Zone 2 Training: Unlocking the Key to Sustainable Fitness and Endurance
When it comes to any aerobic endeavour, whether running, rowing, swimming, cycling, triathlon etc you’ll always hear the term “build your aerobic base,” and for good reason, your success in an aerobic endeavour is going to largely be determined by how big your aerobic base is.
The term aerobic base is well-known, however, the training used to build it is often poorly executed due to training sessions being too hard, resulting in the person training in the wrong training zone and creating the wrong training stress.
When it comes to building your aerobic base, the training required is mainly going to be Zone 2 training.
Zone 2 is the most trainable zone when it comes to developing your aerobic system. It has the highest potential for long-term aerobic development, and it has the greatest impact on increasing your aerobic threshold. Simply put, if you want to take your aerobic capabilities to a higher level, Zone 2 training is where a large majority of your training should be focused.
But before we move on and dive into Zone 2 training more, you may be thinking “What on earth is a training Zone?” so let’s break down Zones 1-5.
Zone training, or heart rate zone training, is a way to monitor how hard your training effort is or should be, during a training session.
There are 5 heart rate training zones, each based upon a certain intensity percentage of your maximum heart rate.
Zone 1: 50-60% of your max heart rate
Zone 2: 60-70% of your max heart rate
Zone 3: 70-80% of your max heart rate
Zone 4: 80-90% of your max heart rate
Zone 5: 90-100% of your max heart rate
Each zone creates a different training stress, and therefore different training adaptations and outcomes, so you want to ensure you’re training in the right zone for the outcome you desire to increase your training performance.
When it comes to energy system training, it is divided into 2 focused areas, power, and capacity.
Power is the rate at which a specific energy system can produce energy.
Capacity is the duration capability of a specific energy system.
Both power and capacity are important when it comes to overall performance, however, when you train them matters. You want to ensure you increase your capacity for a specific energy system first, before increasing its power capabilities. Without higher levels of capacity, your power output will always be limited by your duration capabilities.
When it comes to developing your aerobic performance, and, specifically developing its capacity, Zone 2 work should be your primary focus.
What does Zone 2 training look like?
It’s low-moderate effort continuous aerobic training at ~60-70% of your max heart rate
It’s training performed below your cardiac output level, which for most people is below 150bpm, and that level will often decrease based on age and current aerobic abilities.
It’s low-stress training, both physically and mentally, so your ability to recover from it is much higher allowing for it to be trained more frequently each week and for longer weekly total durations.
An example of how Zone 2 is a lower-stress training method:
If you run 5km hard with an average heart rate of 165 bpm, this comes to as a higher training stress cost due to the intensity based upon your heart rate in comparison to your max heart rate, and the zone you’re training in.
However, if you run that same 5 km keeping your heart rate in Zone 2 [sub 150bpm], or 60-70% of your max heart rate, this comes at a much lower training stress cost allowing you to recover faster and therefore have greater potential to perform more of that type of training either per week or in a session.
What are the benefits of Zone 2 training?
Increased aerobic efficiency and economy: If you’re more efficient you can work harder at lower heart rates.
Increased aerobic capacity: You’re going to build that all-important aerobic base.
Increased Cardiac Output: This increases your heart’s ability to pump more blood per minute.
Increased Stroke Volume: This is a result of eccentric hypertrophy of the heart’s left ventricle. This results in more blood being pumped out of the heart per beat.
Decreased resting heart rate: This increases your aerobic heart rate range by “lowering the floor”.
Increase in Mitochondria density: Mitochondria are the aerobic power stations in each cell, more power stations allow you to train for longer or harder.
Increase in capillarization: This increases the blood flow to your working muscles.
Increased ability to recover during and between training sessions: as recovery happens in an aerobic state, the greater your aerobic capacity, the greater your recovery capacity.
Increase in slow twitch muscle fibres: Increased efficiency and aerobic qualities of your slow twitch enhance your aerobic performance.
All sounds awesome, right?
I know your next question.
What do I need to do in my training to get these incredible benefits?
Zone 2 Training Guidelines
To maximise Zone 2 benefits, you ideally want your chosen activity to be continuous, like running, cycling, swimming etc.
Each session should ideally be 60-180+ minutes, again, to maximise your benefits. Obviously, ability and time available will dictate duration. If you’re new to aerobic training, or your fitness level isn’t very high, start low and build up gradually. Don’t start with a 60-minute run if you’ve not run for years, start with 20-30 minutes, and ramp up over the coming weeks and months.
To gain maximum benefit from Zone 2 training you want to be completing between 2-4 hours per week. Depending on your current level of aerobic fitness, and your aerobic goal needs, this may dictate if you’re on the lower or upper end of this spectrum. Ideally, you want 60+ minutes of work to gain full benefit a couple of times a week, but 4x 30-minute sessions across 7 days will still see you hit the 2-hour total mark if that is what your current available time and ability allow.
If you have an aerobic goal, Zone 2 work should be your priority focus for at least the first 8 weeks of a training cycle before sprinkling in harder interval work later. You want to build your aerobic capacity as big as possible, and even when you do have the harder intervals in your training you don’t abandon Zone 2 work, you just lower the total duration accumulated each week.
Zone 2 training may sound simple and easy, I mean it is just continuous activity at a low-moderate effort, but for a lot of people, it can be a challenging transition from what they’re used to, especially if what they’re used to is running every single training session as hard or as fast as possible in the pursuit of faster times, further distances or just feeling tired or that they’ve “worked hard” in the training session.
Being focused, disciplined, and sticking to Zone 2 will allow you to run better, faster, and longer than ever before in the future. It doesn’t feel hard.
Keep it slow, low-moderate in effort and ensure that you’re accumulating close to 2-4 hours a week of Zone 2 training.
Zone 2 training will help you become an aerobic machine, not to mention, help with fat loss.
