Training Zones Explained

There are numerous discussions on how many training zones there are but at Foot Traffic we mainly refer to 5 zones. This article explains the Zones we use.

Throughout our Foot Traffic training programmes we often refer to a certain Zone you should be training in.  Whilst this may seem confusing initially, it is actually pretty straight forward and an extremely important component of the training and one which gives you some understanding of the purpose of each session.

There are numerous discussions on how many training zones there are but at Foot Traffic we mainly refer to 5 zones:

Zone 1: This is a super easy effort.  If you were to think of it in “rate of perceived exertion (RPE)” terms, it would be somewhere around 2-3/10 (1 being sitting on the couch, 10 being the hardest amount of effort - refer to the RPE table below). You may feel this pace is a bit on the easy side, but it is these sessions that help to develop your muscular endurance and form the necessary transition between key sessions. I like to think of these as recovery sessions. Nick Willis (NZ Olympic 1500m, 5000m runner) mentioned in an interview that on his easy runs he is often passed by older ladies out jogging. That is how easy you should be going. For swimming this zone is associated with technique and drills. For cycling and running if you are working off heart rate then keep below 70% of your threshold heart rate (THR) (remember your threshold heart rate is likely different for cycling and running). If you are working off power then keep below 55% of functional threshold power (FTP).

Zone 2: This effort should feel pretty easy as well, at least in the beginning of the session.  In RPE terms it should feel in the vicinity of 4-5/10.  You may even see cardiac drift towards the end of this workout.  (Cardiac drift is where your Heart Rate naturally begins to rise as a result of the duration of the exercise and possibly environmental factors such as heat.)  You should be able to hold a conversation for the duration of this workout.  When running hills, keep relaxed and your stride short. Pull the intensity back if necessary to make sure your heart rate doesn’t climb with you.  After some weeks training well in this zone you will become fitter and more efficient. You will be able to run faster while staying at the same heart rate.  If you have Data+ you will see your EF (Efficiency Factor) on TrainingPeaks increasing and this is a good way to monitor your progress. Spending too much time above Zone 2 in a training session, results in a Zone 3 workout. For swimming, aim for your 100m pace +10 sec. Heart rate when cycling or running should be between 70 and 85% THR and cycling power between 55 and 75% FTP.

Zone 3: Endurance Sport athletes don’t spend much time in this zone. It is a danger zone, in that too much time in this zone can lead to accumulated fatigue and muscle stress with limited training benefits. Time spent in this zone should be restricted to only what your coach has prescribed. It is kind of the middle ground between aerobic workouts and race paced efforts. This is an effort of about 6-7/10 on the RPE scale. It’s a pace at which you can talk but only speaking one-to-two words. This is somewhere between your Half Marathon and Marathon, or Half Ironman and Ironman intensity. Swim at your 100m pace +5sec. Heart rate is between 85% and 95% THR and cycling power keep between 75% and 90% FTP.

Zone 4: This is your Threshold zone, the RPE here is 8-9/10.  Working in this zone will result in burning legs and lungs sensation as lactate begins to accumulate. You wouldn’t be able to keep this effort up for much more than an hour. In training you certainly don’t spend long periods in this zone, but you may visit it a few times throughout a session, referred to in training programs as “intervals” and these come with adequate rest periods between them.  You would have to be pretty fit and race conditioned to spend a lot of time in this zone.  Some of you may never do a Zone 4 workout depending on what sort of event you are training for, your level of fitness and “training age”/experience in the sport. When training in this zone embrace the burn. The longer you spend in this zone the better your body gets at using any lactate it produces. For swimming, this zone is your 100m pace. Keep heart rate between 95 and 105% of THR and power between 90-105% of FTP. 

Zone 5 and higher are for shorter efforts and RPE for these are 9-10/10.  These efforts last from a few seconds to maybe five or six minutes. This zone is beneficial if you are doing a lot of racing that has hard but very short efforts, such as bike racing or racing shorter track running events. Swimming pace is 100m pace – 5sec, heart rate is >105% THR and power >105% FTP. 

For the average endurance athlete, the percentage of time you should spend training in each zone is roughly as follows:

For the average endurance athlete, the percentage of time you should spend training in each zone is roughly as follows:

Zone 1 and 2: 80-85%

Zone 3: possibly 15-20% if you are training for Half Marathon or Half Ironman, and will depend on what phase of training you are in.

Zone 4: 10-15%

Zone 5: 2-5%

You will notice that the majority of your time will be spent in the easy Zones 1 and 2. Injury and fatigue accumulate rapidly when you spend too much time training in the higher zones. However brief stints in Zone 5 can actually be beneficial for pushing your base fitness levels higher so you may find your program suggests doing a few very short and sharp efforts.  

If you are struggling to keep your heart rate under Zone 2, then you need to slow down. If that means you have to run for three minutes and walk for two minutes to keep your HR down then, by all means, do it. Sometimes I have told athletes to walk hills or slow jog headwind sections to prevent their heart rate from climbing too high. If you are a fit athlete getting back into training, try running without a heart rate monitor for two weeks, just so you aren’t bothered by the seemingly high heart rate that you are operating at. Put it back on once you have a sense of fitness coming back. You may feel that training in Zone 2 and under is a step back but you will see the progress over time and you will be thankful you were patient during this important phase.

Zones 1 and 2 help you to develop muscular endurance, allowing you to train for longer durations and recover quicker. In addition, these easy training sessions help build capillary pathways that transport oxygen to your muscles and carry waste bi-products away from your muscles. The more capillary pathways that you can build, the more efficient you will be. Efficiency is equal to free speed.

Long slow training has actually been shown to develop your fast twitch muscles (speed muscles) as well because these fibres start to get recruited in the last quarter of the session when your slow twitch (endurance) muscle fibres begin to fatigue.

Here’s a rule of thumb:  If it feels too fast, then it probably is.  What’s the hurry?  Sit back and enjoy the scenery. There will be plenty of time to go faster as you get closer to race day.

Threshold Heart Rate and Functional Threshold Power

Rating of Perceived Exertion (RPE)

The RPE scale is a simple method used to measure the intensity of your activity to enable you to quantify how you are feeling. The scale runs from 0 – 10 and the numbers relate to phrases used to rate how easy or difficult you find an activity.  Every athlete should be able to pick what score they are at out of 10 while they are training and racing.