces and where we lean on fat for fuel.
Zone 3 cardio (70-80% of MHR) is considered moderate level effort. It can be easy to spend most of our time in this zone, but this can lead to overtraining. However, it does have its place as part of the 20% of higher-intensity training we need to do.
Then there’s Zone 4 (80-90% of MHR). This zone is where you increase your anaerobic tolerance. It’s a hard effort and where our bodies use carbohydrates to fuel us. Again, this should be done as part of that 20% of training.
For endurance runners, you won’t be spending much time in Zone 5.
BUT that doesn’t mean you shouldn’t be spending any time there. You absolutely should have some sessions that push you to your max.
When I say only a little bit of time, I’m talking like 5 minutes total of a training session. When in Zone 5, you’re going all out. You shouldn’t be able to talk and you shouldn’t be able to sustain this effort for very long.
An all out sprint can be done for no more than 30 seconds.
You might be able to stay in this zone for up to 10 minutes at the end of a race, but in workouts we’re using it for short, sharp intervals.
While elite runners may be able to be in this zone longer because of their training, they still aren’t spending a lot of time in this zone. Even for sprinters, the total volume of time here is small compared to their overall training. But they may not adhere to that 80/20 rule.
When Will You Hit Zone 5?
You’ll find you’ll encounter Zone 5 in a couple of instances. It’s often referred to as red lining and you’ll absolutely know when you’ve hit it.
For example, many of us will find we hit Zone 5 doing hill sprints. Hill repeats tend to be short in duration so our heart rate may hit Zone 5 and then quickly back off during our recovery sets. You may also hit Zone 5 doing a high-intensity track workout.
Another place you may find yourself hitting Zone 5 is at the end of a race, specifically that last mile or so of a 5k when you’re going all out in that sprint to the finish line.
Other times?
- Plymoetric workouts with burpees, box jumps, high knees (still might not get there with these)
- Tabata workouts – again short hard push, then recovery
- Track workouts at faster than mile pace
- Mile time trial or race
- Final push of a big race
You should NOT be in Zone 5 when you are running strides, during goal pace miles, tempo runs or near the middle of any race over 1 mile.
As you can see from these examples, if and when we find ourselves in this zone, we are only there for a short period of time.
When Should You Use Zone 5?
As noted, we want to include some Zone 5 cardio workouts in almost every training plan. ALMOST because this isn’t something we need to do as beginners or when training for any first time distance race.
However, after that we will benefit from it particularly as we age, as we work on endurance, speed or any other goal.
- Only after you have a solid base of training
- Part of a variety of speed workouts
- For endurance athletes, likely only an occasional speed session
- Might occur weekly with just a couple minutes of plyometrics prior to a speed workout
Benefits of Zone 5 Training
This short but focused time results in some serious benefits, which is why we don’t want to skip it. This is the most common thing that gets over looked with our runners over 60 or marathon runners, but it is so useful when applied correctly.
#1 Improve Your VO2 Max
While I’m not super focused on this number for most athletes, there are some benefits to improving it (including overall health). By increasing this you will improve your body’s ability to intake, absorb, utilize, and process oxygen, and manage exercise-induced waste.
I.e. clearing out that lactic acid we often hear about. But remember that you are working at such a high level, your body is going to force you to slow down because it just can’t clear it all.
#2 Running Economy
When you’re running all out, you’re trying to run as fast as possible as efficiently as possible. This helps you improve your running economy, which includes foot turnover, speed, and power.
In other words, you can’t mentally be thinking about it, your body simply has to learn how to be more efficient. That’s exactly what we want, to just have the body know how to respond when we’re ready to push.
This can help at the end of a race during that sprint to the finish when you’re trying to save every last second you can for a PR.
#3 Fast Twitch Muscle Fibers
We all have slow twitch and fast twitch muscle fibers. Slow twitch are the fibers that allow us to go at a steady pace for a long time. We use these in the lower zones and as endurance runners, we have a lot of these.
Fast twitch fibers use anaerobic energy systems, are used for power, and fatigue more quickly. We use these when we sprint and run hills. We tend to lose function in these as we age.
However, by doing workouts that put us into Zone 5, we engage these fibers, increase mitochondria and this ultimately helps us maintain them as we age. They cannot be maintained without usage and are important! Not just for your running, but needing to quickly step off a curb, catch yourself, twist because a grandkid throws a ball at you.
#4 Mental Toughness
The final piece that can’t be ignored is how going hard changes you mentally. It gives you a new idea of what’s possible. AND it gives you a chance to see how you react when really and truly gutting it out.
Just having that experience prior to the end of a race can be enough to help you hang on with a finishing kick when every cell in your body wants to stop.
Factors Affecting Heart Rate
You might be wondering if it’s not possible to get to Zone 5 or if you can end up in Zone 5 more than you want to? The answer is yes to both questions as there are a number of things that can affect our heart rate, both at rest and when working out.
- Fitness – Heart rate training is great at helping us improve our fitness. You may notice, especially if you’re a newer runner, that you may find your heart rate heading into the higher zones more easily than seasoned runners. As you gain more experience and fitness, your heart rate zones may shift and change and you’ll be able to perform at a higher level but with a lower heart rate over time.
- Temperature – Warmer weather and high humidity can also affect our heart rate, causing it to rise more quickly than it might during cooler times of year. The body has to work hard to cool itself and as a result your heart is working harder.
- Medication – Certain medications can impact our heart rate, specifically some are designed to keep our heart rate from spiking, for example. This may mean heart rate training isn’t the best option for people taking medications that can impact how the heart functions.
- Illness – If you’re recovering from an illness, you may find that your body feels like it’s working harder than it usually has to in order to perform at the same level as before. This should only be temporary and it’s important to give your body time to heal fully.
There are other additional factors like stress and lack of sleep that may also impact your resting heart rate, which in turn can impact your heart rate zones. It’s important to keep all of these in mind if you’re using heart rate to guide your training and you’re seeing and feeling differences that are unexpected.
Hopefully this Zone 5 heart rate training guide gave you some better insights to what it’s all about.
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