Our bodies are complex systems and trying to simplify them into simple data points, as often advertised, doesn’t work. Heart rate and heart rate variability (HRV) data alone won’t determine your status of fitness, recovery, stress, physical, or mental strain, but these metrics can give you some helpful and actionable insights.
Let’s unpack what our coaches look at and what they learn from athlete heart rate and HRV data.
Heart Rate and HRV Data
Heart rate and HRV, when monitored daily, can be helpful for understanding your own physiology when viewed in the right context. By tracking for an extended period of time, you can gain some insights into what’s normal for your body and observe how your resting heart rate and HRV responds to different stressors. When you detect a change in your observed pattern, it might be a cue to ask yourself how you are truly feeling. Are you feeling rested? Ready to train? Bit of a sore throat now that you are thinking about it? You might realize you actually do feel a bit run down and might be carrying some extra mental load from an issue at work. Maybe you are coming down with a cold. On the other hand, you might feel pretty good and like you had a good rest and are ready to train.
Read more: What is HRV?
HRV monitoring is a good tool to objectively check in with yourself and your readiness for training.
We can’t separate the mental and physical components of stress. Even though training is an enjoyable stress (most of the time!), it’s still stress, and your body doesn’t know the difference between good stress and bad stress. A shift in resting heart rate and HRV—like a lower heart rate and higher HRV—may indicate an improvement in fitness, or it may indicate fatigue. HRV can also serve as a canary in the coal mine since one of the key indicators of overtraining is the inability to get your heart rate into the higher zones.
Context is key
It is important to remember that data is heavily influenced by physical activity and sleep quality. That’s why it’s always best to measure resting HR and HRV at the same time, first thing in the morning. You can then compare that day’s heart rate and HRV with your normal range and review whether the data is in line with your historical physiological data.
Even if you measure while resting during the day, prior physical activity will cause larger changes in your physiology than mental stress. This makes it challenging to build a ‘stress monitor’ that accurately reflects what we perceive as stress. Acute physiological stress from exercise usually overrides other stressors and that can lead to our wearables misinterpreting it.
Assessing Stress and Fatigue
Exercise Data Insights
Exercise data can indicate acute fatigue or difficulty adapting to stressors. This can be analyzed using the aerobic endurance feature in an app like HRV4Training. Chronically, it shows progress by comparing internal load (heart rate) with external load (power or pace). We like that the HRV4Training app has a nice subjective questionnaire to help provide context and get more meaningful information out of HRV data. TrainingPeaks does not (yet) have HRV analysis built in.
HRV analysis provided by the watch makers themselves has not yet shown to be fully reliable, but if you are curious to make the most out of HRV monitoring, we recommend checking out the HRV4Training app and the wonderful work that Dr. Marco Altini has been doing in this area.
Conclusion
The goal of collecting and analyzing training data is to help you understand normal vs abnormal responses, acknowledge day-to-day differences, and realize that many changes are inconsequential. Adding a little context allows you to better use your data and will improve your level of self-awareness. A long-term training plan built by a professional coach will help you to balance your various stressors so that you can train more effectively and healthily.
If you’re curious about how your body responds to training and stressors, use your data like your coach would use it. Track your resting heart rate and HRV at the same time each morning and note any abnormalities. This can help you learn about yourself, track your progress, and adjust your training in a meaningful way.
It is always important to use data in addition to subjective perception, not as a replacement. Assess how you feel subjectively before looking at your measured data to determine if you are truly where you should be in your training cycle.
Written by Steve House and Chantelle Robitaille, MSc.