https://www.cyclingweekly.com/fitness/training/training-zones-what-are-they-and-why-do-they-matter-180110
Grand Tour riders know exactly what their power output should be, to the exact watt, at any given moment. Cycling training zones can be used to ensure training sessions are completed correctly, and can also be used in races.
This focus on precision has trickled down to amateur level – with riders using heart rate monitors as well as power meters to reach the desired output.
>>> How to ride with a power meter
Training zones are used to give an athlete a set intensity at which they should be working to during an activity. They may, for example, be completing intervals at ‘zone three’ for 20 minutes.
Training using zones is important becasue it means that riders can be sure they’re pushing hard enough during intervals, that they’re racing at a sustainable output for the duration required, and that they’re pedalling gently enough on recovery and endurance rides.
Knowing what heart rate or power training zone to use in a time trial helps you produce a sustainable effort
The heart rate and power band for one athlete’s ‘zone three’ will be different to the values given to another rider – so before attempting to train using zones, you’ll need to carry out a test to gain either your max heart rate value or ‘FTP’ power (what you can produce for an hour). These values will be used to set your zones.
You can establish training zones in a number of ways, whether by riding hard for five-minute intervals before easing off to an easy 10-minute interval, all the way up to blood lactate analysis and planning your training around the thresholds that were found in a lab. However, the two most common measures used for cycling training are heart rate and functional threshold power.
Find your max heart rate to set your cycling training zones
Setting your training zones is based on finding out your maximum heart rate is and, from that, working out the zones. A popular method for finding your maximum heart rate has been to use simple equations, such as 214 minus (0.8 x age) for men or 209 minus (0.9 x age) for women, and the original 220 minus age. However, these methods are not very accurate; recent research and coaching techniques has suggested that this method is very outdated and shouldn’t be relied on.
To ascertain your maximum heart rate accurately, you’ll need to carry out a tough test. Ride four times at maximal effort to failure up a long, steady climb, the idea being that you will hit your maximum heart rate on one of the latter of the four ascents. Once you have found it, you can calculate the percentages from the training zone table accordingly.
