Using a heart rate monitor and training to set Heart Rate (HR) zones brings great benefits if done correctly; however, it is very easy to make assumptions by following the common, misleading guidelines that are all around us.
In sports centres and gyms, you will no doubt have seen posters showing you how to calculate your HR zones based on the formula of 220 (or 180) minus your age. While this introduces a more scientific approach to training, it can be very unreliable to the point of being total gobbledygook. These days there are several non-specific training programmes out there in the ether that prescribe HR-based training with no knowledge of the individual they are catering for.
Like any tool, HR training is only useful if used properly.
Let’s clear up a few myths:
1. Age is irrelevant in determining training zones.
It used to be thought that your maximum HR declined with age, hence the ‘minus your age’ bit of the formula. This is a generalisation, as many older people who maintain active lifestyles can hold a very similar top-end HR to that which they had when they were younger.
‘220 minus your age’ doesn’t take into account the individual. We know a fit 56-year old with the same maximum heart rate as a 28-year old. If he was to use the 220 formula, he would be 28 beats lower throughout his training zones. Bearing in mind a specific training zone tends to cover around 8 to 12 beats; he would be training completely the wrong zones if he was to stick rigidly to the illogical numbers. Conversely, someone with a slow natural heart rate could end up killing themselves in every session just to stick in their ‘zone’.
2. HR zones are not sport-specific.
Anyone who has worn a heart rate monitor will have observed that HR is higher on the run than on the bike for the same perceived effort.
Training zones can easily vary by as much as ten beats for different sports. So HR zones which might work fine for the bike would most likely be too easy for run training. The 220/180 method does not take this simple fact into account.
3. Fat Burning Zone: Fat Chance!
Another trend with HR training comes the highly coveted ‘Fat Burning’ zone. Some gym users and even triathletes who have not done their homework believe that you must train easy to burn fat. You even see Personal Trainers making people stick within their mythical ‘fat burning zone’ in one-hour workouts; very misguided.
Fat Burning in terms of fuel production, for endurance athletes, is crucial, as we need to be able to access our fat stores when glycogen runs low. It is true: we do burn a higher percentage of fat at a lower intensity (great for us, teaching our bodies to access fat supplies), but the overall calorific burn is far less, meaning for weight loss, high intensity is still better as energy expenditure is through the roof compared with low intensity.
Weight loss will occur quickly if energy output is greater and nutrition is sensible. For endurance athletes, we want to become efficient at burning fat for fuel, but miles of easy training will not necessarily lead to weight loss; we’ll just become very efficient and actually limit energy expenditure. This is where people get their paths crossed. There is no such thing as a ‘fat burning zone’ when it comes purely to weight loss. Put another way, an hour of low-intensity training will not make you leaner than an hour of higher intensity training; to the contrary.
Of course, there are those who will find the standardised formula works fairly well for them. A bit like winning on the horses: it will work out for someone! If you are going to use science, then it is of course rational that you should do it properly. The best thing you can do is book in for a lab test for bike and run testing (it is possible to get swim tests done although this is trickier to organise for obvious reasons). Once you have your actual numbers, you or your coach can apply it to your training program with accuracy. Alternatively, ditch the arbitrary science and go on feel and perceived effort: you’ll get more benefit from that than you would following a set of randomly prescribed numbers.
Above all, make sure your training is helping you improve: if it is, then you are on the right track!