“We all inherently know that people are different and respond uniquely to the personal and physical stress in our lives. Yet, we often forget this when we coach athletes according to precompiled plans that don’t take into account their unique characteristics or how they are responding to training. Monitoring physiological responses with tools like Oura provides that missing link.” – Marco Altini

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Marco Altini is the founder of HRV4Training, an app and web platform that combines training load with heart rate (HR) and heart rate variability (HRV) data from devices like Oura to help athletes monitor the effectiveness of their training routines.

“High quality physiological data can enable athletes and coaches to individualize training plans based on an athlete’s unique response. Oura data can be used to automatically capture long term trends that show if a training block is resulting in improvements or maladaptation.” 

In a recent project, Marco partnered with Jamie Stanley, a former elite-level triathlete. Now, Jamie is the ESSA sport scientist of the year, devoting his time to coaching world-record-holding, Olympic, and World champion athletes in Australia. Together, they analyzed six months of Oura and HRV4Training data to study the relationship between resting physiological data, training stressors, and performance as Jamie pursues his sub-2h 30′ marathon goal.

What Patterns Did They Discover?

Marco stresses the importance of monitoring HRV in spotting both expected and unexpected stressors during a training program to monitor how physical, emotional, and other demands impact an athlete’s life.

“For me, it all starts with HRV. HRV is the only practical, non-invasive, and cost-effective way we have to measure our autonomic nervous system (ANS) and therefore capture how our body is responding to different stressors (training, lifestyle, etc.). HRV can detect how individuals are responding differently to identical training sessions.” 

HRV Reveals When Your Training Load Is Too High

During fall, to prepare for his main goal of running a sub-2h 30′ marathon, Jamie trained for a half marathon and 10 km race.

Jamie’s Oura data is connected to HRV4Training, allowing Marco and Jamie to watch for these patterns:

  • Your Body Takes A Hit When Training: Increased training effort usually corresponds with an acute physiological response (lower HRV and higher RHR) indicating strain on your body in the 24-48 hours following a high intensity session.
  • HRV Bounces Back Under An Optimal Training Load: But over time, if your body is given the chance to recover, you’ll see a lower RHR trend and higher HRV trend than the week before. This suggests that your training is paying off!
  • HRV Doesn’t Recover With Unproductive Training: If your HRV doesn’t rebound, however, it may be a sign that you’re responding poorly to the training stimulus and it’s time to slow down.

In the image below, we can see how a high training load block produces negative results when Jamie pushes too far. His HRV drops, RHR climbs, and he reports feeling sick on Week 45.

For that same time period, the color coding provided by HRV4Training’s daily advice, prompts Jamie to take it easy.

“A hard training block should not lead to a permanent drop in HRV if you are well conditioned and ready to handle the training. If your HRV drops, reexamine if you’ve taken on an excessive load or introduced a novel training stimulus (a new sport or activity).”

However, over time, Jamie balances his training load correctly, and we see his overall HRV averages (his baseline) grow stronger with very little fluctuations — providing him with additional confirmation that he is on the right path.

“This is why physiological data can be so valuable, not only we can clearly see when training isn’t going well but it also gives us confidence that the body is adapting well when HRV is stable and within our normal values, or showing slow increases over time”  

HRV Captures The Full Picture Of Stress

Marco notes, “When interpreting physiological data, context is key. We use all of our data – Oura, subjective training load reports, and workout data from Strava or TrainingPeaks so we can actually understand what’s behind a physiological change and make meaningful adjustments.” 

HRV can go up or down for a variety of reasons, and even the best training plans can be derailed by unexpected stressors. On January 8th, right after one of Jamie’s recovery weeks, he was stung by a bee.

Jamie’s Oura data the next day captures the stress response and shows, despite a reduced training load, multiple signs of stress (his HRV dropped, his temperature and respiratory rate jumped).

Although Jamie tries to laugh the bee encounter off, the following week, HRV4Training flags that his body doesn’t seem to be handling the increased training load as well as it normally does, suggesting maladaptation.

“We can only take so much. This is why HRV is an invaluable metric, as it captures all sources of stress.”

Why Marco Trusts Oura

“If you build high level analytics relying on HRV data, you need to make sure the data you start from is accurate, and that’s what you get with the Oura Ring, which makes it really an easy choice. HRV4Training is a science-based tool that started as a research project. Aiming for the highest scientific standards and validity, we have integrated only with Oura as a source of night HR and HRV data at this stage.”

Having worked for the past decade at the intersection of technology, physiology, health, and performance, Marco has been exploring different tools that could allow a user to collect high-quality HRV data at night, an ideal time for assessing baseline physiological stress while your body is at rest.

“Oura is quite possibly the only validated device able to provide high quality HR and HRV data collected during the entire night, as well as to provide developers with great APIs and support for integration. The finger is the ideal place for PPG measurements, as the signal to noise ratio is much better than what you get for example at the wrist, which makes the Oura Ring such a reliable device.While many devices try to do the same and measure sleep as well as HR and HRV during the night, there are clear limitations in non-wearable systems (such as the ones placed under your mattress), as well as less obvious issues with how the data is analyzed and reported by others (for example using custom metrics or providing just a few data points per night).”

Tips From Marco

“When it comes to physiology, context is key: make sure to track relevant information for you (training, how you feel subjectively, and any relevant lifestyle changes). This will make it easier to better understand the important factors behind changes in metrics like your HRV.” 

  • All stress matters: “An HRV drop with no change in training load is most likely associated with non-training related stressors, such as psychological stress at work or at home. These can be the most challenging situations, try to take extra care of yourself (for example, while your physiology gets back to normal, avoid hard workouts).”
  • Keep it simple: “In most circumstances, getting the basics right leads to the largest effects. A consistent sleep routine, regular exercise, a healthy diet, forms of mindfulness and meditation, and listening to your body can go a long way in making sure HRV stays within your optimal range or goes back up quickly after a set back.”
  • Know your body: “Many factors play a role. In people with a regular menstrual cycle, the cycle phase can impact your training. We have supported research looking at the relationship between resting HR, HRV, and the menstrual cycle, highlighting a decrease in HRV during the luteal phase, which might have implications for training prescription and monitoring.”

What’s Next?

Over the years, Marco has published several papers about combining measurements of resting physiology (e.g., RHR & HRV) with workout data to enable athletes of all levels to track how their performance and fitness change over time — no need for fancy laboratory equipment or specific tests.

If you’d like to follow Marco’s work, you can find him on Twitter @altini_marco.

If you’d like to follow Jamie’s work (and training!), you can find him on Twitter @jamiestanley85.

HRV4Training is a paid app that enables you to import HRV data from devices, including Oura. Learn More.