Once you start diving deeper into the world of running training, it’s likely you’ll start to come across folks talking about training zones. From that person you follow on Strava who always titles their max efforts as an ‘easy Zone 2 run’, hoping no one notices their suspiciously through the roof heart rate. To workout descriptions on run training plans. Training zones are a way to quantify different effort levels. They’re essentially a simple way for you to gauge how hard or easy you should be going in any given run workout. And to structure your overall training plan to ensure you will create the appropriate adaptations to meet your running goals. Endurance runners often see Zone 2 running as the holy grail for improving their aerobic fitness and efficiency, allowing them to run further and faster.
Knowing what each training zone means and the fitness adaptations they can stimulate can help you to get really specific and time efficient with your run training. To help you get in the zone, we take a look at what training zones are in running, the benefits to be gained from worked in each zone. And how to make sure you’re actually training in the zone you intend to be.
What are training zones?
Training zones describe set levels of exertion/effort when you’re exercising. In running, we express training zones using heart rate, pace and perceived exertion ranges. Each zone works a slightly different energy system, stimulating different training adaptations. For example, Zone 2 running will build aerobic endurance. Whereas Zone 6 efforts will be about developing top end sprint speed. Track runners are likely to spend more time focusing on training in the upper zones, compared to marathon runners who are likely to perform the bulk of their training in the lower zones to build endurance.
Different coaching methods can take a slightly varied approach to training zones. You might come across people using a five zone method, or even a seven zone method. But for the purposes of this article, we’ll be referring to the most widely used six zone method for dialling in your run training.
Training zones explained
Understanding what each training zone means and how to manage your effort to stay within the prescribed zone will help you to make sure you’re getting the full, intended effect of every run workout. Getting to grips with training zones is also useful if you’re self-coached, so you can take a look at your overall training schedule to make sure you’re balancing any high intensity work with recovery and steady efforts to maximise your gains, without risking injury/burn out.
Keep reading to learn more about each run training zone and the benefits they bring. Including what zone 2 running is, and how to do it properly.
Zone 1
Zone 1 is an active recovery training zone. The perceived effort is easy, and your heart rate is slightly elevated from base line, but not so much that you’re out of breath. Depending on your fitness levels, this might be a very easy jog or even a brisk walk.
BENEFITS OF ZONE 1 RUN TRAINING
Zone 1 running is primarily about gently stimulating blood flow around the body. It can be beneficial at the start of a run to begin warming up the muscles and joints before harder efforts. Zone 1 running can also be used as part of your recovery strategy to help repair sore muscles by increasing blood flow, which in turn speeds up the delivery of oxygen and repair agents and the removal of waste products. If you’re struggling with delayed onset muscle soreness (DOMs), a gentle Z1 active recovery jog can help to ease muscle soreness and stiffness.
Zone 2 running
Zone 2 run training isn’t flashy or impressive. In fact, it can be kind of boring – and it takes discipline to leave your ego at home, ignore the lure of the Strava segments and slow the heck down.
But done properly, Zone 2 running can set you up with an incredibly strong foundation of aerobic fitness that will allow you to unlock your potential for those faster race-pace efforts. Zone 2 running is your easy endurance pace. You’re putting in a bit of effort to elevate the heart rate above active recovery, but your breathing rate isn’t significantly elevated and you can easily hold a conversation.
When you’re running in Zone 2, you should have that near-effortless “I could do this all day” feeling. It’s really important to use objective data – ideally heart rate – when you’re trying to stick to Zone 2 to make sure you’re physiologically working the right energy zone. Most of us think we’re going easy and staying in Zone 2, when in reality we’re creeping up into Zone 3.
BENEFITS OF ZONE 2 TRAINING
For all runners, Zone 2 training has a significant place in your training regime. But particularly if you’re looking to improve your marathon time or half marathon time, Zone 2 running needs to be a key part of your training schedule. And here’s why.
Running in Zone 2 helps to develop your aerobic fitness by improving your cardiovascular efficiency. Working the aerobic energy system at a lower intensity enables the body to become more efficient at delivering oxygen to the muscles, and utilising that oxygen to create energy. The body also gets better at clearing lactate by using it as a fuel source. This will raise your first lactate threshold, and enable you to go faster for longer before the onset of fatigue – key for long distance runners.
Zone 2 running also helps the body to improve fat oxidisation. The better your body is at using fat as a fuel, the less you’ll have to rely on carbohydrate to produce energy.
EXPERT INSIGHT
“Having a good fat oxidation will allow you to rely on fats to provide a large proportion of your energy requirements rather than using the finite glycogen stores which ideally should be conserved for periods of higher intensity or later in an event.”
Lucija Petrovic, expert physiologist at Loughborough University Performance Lab
This is useful for endurance runners because when we burn carbohydrates, we also produce lactate. After a certain amount of time the body can no longer clear lactate quickly enough, so it begins to accumulate in the bloody. As we produce lactate, we also produce hydrogen ions which together form an acid, and create the burning fatigued sensation in the muscles which cause you to eventually slow down or stop. If you can train your body to utilise fat as its primary fuel source for longer, at higher intensities, you’ll delay the accumulation of lactate and the associated sensation of fatigue. Being able to utilise fat more effectively also reduces the overall amount of carbohydrate you have to take on during a race, which is ideal if you struggle to stomach a lot of energy gels.
WHY ZONE 2 TRAINING ISN’T A WASTE OF TIME
We can often fall into the trap of thinking that if we want to be able to run faster over longer distances, we’ve simply got to go faster in all of our training sessions. And while that might work to boost your fitness in the short term, it’s not sustainable. Over-reaching in training is a recipe for injury and burnout long term.
Training ‘easy’ in Zone 2, even if it means leaving your ego at home and embracing a bit of boredom, will stimulate the correct energy systems to facilitate being able to push harder and run faster when it counts. Which is why it should make up a significant portion of your weekly training hours if you’re a longer distance runner. But not all of them. Of course, if you only ever train at Zone 2 – you’re just going to get really good at going at a steady pace for a long time. If getting faster is the aim, you need to complement your Zone 2 training with higher intensity run sessions that are going to ensure you’ve got some top end fire power when you need it.
HOW TO STAY IN ZONE 2 WHILE RUNNING
Many runners struggle to stay in Zone 2. The reality is it takes discipline, and accepting that your average pace is going to have to drop – at least at first. Use a running pace calculator such as the V.Dot calculator. Enter a recent time from a 5km or a 10km race effort, and then take a look at the calculated training paces. The top end of the ‘easy’ pace is the maximum you should be running at for Zone 2 training.
Wear a heart rate monitor to give yourself objective data too – it will keep you honest. It’s easy to kid ourselves we’re going easy when really we’re pushing on a touch too much. Using heart rate takes into account how you’re feeling on a given day. Variables such as your stress levels, fatigue and recovery status, alongside ambient temperature and the terrain your running on will all impact how ‘easy’ a given pace actually is on your body. To find your Zone 2 running heart rate, look at the max bpm you hit during a recent 5km race. Then complete the following calculation: 0.7 x [max HR].
Actually sticking to Zone 2 will mean that you’re not putting unnecessary fatigue into your body, so you’ve got the energy to go hard in your higher intensity sessions. Many of us do our easy sessions too hard, and our hard sessions not hard enough. Get the balance right, and you’ll soon see big fitness gains. Over time, your Zone 2 pace will naturally increase as your aerobic fitness improves. Slow down, to speed up!
Zone 3
Zone 3 is often the zone we creep into when we think we’re doing Zone 2. That’s because the intensity feels manageable enough to hold for longer run, but hard enough that we also ‘feel’ like we’re pushing and gaining fitness. It ticks the box of ‘Well I feel like I’m pushing myself so this must be beneficial’, whereas many people find Zone 2 feels too easy and struggle to trust that it’s helping them to build fitness. If the last few miles of your ‘easy Zone 2’ long runs always feel like a drag, chances are you’re probably working in Zone 3.
Zone 3 is where we typically hit our first lactate threshold – the point where blood lactate levels rise above the base line. At this intensity, the body can clear the lactate effectively by using it as fuel which enables us to maintain the effort for a few hours – though towards the end it will start to get hard to hold the pace. In terms of racing, Zone 3 would be your marathon race pace.
BENEFITS OF ZONE 3 TRAINING
Zone 3 run training is beneficial when executed deliberately. It’s ideal for interval sessions with longer efforts (such as 3 x 15 minutes) where the aim is raise your first lactate threshold (LT1). Improving LT1 means your endurance/marathon pace will become faster, for the same perceived effort.
But doing too much of what should really be Zone 2 running at Zone 3 intensity (i.e. going too fast on your long, slow endurance runs) is where you can start to cause issues. At first, you’ll probably see a boost in fitness. But over time, the additional fatigue you’re putting into your body will impact your recovery, and you won’t get all the base-building aerobic adaptations that Zone 2 running brings. After a while, you won’t have the energy to execute your high intensity sessions properly. And you could even end up having to take time off with injury or burn out. Too much Zone 3 training can end up being a waste of time if it sets you back.
Zone 4
Zone 4 running is that sweet spot of ‘comfortably uncomfortable’. You’re working hard and pushing on, but you’re never having to go full gas, and you still feel in control of the effort.
Depending on your fitness levels, you could probably run at Zone 4 effort for a total of 40-60 minutes – but it would start to feel quite tough towards the end if you did it as one sustained effort. For most runners, Zone 4 would be their 10km race pace/effort.
BENEFITS OF ZONE 4 TRAINING
Zone 4 training is a good way to raise your second lactate threshold (LT2). For most runners, we see that second jump in blood lactate levels when they get around their 10km pace. Pushing your LT2 up with medium-length Zone 4 intervals (reps of 8-10 minutes) will help you to be able to run faster before lactate accumulates enough that it forces you to slow down.
Zone 4 work is useful for runners training for half marathons and marathons because you’ll get the benefits and endorphin boost of a hard session. But it’s not so tough that you’re going to need days to recover from the effort. Ideal when you’re having to fit in higher mileage each week and recover quickly between sessions.
Zone 5
Zone 5 is your threshold zone, meaning you’re operating at limit of your aerobic capacity and at the top end of the zone, just above it. Interval efforts in Zone 5 will feel quite tough, particularly as you get towards the end of the session. And as a sustained pace, Zone 5 is closest to your 5km all-out race pace. You’d have to really push yourself to maintain it all the way to the end, and you certainly wouldn’t be able to hold on much longer.
BENEFITS OF ZONE 5 TRAINING
Zone 5 is for shorter intervals, such as 3-5 minute repeats adding up to a total of no more than 25-30 minutes within your training session. Typically you’ll be above your second lactate threshold (LT2) working at this intensity. Zone 5 interval work will help to improve your 5km pace – and the adaptations have the knock on effect of elevating your longer, steady endurance pace too.
Zone 6
Zone 6 is where you’re really going to feel the burn. Think shorter track repeats at a maximum effort that you can sustain for 1-2 minutes max (with good fitness levels). Run workouts with Zone 6 efforts are the ones you’ll love to hate. Hate them before and during, love the endorphin hit once they’re done. Just don’t do them too often, and make sure you do a full warm up before hand to avoid injuries. It’s also important to plan in an easier day afterwards so you have chance to recover and adapt.
BENEFITS OF ZONE 6 TRAINING
Zone 6 training aims to boost your VO2 max, which gives you more of a ceiling to improve your thresholds and speed up your race paces.
WHAT IS vo2 max? expert insight
“VO2 max is the maximum volume of oxygen that you are able to take up and use. This can be used as an indicator of endurance performance potential, although the lactate thresholds are more relevant predictors of your current performance capacity.” – Lucija Petrovic, Physiologist
VO2 max work gives you greater performance capacity from a physiological stand point. But these sessions are also a useful tool for building mental toughness and tenacity. You’ll have to get used to pushing through discomfort and tackling sessions that might look scary on paper. That experience will be valuable on race day, because you’ll have unlocked a greater ability to keep pushing when the going gets tough.
Quick re-cap/FAQs
Training zones are a way to quantify effort/intensity. They are based on data including heart rate, pace and perceived effort. Different training zones will deliver different fitness adaptations.
Zone 2 running is easy running at no higher than a 4/10 effort, 70% of max heart rate/threshold pace. It stimulates adaptations that improve your aerobic fitness, efficiency and ability to burn fat as a fuel source – all of which improves your running endurance.
Use a recent 5km race effort to calculate your threshold pace (using a pace calculator such as V.Dot) and max heart rate. Wear a GPS running watch and a heart rate monitor and ensure you are not going above 70% (max) of these values. At first, you might need to use a run-walk strategy to stay in Zone 2. As your aerobic fitness improves, you’ll be able to run faster and stay within Zone 2.
Lactate is produced when the body uses carbohydrate as a primary fuel source. At certain intensities the body can clear lactate faster than it is being produced, and actually use it for energy. But above these intensities, your body can’t clear lactate fast enough – known as reaching your lactate threshold. When lactate accumulates in the blood, the hydrogen ions produced as a by-product cause that acidic ‘burning’ sensation in your muscles that ultimate forces you to slow down or stop running.
VO2 max refers to the maximum amount of oxygen your body can uptake and use during exercise. The higher your VO2 max, the better your aerobic fitness. VO2 max can be limited by genetics, but high intensity interval training alongside aerobic endurance training can help to improve it – giving you more capacity to improve your race paces.
