HRV profiles of elite and age group Ironman champions – detecting positive adaptation
Over the past month, two gruelling Iron-distance races took place in New Zealand – Challenge Wanaka and Taupo Ironman New Zealand. For this blog post, we’re fortunate to share an analysis of the daily morning heart rate variability (HRV) readings from two champions – one from each race. The overall male winner of Challenge Wanaka, Dougal Allan, was generous to share his HRV data with us, alongside the overall age-group champion for Ironman New Zealand (10th overall) our very own, Dr Daniel Plews.
Photo credit: Aus Tri Mag and Korupt Vision
By now many of you have probably heard of HRV and will be using it yourself. In case you’re not, you can read more about it here. Briefly, measurement of HRV typically takes place in the morning upon waking, measured either using a heart rate strap to a smartphone in the case of the Elite HRV app, or even as simple as using your smartphone camera against your index finger in the case of the HRV4Training app. For both programs, the technology measures the beat-to-beat variation of your heart rate – how your heart is beating, either with lots of variation between beats, or not much at all, and how between-beat variation changes on a daily basis. Analysis of these data gives insight into the status of your nervous system, and whether you have a predominance of sympathetic (fight or flight stress system) or parasympathetic (rest and digest recovery system) activity predominating. By monitoring this every day, patterns emerge that can tell us if we are adapting to our training or not.
The HRV Data
Data shown in the figure was collected on smartphones using Marco Altini’s HRV4Training app, which we recently validated against ECG and Polar chest strap.
View full-size graphical representation here.
In both our champions, across the lead up to their successful events, we can see how at a big picture level, its all about the rolling average. When the rolling average (dotted blue line) trends upwards, towards the smallest worthwhile change (SWC, red bar), its generally indicative of heightened levels of parasympathetic activity (remember, rest and digest, or recovery activity), subsequently inferring adaptation to training is occurring. Put another way, the aim of our training is being realized. We were the first to show the importance of rolling average HRV values in preference to isolated day values in 2012, when we compared these variables in a triathlete adapting to their training and going on to perform well, against a clinically diagnosed overreached triathlete. This same “positive” adaptation profile seen here has been shown experimentally by both Yann Le Meur and Clint Bellenger, and we showed this pattern again recently using data from Olympic and World Championship Rowing gold medalists.
Thus, the utility of HRV is that it tells us whether or not the training load is appropriate relative to the individual’s current life situation. We’re all complex creatures – all unique – so the ability to tap into each individual’s response to training is useful. The HRV response varies from person to person, depending on their training status, genetics, life load, psychosocial and emotional responses to life, environmental stressors such as heat and altitude, and of course the response to different forms of training (high intensity, high volume, eccentric load, etc).
Photo credit: Aus Tri Mag and Korupt Vision
You’ll note that the variation between The Plews and Dougal is different. This may be because The Plews is a bit more anal in terms of his daily measurement consistency – he rarely misses a day. This highlights the importance of observing individual daily responses against a person’s SWC, and using more the rolling average versus any single daily measurement. Thus, it’s difficult to imagine using HRV to change training on a daily basis (micro level) by itself, without other variables alongside it, and presently we wouldn’t recommend it. However, when you use it together with other subjective measures and within the context of the training plan, its extremely helpful, and takes much of the guesswork away during those heavy training periods when you’re questioning whether or not to adjust the load. By gaining insight into whether we’re adapting or not with the HRV profile, it gives us a rich layer upon which more concrete decisions can be made.
The sensitivity of HRV is also shown in our data set with both guys. Check out the dramatic drop in HRV the day following the Iron-distance event. This drop is entirely expected due to the heavy stress of the race, and confirms that the HRV system works for us – it’s picking up what we’re looking for.
So we are highlighting two successful campaigns towards an Iron-distance event, showing clear adaptation periods of raised HRV above the SWC. An example of less successful build-ups from our observations resemble that which we showed in our 2012 paper, where we have reductions in HRV below the SWC, or a stagnant HRV. This is particularly the case with endurance athletes using predominantly low intensity high duration training, or athletes who’s training isn’t polarized.
The limitations of this data are that its only 2 subjects using 1-min morning measures taken using the HRV4Training smartphone app, and that The Plews only had 9 weeks of data available due to a job change. This meant a phone change, coupled with work travel to Dublin, resulting in some data loss during that period; the perils of life as an age-group athlete. However it’s rare to find longitudinal data in elite athletes winning pinnacle events, so no doubt this blog post will be of interest.
Finally, it should be mentioned that The Plews was using the HRV data shown herein to ensure he was seeing adaptation responses and was adjusting his training load accordingly, as we do for our athletes. For Dougal, his successful HRV response may be more or less chance, although of course based upon good communication with his experienced coach. Regardless, the 1-min morning sample on your smartphone device is really easy to use and can have important implications to successfully monitor your training. Cost is small – benefit is high.
So this is clearly a complex area, and we’re fortunate to understand it at a deep level, having researched it with our friend Martin Buchheit for the last 8 years.
If you’d like to know more about it, we’re happy to consult with you, or you may want to sign up through us to the discounted Foundations in HRV course. Enrollments are now closed for this period, but you can sign-up and receive a notification when the next course begins.
Get training, get monitoring!