Start diving into the world of cycling and running training, and chances are you’ll quite quickly come across talk of ‘Zone 2 training’. But what the bleat does that actually mean, and can riding/running easy really help you to get faster and more efficient long term?
It might not be the flashiest or most exciting type of training. And it might not make it rain Strava kudos. But Zone 2 training is actually a very useful component of your weekly training schedule. Done correctly, it can help you to get stronger, become more efficient and build a base line of fitness that unlocks your potential to push the pace when it really counts. Sound good? Read on to find out what Zone 2 training is, what the benefits are and – most importantly – how to make sure you’re actually doing it.
Jump to…
- What are training zones?
- What are the benefits of training in Zone 2?
- How to stick to Zone 2 while cycling and running
What are training zones?
Training zones are a way to quantify different intensities of exercise. Each zone utilises a different energy system, and stimulates a different physiological response. Zone 1, for example, is very easy activity designed to promote ‘active recovery’. Meanwhile Zone 6 is the truly spicy stuff – think short, sharp intervals that make 30 seconds feel like 30 hours.
The zones you need to train in, and how that’s split across your training load will depend on A) what you’re training for, and B) your training history and current fitness level. An endurance cyclist or ultramarathoner is going to have a lot more steady base work compared to a 100m sprinter, for example. The exact paces or power you’ll need to work at to hit in each zone also varies hugely between individuals. But by giving a % of max heart rate (or threshold power) alongside a rating for perceived effort. Coaches and training plans can use zones to prescribe intensity levels, and you can dial this down to match your own physiology.
There are a few different training zone models out there, ranging from three zones to eight zones. But to keep things simple, below we’ve use the most common six-zone model.
Zone 1: Active recovery
- < 50-60% of maximum heart rate
- <55% of functional threshold power
- Perceived effort: 2/10
What it is: Zone 1 is what we call ‘active recovery’. Your heart rate will be elevated a little above base line, but you’re not putting in any real effort. Think a super easy spin, a brisk walk or a very easy jog.
Benefits: Zone 1 mainly helps to stimulate blood flow to your muscles. It can be useful as an early stage of your warm up. Or it can be part of your recovery strategy, helping to speed up the delivery of oxygen and muscular repair agents while also flushing away waste products to ease stiffness and sore muscles after a big training day.
Zone 2: Endurance
- 60-70% of maximum heart rate
- 55-75% of your functional threshold power
- Perceived effort: 4/10
What it is: Zone 2 training is your go all day, easy endurance pace. You’re working at an intensity above active recovery and your breathing rate will be slightly elevated, but you can still easily hold a conversation. Think easy long run, or casual cafe ride pace.
Benefits: We’ll take a deeper dive into the benefits of Zone 2 training and how it works later on, but for now Zone 2 training helps to make your cardiovascular system more efficient, improves your body’s capacity to use fat as a fuel source and improves lactate clearance. All of which essentially means that over time, you’ll be able to go faster for longer before fatigue sets in.
Zone 3: Tempo
- 70-80% of your maximum heart rate
- 75-90% of your functional threshold power
- Perceived effort: 6/10
What it is: Zone 3 is often the effort we’re working at when we think we’re in Zone 2. That’s because Zone 3 can feel pretty comfortable for a few hours, but also gives you that ‘I’m putting a bit of effort in’ feeling. Typically, Zone 3 would correlate to your marathon pace or hard effort long ride (>50 miles) pace.
Benefits: Too much Zone 3 training can put you in a bit of a hole, as it takes more out of you than you realise and leaves you without enough capacity to go hard enough when you’re supposed to be. But there are some benefits. Zone 3 is ideal for longer intervals, where the focus is on raising your first lactate threshold. At this intensity, your body can actually utilise lactate (the by-product created when your body burns carbohydrate for energy) as a fuel source and so some strategic training in Zone 3 gets your body super efficient at clearing lactate. In real terms, raising your first lactate threshold means things like your marathon race pace of longer time trial pace will get faster for the same perceived effort.
Zone 4: Sweet spot
- 85% of your maximum heart rate
- 90-95% of functional threshold power
- Perceived effort: 7/10
What it is: Sitting just below your 1hr threshold, Zone 4 is often referred to as sweet spot – quite literally because it sits in that ‘comfortably uncomfortable’ sweet spot.
Benefits: Sweet spot training raises your 2nd lactate threshold – the point at which lactate really starts to accumulate in the blood which translates to ‘feeling the burn’ and usually, having to slow down.
Zone 5: Threshold
- 85-95% of your maximum heart rate
- 95-105% of functional threshold power
- Perceived effort: 8/10
What it is: The very top end of your aerobic capacity (sometimes just above it). Essentially representing the maximum effort you’d be able to hold for 60 minutes (and doing so would feel rather spicy!)
Benefits: Best reserved for shorter intervals Zone 5 training helps to boost your top end speed by pushing it up from below. But the physiological adaptations also help to speed up your steady endurance paces. Sessions such as 6-8 x 3 mins with 1:30 easy rest in between work well for cycling and running. Threshold work can be quite demanding, so ensure you’ve got an easy day afterwards to recover and get the benefits.
Trainings terms explained: What is functional threshold power?
In cycling, the amount of power (the force you’re putting through the pedals to create forward momentum) is measured in watts. Functional Threshold Power (FTP) refers to the maximum amount of power that a rider can put out for 60 minutes. It’s an indicator of where your current bike fitness is. We’ll guide you through how to find your FTP later on in this article, so keep reading!
Zone 6: VO2 max
- > 95% of your maximum heart rate
- > 105% of functional threshold power
- Perceived effort: 9/10
What it is: Welcome to the pain cave! Zone 6 is your VO2 max, representing the maximum effort you can sustain for between 40s and 2 minutes. Zone 6 work is well… horrible, basically. Let’s call it ‘Type A’ fun – the endorphins are awesome once the session is done but be prepared to feel the burn during.
Benefits: VO2 max work raises the ceiling on your performance. The higher your VO2 max, the more ‘room’ there is to raise your threshold, and in turn all of your race paces. It’s also great for building up that ability to grit your teeth and dig deep that you’ll want to call on at the end of a race. Be warned that it’s tough going, and you’ll want a decent warm up and plenty of recovery afterwards – use Zone 6 training sparingly!
Training terms explained: What is VO2 max?
VO2 max is the maximum amount of oxygen your body is able to take up and utilise. It’s essentially a physiological indication of your performance potential. World class athletes will naturally have a high VO2 max before they even start training. Targeted interval work can raise your VO2 max, but we all tend to have a physiological ceiling. Think of threshold power and pace as an indicator of your current fitness and performance level, and VO2 max as the ceiling of your potential.
What are the benefits of Zone 2 training?
So that’s what Zone 2 training is. But what are the potential benefits, and why should you do it? It can feel boring, and you might even think it’s a waste of time. But getting the right balance of higher intensity work alongside Zone 2 training can actually be a bit of a secret weapon to unlock improved speed and endurance. Here’s why:
Develops aerobic fitness
Zone 2 training develops your aerobic fitness. It strengthens your heart muscle, which in turn increases your stroke volume (the amount of blood pumped around the body with each heart beat) and the amount of oxygen that can be delivered around the body. As the body adapts, more capillaries are formed and this in turn helps to make your muscles more capable and efficient at converting fuel (such as glycogen) into energy in the presence of oxygen.
Improves endurance
Performing more of your training in Zone 2 also helps to develop your endurance. This type of training primarily works your Type 1 (slow twitch) muscle fibres, and makes them more efficient at removing waste products (i.e. lactate) which are responsible for that horrible burning lungs, jelly-legged feeling you get after a strong effort, both using lactate as a fuel source and clearing it more efficiently through improved blood flow. The physiological adaptations created by Zone 2 training mean that as time goes on you’ll raise your first lactate threshold. In simple terms, this means you’ll be able to go faster, for longer, with less fatigue.
Improves fat oxidisation
Zone 2 work gives your body the opportunity to be more efficient at using fat as a fuel source, known as fat oxidisation. This is useful because it means your glycogen stores (i.e. carbohydrate) which are a finite resource, can be reserved for harder efforts. And using fat as an energy source delays the accumulation of lactate. When the body burns carbohydrate, lactate is produced as a by-product along with acidic hydrogen ions, which bind together to form an ‘acid’. This creates the burning sensation that forces you to slow down. Once again, Zone 2 training is waving a bit of a magic wand to enable you to go faster for longer before fatigue kicks in!
How to stick to Zone 2 training while cycling and running
A lot of us tend to think we’re in Zone 2, when we’re actually creeping up into Zone 3. That “easy spin” on Strava? Hands up if you’ve been guilty of calling it that when it wasn’t quite as easy as you’d like to let on. Guilty as charged! If you’re new to really trying to be disciplined with your Zone 2 training, it might feel way too easy to begin with and you might have to slow down significantly to stay within the zone. Try not to worry too much about your pace or power, and leave that Strava-fear at home. Over time, your body will adapt and you’ll be able to go faster for less effort.
Being able to actually stick to Zone 2 often means gathering a bit of data, knowing exactly what intensity level you need to be working at – and staying disciplined. This is where knowing your maximum heart rate, threshold running pace and/or functional threshold cycling power comes in. Once you have this data, you can then work out exactly what heart rate you should be working at, the power you should be pushing or the pace you should be running to be within each training zone – see the percentages above!
How to find your maximum heart rate
The old adage used to be to subtract your age from 220 to find your maximum heart rate. For example a 40 year old would therefore have a max heart rate of 180. However this method doesn’t factor in things like fitness levels, gender and genetics which all have an impact on what your individual max heart rate is. It gives you a ball park figure, but it’s not particularly accurate. The Athlete Training Blog provides some alternative formulae which may be more accurate:
“[207 – 0.7 x Age ] – more precise formula, adjusted for people over the age of 40
[211 – 0.64 x Age ] – slightly more precise formula, adjusted for generally active people
Unfortunately, neither of above-mentioned formulas are gender-adjusted. Generally women tend to have a 5-to-10-beat higher maximum HR than men, so that is additional something to account for.”
Plenty of fitness tracking devices these days will actually be able to tell you your maximum heart rate based on your activities if you’ve consistently been training wearing a heart rate monitor. Alternatively, you can get a measure of your threshold heart rate by completing a 30 minute race effort and taking an average of your heart rate during the last 20 minutes. Joe Friel (an endurance sports coach well-known for being the author of ‘The Triathlete’s Training Bible’) gives an explanation of this in his quick guide to zone setting for Training Peaks.
How to calculate your cycling Functional Threshold Power (FTP)
There are two ways to get your cycling FTP. The first is to go and do an all-out 60 minute effort where you finish feeling like you’ve left every single drop of blood, sweat tears and goat-knows what else out there. The second, which is only slightly less horrendous-sounding is to do an FTP test. There are two types of FTP test: the first is a 20 minute effort. Tick off a warm up and then buckle up and push as much power as you can for 20 minutes. Take your average power output and multiply it by 0.95 and you’ve got your FTP. The second FTP test method is a ramp test. Typically, you’ll increase your power in 1 minute increments until you’re toast and you need to quit. You then take 75% of your max 1 minute power to get your FTP.
Platforms like Zwift and Rouvy have dedicated FTP test workouts you can do, which takes the maths out of the equation.
Don’t rely solely on one type of data
Keep in mind that what might be an easy pace or power one day, can be a bit too hard the next depending on your fatigue levels and how well you’ve recovered. For Zone 2 training, it’s useful to use your pace/power threshold in tandem with your heart rate to make sure you’re working at the right intensity on any given day. Heart rate is usually a good indicator of where your part is at right there and then, so if you notice your heart rate is creeping up way beyond the ceiling for Zone 2, even if you’re pushing Zone 2 watts – that’s your body’s way of saying it’s tired and you need to go easier.
Trust the process, and leave your ego back home
Once you have the data to know what you should be doing to stick to Zone 2 for your easy endurance rides and runs. It comes down to trusting the process. If you’re new to Zone 2 training, it might feel slow, and it’ll probably be a little bit boring. It won’t look wildly impressive on Strava. But you’ve just got to let that go. Stick to your guns, and trust that after a few weeks your Zone 2 pace/power will naturally start to improve. Soon you’ll be going faster, for less effort. And when it’s time to really unleash the beast and race hard, get ready to be buried in Strava kudos as you rack up the personal bests!