Hi Reader,

I'm not one to shy away from more contemporary thinking. I previously wrote about the overuse of electrolytes and whether we need to supplement with them, as much as the marketing departments would have us think.

Another area I believe can be overhyped is training using heart rate (HR). I am open in my coaching that HR is not a metric I use. But why would I not use this, and what alternatives do you have? As with most things I deal with, it's based on science, not following the herd, and ensuring your training is optimised for you and not the general population.

Why not HR?

From experience, training using HR can be less accurate than other alternatives, such as pace, feel (RPE), and even better, running power. What can affect your HR, leading to inaccurate values and potentially impacting your training?

Fatigue

Both a lack of sleep and overall fatigue from your training will lead to an elevation in your HR, by up to 5-10 beats per minute (BPM). Whilst not looking like a big impact, coupled with the other areas below, you are potentially training at a pace that is below what you are targeting for that session and, you could be going too easy for that interval or hill rep.

Stress

Stress is the scourge of modern society. Stress has a similar effect on HR, as lack of sleep. Studies have shown that workplace-related stress can raise your HR by 4-6 BPM. Again, not a massive amount and think how it is going impact that after-work run, when you are trying to destress, yet your HR is much higher.

Caffeine

I love my coffee, and we know caffeine is one of the very few proven and legal performance enhancers. But training with HR, that double espresso is going to give your HR a kick, and we know the effects can last for up to 24 hours post-ingestion. This can be a double-edged sword if training by HR, yep you get the boost you want but you are going to be running at a slower pace due to the impact of caffeine and trying to stay in the right zone.

Weather

A big factor for those of us here in Aus. During the warmer days we are experiencing, your HR is going to increase as your body works to cool itself. We send blood to the skin areas, to assist in this cooling meaning less blood is available for our muscles. Meaning yep you guessed it, increasing HR, to allow our bodies to compensate for both the work we are doing and the cooling we need.

HR Training Zones

Another challenge we have is defining the zones you want to train in and what your maximum HR value is. Whilst there are calculators to do this, they are based on broad averages. Ever heard of 220 minus your age? With something as generic as this for calculating a training value, there is going to be a high degree of error and a complete lack of individuality.

To get an accurate measure of your max HR, you need to complete a graded max HR test, and such a test may not necessarily be appropriate if you are new to training. So straight from the start if you are using HR and a generic benchmark, your training starts from a flawed position.

When using HR as a target during training, it is a lag indicator. Think of doing a shorter interval, under 90 seconds; it can take until the end of that rep or getting to the top of the hill, for your HR to reach the target you have set as the goal. How are you supposed to pace a rep, whilst not getting the feedback about the intensity till the end?

Coupled with the impacts listed above, you won't get a consistent value to base your training against, it's always playing catch-up.

Inaccurate readings and devices

We've covered some of the science, and what about the device and readings themselves? Wrist-based HR since its arrival have been notoriously inaccurate. Excuses being too sweaty (you're running of course you're sweating!!!) too cold, watch too loose, another HR monitor nearby, recording and in my pocket, my HR was showing as 250bpm! If I am going to make decisions and plan training based on data, I want confidence it is accurate. Otherwise, I am making wrong decisions that will impact your training, potentially in an adverse way.

The key point, your training zones and targets could be well off from the intent of the session!

So what are your alternatives?

The benchmark we want to base training on, and the anchor point is our critical power or critical speed (CP/CS), which we know is also close enough to our lactate threshold value. What metric can measure this accurately, is not impacted by weather, caffeine and records accurately and in real-time as your intensity changes? Enter running power.

Running power started in 2015 with Stryd and is now a common feature on Garmin, Coros, and Apple watches as a captured metric. We are only in the early days, and there is still some resistance, mainly from people who are ill-informed and not willing to change their ways. The challenge is, that not a lot of people are aware of it, or how to use it correctly to prescribe training.

Those from a cycling background have been using power meters for a lot longer, and in the pro peloton, it is now the metric of choice.

Running power as a metric facilitates incremental improvement in monitoring training/racing intensity and in monitoring training load versus more established technology, yep, HR. We are now seeing more elite athletes use it as a metric, and I believe this will start to trickle down to mainstream use.

As a coach who has used it myself for the past several years and coaching a number of athletes who are successfully training and racing with it, you don't have to wait! Don't let your training and data be based on inaccurate numbers and old technology. We used to think the earth was flat, it is time for progress!

Have a great week, wherever your running takes you.

Cheers,

Ash