Your exercising heart rate is your rev counter that shows how hard your body is working. It enables us to train at specific intensities with the aim of achieving targeted results across the spectrum from weight-loss and general endurance, to high-intensity fitness for racing.
To do this successfully, we need a sufficiently accurate measurement of your maximum heart rate (MHR), from which the values for the range of training zones are obtained.
Using the commonly-cited age-based method for determining your MHR (220-age) is no good as this is a very rough average and there is a very large variation around this value. This can lead to the training intensities being set way too easy or way too hard.
So, rather measure your MHR with a direct test.
Traditionally, this is done by doing a ramp test, which involves riding progressively harder at a fixed incremental rate, until you cannot do any more. You can use a smart trainer and any of the training applications that have a ramp test. Alternatively, you can visit a training and testing facility such as Bike2Max.
A maybe more practical way of measuring your MHR, is to head to a fairly substantial climb and ride for 5 minutes at a steady, very hard (but sustainable) effort, and then finish that with a 30-40 second maximal-effort sprint. The resultant MHR rate value will be as close as dammit to your true MHR, and can be safely used as your MHR to determine the different HR training zones.
From there it’s a fairly straightforward matter of setting your training zones, according to one of the conventional systems, in this case a 5–zone system.
Zone 1 - Recovery: up to 60%
Zone 2 - Endurance 1: 61-74 %
Zone 3 - Endurance 2 (a.k.a tempo or sweetspot): 75 -85%
Zone 4 - Threshold: 86-92%
Zone 5 - Maximal aerobic capacity: 90-95 %
In brief, zones 2 and 3 improve exactly what their title implies, ie your endurance. Training in zone 2 is done as a continuous-effort riding for up to several hours, depending on your level and the event you are training for. Training in zone 3 is done as intermittent or interval training of efforts of 15-60 minutes, for a total of up to several hours, again depending on your competitive level and demands of your goal events.
Training in zone 4, the threshold zone, markedly increases your threshold speed or power. This is perhaps better expressed as average race-pace, and is typically done in efforts of 4-20minutes, for a total of 40-60 minutes in this zone. Training in zone 5 markedly increases maximal oxygen uptake and thus maximal power output, which increases short-duration high power and speed. Training efforts are typically 1-4 minutes long, with a wide variation in the intensity as measured by power output, but with fairly similar MHR in the efforts themselves.
The exact mix of which efforts to do depends on a multitude of factors, mainly your current fitness, lifelong training history, performance or fitness goals, nature of and time to the goal event(s), daily available or preferred training time, age, body composition, and more.
Research of the past few years has shown that while there are several training systems to reach similar results in terms of fitness gains, doing shorter, harder zone 5 and zone 6 efforts (and lots of them), tends to produce faster gains than the more conventional longer efforts in zone 4.
This is the polarised training model, which in broad strokes limits the time spent in zones 3 and 4, and spends more time in zone 2 for the endurance conditioning, and in zones 5 (and 6) for the high-intensity training.
The finer details of the polarised training model remains a very active area of research, and is credited with the increased capacity for a more attacking style of riding in the elite riders. In the more recreational riders (ie anyone not riding for a salary) the increases in performance come not so much from a magical benefit of these efforts themselves, but simply from doing more high-intensity training than previously, when the focus was on mid-range zone 3 training and the familiar hills at zone 4.
*It's an important distinction to make that this is not to say that training in zones 3 and 4 is a bad approach, just that a shift in emphasis to more time in the top 2 zones is usually superior.
It's of course a bit more nuanced than this, and the short answer to how should I train is always aah, it depends, but it’s still a safe generalisation than any rider will benefit from more training in zones 5 and 6, and less training in zone 3 and zone 4.
It is a limitation of hr-based training that the exact intensity of the z6 anaerobic ( sprint) training cannot be expressed or set in hr terms, which is where training to power output really improves the quality and effectiveness of your training.
Nicole Craddock Physiotherapy is proud to be affiliated with Ian Rodger from Bike2Max. Thanks Ian for a very insightful blog.