Why you need to be in the zone
Fitness & Thinking Fridays: inspired by the runners among my clients
“Cardio” is the last thing I prescribe to my clients looking to lose fat or drop inches. But when we do add it into the plan, I stress the importance of Zone 2 training for longevity in and outside of our work together, as well as for improving one’s general cardiovascular capacity.
But what is “zone two”, how does it contribute to aerobic fitness and how could it count against you when you’re trying to tone up? Let’s take a look together and introduce you to two people I’ve worked with who’ve changed their approach to running and fat loss since working with me.
What is “Zone 2”?
Zone 2 activity represents a continuous and low-intensity endurance pace, typically moving at 60 to 70 percent of your max heart rate. Also known as “aerobic base training”, zone two involves exercising at a sustained and moderate effort level where you can comfortably maintain a conversation or even sing to yourself. Because of its low impact nature, it's a sustainable and effective training modality for those embarking on running journeys.
And let’s note it here: for some people, just walking quickly will elevate their heart rate to this level – any movement that raises your pulse can count, your speed is incidental!
Our bodies perform optimally when they can efficiently use oxygen. This is because oxygen assists in clearing lactic acid from our bloodstream and tapping into stored fat as fuel, essentially both aiding recovery from exercise as well as promoting fat loss. As our heart rate climbs above 70 percent of our maximum heart rate, statistically, we’ll begin to use less oxygen, we cross into anaerobic training, which can result in a build up of lactic acid and contribute to fatigue, increased hunger and even a greater injury risk.
So, if your heart rate exceeds 70 percent of your max when you step the pace up in a zone two session, you should slow down – even if that means “just” walking! Over time, your heart rate should come down both generally and as your speed increases – but it takes practice!
Benefits of training in Zone 2 over time
Your heart gets stronger and larger, enabling it to pump more blood with each beat.
On a cellular level, your mitochondria – the “powerhouses” of our cells responsible for generating the energy required for all of our bodily processes – increase and become more efficient.
You shouldn’t be out of breath and so can focus more easily on maintaining proper form.
Zone two sessions can be almost meditative, soothing both mind and body.
Zone two training and fat loss
A quick fact check: you’ll often read that zone two cardio is “fat burning” – some of my inspirations while researching and writing this article claim this too, as will ChatGPT – and while this isn’t wholly wrong, essentially, if you’re not in a calorie deficit, which is to say eating less food than you need to maintain your weight over a couple of days, then you won’t lose any more fat overall as a result of keeping your heart rate in this range.
Moreover, cardio can spike people’s appetites and so I’d hate for you to increase your activity in this way, only to overeat and land at calorie maintenance or even in a surplus and see no aesthetic benefits for the extra work you’ve put in.
Indeed, I would only use cardio for fat loss once you/we have established a regular meal plan and weightlifting regimen.
When Pete, Beth and I caught up on their training weeks, they’d both and independently of one another sheepishly tell me about how they just had to go quicker because it was so boring going so slowly. And yet, when they committed to keeping their heart rates lower, their fat loss efforts improved as did their running times, and, further, how hard they felt they were working seemed to decrease too.
In week eight of our second block, Pete set records in and out of the gym and credits the slower sessions with him feeling more capable when he runs as well as better recovered in between running sessions.
How to determine if you're in Zone 2
Heart rate monitors are typically the easiest way to determine if you’re in Zone 2. The most reliable monitors are those with a chest strap, but wrist models or watches that take your pulse will work too.
Speed is a bit trickier due to external factors that can influence it, but it’s an option if you don’t have a heart rate monitor. Your Zone 2 speed will be below your 'tempo' speed. Make sure to factor in your pace per mile or kilometre with your Rate of Perceived Exertion (RPE) to ensure you’re in Zone 2. For us, this is typically a conscious 6/10 effort at closer to a jog than a sprint speed.
While heart rate monitors are useful, understanding the combination of heart rate, speed, and perceived exertion is the ultimate goal. A simple test is to see if you can repeat the phrase, "I'm having the best time ever," without struggling or pausing for breath.
If your heart rate is sky high even when you run slowly, you might feel the need to walk to bring it down – which my clients who love running hate to do! But trust, do your best to stay in Zone 2 when you’re running a Zone 2 specific session. Over time, you’ll need to walk less; slower movement can also be seen as an opportunity to work on your running form, which could increase your efficiency and so reduce your heart rate.
Even if you’re training for a race in two months and haven’t done much Zone 2 work, it’s beneficial to start now. Seasoned runners can still benefit from revisiting Zone 2, and new runners should spend all their time here to build a strong aerobic base, even if it means a walk/run race.
You might feel like you’re not working hard enough when your heart’s in this zone, but you will get faster. Professional endurance athletes spend over 80% of their time in Zone 2, building a foundation for natural speed development.
Recommended Reading
"All About Zone 2 Training," Pittsburgh Runner, accessed August 4, 2024, Pittsburgh Runner.
“Best exercise to lose belly fat”, BHF, accessed August 8, 2024, British Heart Foundation
“Zone 2 cardio is the secret fitness weapon hiding in plain sight”, GQ, accessed August 4, 2024, GQ magazine
Leanne’s journey: steps are the new cardio!
Over the last 12 weeks, Leanne’s dropped inches, kilos and misconceptions about what it takes to feel and look fantastic.
4kg down, 4cm lost around her waist, and her hips measure the same but with more shape through her back and hamstrings, the difference in her confidence and physique has only climbed. Leanne’s gotten stronger and clearly built muscle all while getting leaner: her journey is the epitome of toning up.
In our last check-in of this block, Leanne wrote: “Yeah I’ve seen some amazing changes both physically and mentally which has been fab. I’ve noticed I don’t default to junk food and take-aways when stressed like I used to and building in healthier habits like a walk to destress.”
Also because we didn’t jump in with big changes things like getting my steps in has got a bit easier because we built up gradually. The result of weight loss whilst gaining strength has been exactly what I want.”
Leanne could have potentially dropped more fat if she’d eaten less and did more cardio and yet, where hunger was climbing as the weeks rolled on, if we’d increased cardio while further decreasing her calories, the resultant hunger could well have driven her towards take-aways like it used to and so undo a week’s worth of calorie deficit and fat loss.
And instead of comfort eating, Leanne found herself walking. Intuitively, she was using zone two cardio to manage stress and contribute to how she wanted to look. Cardio was something that we added in as late as possible – nutritious and filling foods and steps formed a good 75% of Leanne’s progress; cardio likely accounted for at most 10% of the results she saw.
If you’re wanting to become a better runner and/or achieve the figure of your dreams, respond to this newsletter with the word “RUN” and we’ll pick the conversation up around your specific goals!
And that’s it from me!
I’ve just landed in Ho Chi Minh City and have already been blown away by the hospitality and egg coffee.
Much love and I’ll see yas in the next one
Jack x