THE HIDDEN HEART RATE ZONE
How to unlock the elusive ZONE 7 for optimal fitness
If you’ve used a smartwatch or health-tracking app for workouts, you’re probably familiar with the 5-level heart rate training zone system. This is the go-to method that most fitness brands use to allow users to utilize heart rate to gauge intensity. Within these categories, zone 1 is very light, zone 3 is moderate, and zone 5 is your maximum effort.
This approach has gained popularity for several reasons with one being its accessibility. Our brains like odd numbers and can handle breaking things up into 5 sections. From a perceived exertion point of view, it’s detailed enough to accurately break down each effort without being overwhelming.
While there’s nothing wrong with utilizing this trending system, it’s also important to realize that there are zones that exist beyond our current understanding. Today I want to break down what lies above zone 5 and teach you how to use it to maximize your performance in running and other endurance sports. Whether you feel like you’re hitting a plateau or simply want to gain more knowledge about exercise physiology, this is for you!
Let’s jump right in and start leveling up your training.
Optimize Your Physiology Through Zone 7
As we get into the fun stuff, I want to provide a couple of key disclaimers. While it’s important to know that these zones exist, I’m by no means claiming that everyone needs to be training at these thresholds. If you’re brand new to running, focus on getting out the door and slowly building up your volume. The advice below will be most relevant to upper-intermediate and advanced athletes who are looking for that extra 1–2% advantage to earn a new personal best or get under a qualifying standard.
I also want to point out that while this is targeted toward runners, it can be applied to several endurance-based sports such as cycling and swimming. Now with that out of the way, let’s dive deeper into what these mysterious top zones are all about.
HEART RATE ZONE GRAPH
While you may find that the image above looks a bit complicated and ‘sciency’, it’s quite simple if you break it down. I encourage you to think about zones 6 and 7 as a re-classification of zone 5. All we’re doing is dividing the top end of your effort into more detailed sections to get even more out of your body’s physiology. To help make this crystal clear, let’s look at each one individually. ⤵
Zone 5) V02MAX
Contrary to popular belief, the effort associated with V02max is not the absolute all-out effort that you’re capable of. This is simply the pace or effort you need to hold to arrive at your V02max which can usually be held for approximately 4–6 minutes. If you need a quick refresher…
VO2 = SV x HR x (a-v O2 diff)
SV = stroke volume (the volume of blood your heart is moving with each stroke)
HR = heart rate
a-v O2 diff = arteriovenous oxygen difference (how much oxygen the body is utilizing)
In layman’s terms, V02max reveals where your ceiling lies for utilizing oxygen to do physical work. The more efficient you get at this process, the longer you’ll be able to sustain a harder effort. This zone can be pushed forward by doing workouts like mile or kilometer repeats.
Zone 6) Anaerobic Capacity
This zone is usually between 90 to 95% of your absolute max effort. While training here, you’ll be so far beyond your LT 2 threshold that you’ll be recruiting an entirely different metabolism system (anaerobic metabolism) to produce adenosine triphosphate (ATP) through energy pathways that do not require oxygen.
While you may think that zone 6 would only apply to sprinters and middle-distance runners, it’s still very relevant to distance athletes. Your ability to kick at the end of a distance race will be ultimately governed by your pacing, nutrition, and how well-trained you are in this zone. This is also an extremely valuable area to develop running economy at faster speeds and build mental toughness.
To access this zone, consider doing 1min on, 2–4min off time-based intervals or 400m repeats on a track. It’s not exactly a pleasant threshold to be training at, but it’ll make you that much stronger both mentally and physiologically. As it translates to virtually any distance, it’ll be worth your time to train here regardless of what your next race is.
Zone 7) Neuromuscular Power
This last zone is far less about getting fit cardiovascularly, but rather about developing your ability to maximally recruit your neuromuscular system for better form, power, and endurance at top speeds. We’re now at 95–100% of your absolute maximal effort. As you can imagine, this is only a zone that should be touched on by more experienced athletes.
While there’s a valid argument that this type of work will be most relevant to sprinter cyclists, track sprinters, or 1500m runners, there is still a use for this in longer distances. It’s no coincidence why so many track athletes become legendary marathoners near the end of their careers. By properly developing neuromuscular power, you become a more efficient athlete who can use every single muscle fiber to get from point A to point B. This will have a transformative impact on your strength, gait health, and more.
If your legs are fatiguing near the end of a marathon, having a foundation of neuromuscular power built on top of a well-planned marathon training block can be the difference between achieving your goal or hitting the wall early.
Now you have to be super careful when training this system. It should only be touched on once every couple of weeks to allow your body to fully recover. If it’s within a marathon block, ensure you have easy days on either side. A couple of example sessions for improving zone 7 are to do 8 x 10s hill repeats (at least 6–10% grade) or 6–8 x 100–150m sprints on a track. Approach these workouts with caution and gradually increase their volume and intensity as you develop as an athlete.
In Closing,
There’s more to heart rate zones than your smartwatch is telling you. If you want to truly maximize your power, economy, and endurance as an athlete, it’s key to touch on zones 6 and 7 occasionally. While there’s no getting around how tough these thresholds are, the benefits waiting for you on the other side are vast and well worth your efforts. Are you ready to overcome your plateau and snatch that 1–2% training advantage that you’ve been missing out on?
You got this.
-DavidLiira.Kin
