Getting Z2 training right

Daniel Mason • 12 March 2026

Getting Zone 2 Training Right – The Foundation of Polarised Training

Run Slow to Run Fast

For the last 5 years or so I have been using low HR training methods to form a solid endurance base for myself and for my athletes – The results have been fantastic, though the initial switch was hard to master. It is never easy changing your running style to accommodate a new training regime and keeping your HR in check on a group ride can be frustrating when you reach the hills. Initially for me my 30 to 60 min runs were almost a minute slower per kilometer than what I was used to, I also had to walk to keep the HR down on the inclines but after around three months I was almost back to my running speed but with a HR of around 15 beats lower - 18 months down the line I was running as fast as I was previously, if not faster, but can keep the HR down whilst doing so, even on runs of over 2 hours. Over long runs or rides with a constant effort you will see heart rate raise (cardiac drift) the challenge here is to accept it and slow down to keep your heart rate under control, given time this naturally improves through polarised training. Cycling efficiency has also improved, especially on the inclines, it is all about building the engine, refining it and enabling it to be as efficient as possible.

Heart rate training incorporating polarised training methods of 80% relatively easy effort and maximum 20% hard efforts is not followed as much as it should be. This is due to most athletes wanting to or having the mental need to push too hard on the easier sessions to feel they have benefited form the training. This then leads to the athletes not recovering from the easier sessions and not able to push hard enough on the hard sessions. You can still utilise power meters and pace, but over time if you follow HR method then the power number will go up for the given heart rate rather than heart rate becoming lower for given power as you get fitter meaning the strain on the body is less and the training stagnates rather than improves.

In recent years HRM’s (Heart Rate Monitors) appear to be much more reliable and with the rise in smart watches they have become a daily monitoring system for many more people, with most smart watches having an optical HRM built in. Optical HRM’s are great for monitoring sleep, and daily use but if you want to monitor heart rate in real time whilst running or cycling then a chest HRM is the way to go, these are much more accurate and generally show actual HR rather than jumps in HR that the Optical sensors can. 

The benefits of polarised training or low Heart rate training

Increased endurance, higher fat burning capability, reduced recovery time, limits the risk of injury, increased efficiency, increase aerobic capacity, go faster for longer, fewer GI issues, training to run at your HIM or IM distance pace. Many do not appreciate that the best way to improve VO2 is in fact a lot of Zone 2 work.

You may ask what are the downsides of low HR/zone 2 training? Well, apart from struggle with keeping the HR down there are very few, your max HR may reduce, but this is no bad thing, you still complete hard efforts to compliment the training.

So why not just run or cycle to feel? I have found that a comfortable run speed and even cycle speed was generally in the Zone 3 of a 5 heart rate zone – Zone 3 is neither a high/hard effort or an endurance based effort therefore its somewhere in between, working in this zone doesn’t make huge improvements, but does feel comfortable. A lower heart rate, around zone 2, aids endurance, this increases fat burning capabilities and less reliance on carbs for fueling, it builds aerobic base capabilities and allows you to be active for longer without “blowing up”. Working the top end of Zone 4 works the body hard and helps to increase speed endurance and improve your lactic threshold, this coupled with Zone 5 work can improve overall speed but should only be done for limited periods.

The 80/20 rule

If you want to improve to be faster or run longer then you need to improve the engine and your heart is where it starts, get the heart working in the right zone and reap the rewards, generally look at working in Zone 2 for at least 80% of the time then leave the hard work in Zone 4/5 for less than 20% - staying away from the comfortable Zone 3 when using a 5 zone HR model for all but race prep sessions if you race is performed at zone 3 (Ironman to 70.3 race prep sessions)

Keeping the majority of your runs and cycles under 75% max HR or around 85% of your threshold HR, depending on your overall endurance fitness, means you have to slow down on inclines to keep the HR in check. On days where you complete intervals or “efforts” these are generally minimal but are hard efforts above 85% max HR or higher than 95% of threshold for the duration of the interval with recovery back to lower HR - By working the majority of the training at a lower heart the body becomes better at burning fat for fuel as apposed to carbs, this means you can train longer without the necessity to fuel on carbs as much, however when the heart rate is elevated and in race situation the body will still require additional carbohydrates as fuel to maintain this. The ability to utilise Carbs is still important and should be trained within the correct sessions.


28 February 2026
Heart rate variability (HRV) has become one of the most useful metrics in endurance sport, but it’s especially valuable in triathlon. With three disciplines, frequent double sessions, and a constant balance between volume and recovery, triathletes face a more complex training load than single sport athletes. HRV offers a way to understand how your body is coping with that load before fatigue shows up in your pace or power. HRV looks at the tiny differences in timing between each heartbeat and reflects the balance between the sympathetic system (stress, intensity, activation) and the parasympathetic system (recovery, rest, adaptation). Higher HRV usually means your body is ready to take on stress; lower HRV suggests you may need to back off or adjust. Why HRV matters in triathlon training Triathlon training creates a unique mix of stressors. You’re not just dealing with mileage you’re dealing with different kinds of mileage. Swimming challenges breath control and upper body neuromuscular coordination. Cycling adds long hours of low impact load that can mask fatigue. Running brings the highest mechanical stress and the greatest risk of injury. HRV helps you see how all of this adds up with a single signal that reflects the total stress your body is under, not just what you felt in your last session. How HRV can help you tarin smarter 1. Planning Key Sessions When HRV is at or above your normal baseline, your body is primed and ready for the tasks ahead - These are the days to schedule: Harder sessions like threshold or VO₂ intervals Longer aerobic runs or endurance rides Technical sets that require more mental awareness You’re more likely to hit your targets and recover well afterward. 2. Avoiding overreaching Triathletes often push too far without realising, a downward HRV trend over several days can be an early sign of: Accumulated fatigue without enough recovery Poor sleep / nutrition or higher alcohol intake High life stress, home or work related Illness brewing in the background Too many hard sessions stacked back to back Knowing this early helps you adjust before performance dips, illness or injury risk rises. 3. Balancing the three disciplines One of the biggest advantages of HRV is how it helps you shift training without losing momentum. Low HRV but legs feel fine → Z2 training, with some tempo intervals Low HRV with heavy legs → Try easy bike session rather than run intervals High HRV → carry on as intended – bike or run intervals, higher intensity. This flexibility is what makes HRV guided training so effective for triathletes. What HRV looks like across the three disciplines Swim - Swim sessions often produce less mechanical fatigue, so HRV may stay stable or even rise. Technique work is ideal on lower HRV days. Cycling - Cycling allows for high volume with relatively low impact. It can be easy carry on with tempo work because it “feels fine,” that zone 3 work always feels good doesn’t it …. but if HRV is lowering, then it could be you are overdoing it. Running - Running has the biggest impact on HRV because of its mechanical and neuromuscular stress. Reduced HRV is a strong signal to lower run intensity or volume to avoid injury risk. What affects HRV in Triathletes Triathletes deal with several stressors that strongly influence HRV: Early morning training / late night training Heat stress from indoor cycling / treadmill running Travel to races, pool, gym etc High carbohydrate intake to fuel sessions Life stress, sleep quality, and hydration Alcohol and or energy drinks Understanding and monitoring these helps you interpret HRV changes more accurately. What affects you may be different to what affects somebody else, knowing this can give you the tools to perform well and avoid the risks that low HRV can bring. In Summary HRV can be a powerful tool in a triathlete’s toolbox – you can use it to assist in managing training load, avoiding burnout, limiting injury and ultimately giving you the race day you deserve. It doesn’t replace good coaching or smart planning, but it can add a layer of insight that helps you train harder on the right days and recover better on the others. A little knowledge can go a long way
by Dan Mason 19 February 2026
When triathletes talk about improving their bike leg, the conversation usually jumps straight to power numbers, aerodynamic upgrades, or the perfect bike fit. All important, of course—but there’s a quieter, simpler metric that can transform both your ride and your run: cadence. Cadence isn’t flashy, it won’t earn you compliments in transition, but if you understand how it works and how to train it, it becomes one of the most effective tools for racing smarter, riding stronger, and running better off the bike. What is cadence? Cadence is the number of pedal revolutions per minute (rpm). It’s the rhythm of your ride, the tempo your legs naturally fall into. Most cyclists hover somewhere between 70–90 rpm, with some outliers above and below. But triathletes aren’t just cyclists, they’re cyclists who still have to have the energy and ability to run well after the cycle leg That’s why cadence matters so much in triathlon. Why Cadence matters for Triathletes 1. It is the driver for how you and your muscles fatigue Different cadences stress your body in different ways: Low cadence (50–75 rpm): High torque, high muscular load, especially on the quads and glutes. Great for building strength, but it can leave your legs feeling heavy for the run. High cadence (90–100+ rpm): Lower muscular strain, higher cardiovascular demand. You save your legs, but your heart rate may rise along with energy consumption. Triathlon is all about managing fatigue throughout and having the energy to finish the run strong. The right cadence helps you spread the workload across your body in a way that preserves your legs for later. 2. It directly affects your bike to run transition Ask any triathlete about “Jelly legs”: the first kilometre of the run can feel like a different sport entirely. Cadence plays a surprisingly big role in how smooth or painful that transition becomes. A slightly higher, more consistent cadence on the bike helps: Reduce that “Jelly leg” sensation Improve neuromuscular readiness Make it easier to hit your target run pace quickly Think of it as priming your legs for the turnover they’ll need on the run. 3. It Helps You Control Power and Avoid Spikes Power is a product of torque and cadence. When cadence drops on a climb, into a headwind, or when fatigue sets in torque rises. That means: Higher muscular strain More “matches” burned Greater risk of blowing up late in the day or race Holding a steady cadence helps you hold steady power, which is the foundation of a well paced triathlon bike leg. 4. It Improves Long Distance Efficiency Efficiency isn’t just about aero helmets and deep section wheels. It’s also about metabolic cost. Research shows: Elite cyclists often prefer higher cadences to reduce muscular fatigue. Age group triathletes often default to lower cadences, which feel comfortable but accumulate fatigue over time. Training your body to handle a slightly higher cadence—without sending your heart rate through the roof—can make your entire race feel smoother and more sustainable. How to train cadence like a triathlete 1. Add cadence focused drills to your training - A few effective options: High cadence spinning: 100–120 rpm for short intervals – increases ability to spin when needed, such as on a climb with fatigued legs, on a decent when you have run out of gears Low cadence strength work: 50–70 rpm at moderate to high resistance – this aids strength training, increasing your torque and power – used when accelerating hard, grinding over that steep climb – ultimately building your cycling strength to hold higher watts. Cadence pyramids: gradually increasing and decreasing rpm – giving you great variety and switching ability from grinding to spinning. These drills improve neuromuscular coordination and expand your comfortable cadence range. Having a large range of cadence in your pocket is a game changer when it comes to competing in triathlon, giving you greater flexibility in body and in race plan and execution. 2. Use brick sessions to test your race cadence Your ideal cadence is the one that lets you run well afterward – (this is usually similar to your run cadence). Brick workouts are the most reliable way to discover what actually works for your body. 3. Treat cadence as a pacing anchor Conditions change on race day, wind, terrain, fatigue but cadence can be your stabiliser. If you keep cadence smooth and consistent, power tends to follow. So what’s the “best” cadence? There’s no universal magic number, but for most triathletes a steady 80–95 rpm during the bike leg strikes the right balance between muscular preservation and cardiovascular efficiency. The real goal isn’t hitting a specific number it’s finding a cadence that’s sustainable, efficient, and sets you up for a strong run. Cadence isn’t just a metric, it’s a strategy and when you use it intentionally, it becomes one of the most powerful tools in your triathlon toolkit.
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