Nuances of Heart Rate Training for Runners (Part 2)

Hi there! 👋

As promised, this month we’re following up with the second instalment on the subject of heart rate training and scenarios where heart rate should be disregarded in favour of other better metrics of running intensity. 

If you missed the first email, you can read it, together with all our previous newsletters here. 

In brief, we discussed the fact that heart rate only gives us one fairly narrow view on how hard the body is working, and just because heart rate has not risen when you initially increase the intensity, doesn’t mean the body isn’t working hard and being exposed to a meaningful training stimulus. 

Let’s look at two more scenarios where you may want to overlook heart rate data…

2. Short Efforts and Sprints

With sessions involving sprints and short efforts (e.g. ~120-seconds or less) that have long recovery intervals lasting several times the length of the work interval, you’ll often find that heart rate only rises a little and doesn’t ever reflect the true intensity you’re running at, which is often maximal or near-maximal. For example, you generally won’t hit your max heart rate in a 60-second effort, even if you’re running as fast as you can. 

You may worry that, since the sprint session doesn’t elevate heart rate by much, it doesn’t count as a high-intensity session. However, if you think again about what’s happening at the muscles, you’re asking these to contract very hard and generate power and energy at a very high rate. This is unequivocally a high-intensity session. It’s just that this intensity is not captured well by looking at heart rate. 

We have seen athletes add additional high-intensity training into their week because they didn’t feel that a sprint session ‘counted’ as a proper high intensity session, due to their consistently low heart rate. But again heart rate only gives us one snapshot and adding extra high-intensity training is a fast-track to overtraining and injury!

Since sprints and short efforts are usually performed all-out or near-maximal, then it’s not really necessary to pace these efforts - you’ll generally just want to try to run as hard as you can for the target duration, and not worry about looking at metrics such as heart rate.  

3. Downhill Running

Our final example of when heart rate may need to be disregarded is when running downhill, particularly down a steep gradient. 

You may notice that it’s actually quite hard to keep your heart rate elevated when descending, and that you have to run really fast in order to do that. 

This places a high degree of eccentric loading on your muscles, as well as a lot of impact through your joints, and it can lead to considerable muscle damage and long-lasting muscle soreness over the days afterwards. 

Indeed, running fast down hill is a really good way to strengthen your muscles and condition them for hilly races. However, it’s not something you want to do too often due to the muscle damage, and it’s definitely not something you want to do in every run just in order to keep your heart rate in the target zone.

In most cases, we’d recommend just accepting a drop in heart rate on the descents, rather than aiming to pick up the pace too much. Your pace will inevitably increase a bit, but don’t push faster than feels comfortable, and instead just enjoy the descent, knowing that you’ll be building strength and endurance even if your heart rate drops. 

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A final point of note on the topic of heart rate training is that heart rate monitors are notoriously unreliable (especially if using a wrist-based monitor on your watch). So you should always pay attention to your pace, power (if you have a power meter) and subjective effort level, in addition to your heart rate, and trust your intuition if you think your heart rate monitor is reading incorrectly. I know runners who have paced a race off incorrect heart rate readings, despite knowing the effort felt too hard… there’s only one way that ever turns out, and it’s not good!

News

We have a new article on home-based blood lactate testing protocols for runners. This is a great way to set individualised training zones, understand your strengths and limiters, and track changes in fitness. We go right into the specifics of how you can do this type of testing yourself, without needing to visit a lab. 

We also now have a set of plans geared towards a 50-mile fell/trail race. These are suitable for races between 40-60 miles (60-100km), and up to 3,500m or 12,000ft of elevation. 

You can also check out our 50km and marathon trail/fell plans. 

All plans come with a detailed PDF user guide to help provide guidance you’d usually get from a coach, and the plans are tailored to three different runner levels:

• Improver: already completing 4-5 hours of running per week and comfortable with running at least 1-hour at a time.

• Intermediate: already completing 5-7 hours of running per week and comfortable with running at least 2-hours at a time.

• Advanced: already completing 7-9 hours of running per week and comfortable with running at least 3-hours at a time.

We’ll be adding more plans soon, and if there’s anything in particular you’d like to see, just drop us an email! 

That’s it for this month! If you’re relatively new to the mailing list and want to see previous instalments, then you can do so here.

Happy running!

Emma & Tom