I received a question on gauging recovery status from heart rate and power. I have almost two years worth of power and heart rate data, so I thought I would detail my experiences. Keep in mind every rider is different, and there are many variables outside of my training logs and data, so your results may vary. You’ll also see that I can’t always find the cause for variations in power and heart rate in my own data. Below are power files from 2010 and 2011. I’ve tried to focus on ‘threshold’ efforts of 30-50 minutes long, and selected the final 20 minutes for comparison. Also note although my power has steadily increased over the last year, the good and bad days are still quite obvious in terms of average power.
Normal: How do I know what normal is? This takes time to learn. I’ve been training with heart rate since I bought my second edition The Cyclist’s Training Bible when I was 18. I did Joe Friel’s 30 minute test a few times and decided my threshold heart rate was 164. Over the years I have seen variations which are the topic of this post, but overall my threshold heart rate has remained largely unchanged. The only way to know ‘normal’ is to collect a decent amount of data from training and racing, and correlate the data with performance and sensations to verify what you believe to be your threshold heart rate. The majority of my power files follow these numbers.
Chart title format: Event, Date: HRavg/HRmax (WATTavg)
Chart legend: See below top chart
The tracings above are each some of my best power numbers from 2010. The average for 20 minutes is very close to 164 bpm, and the power is very close to my estimated threshold at the time. For those of you familiar with the Performance Manager Chart, my TSB was between +5 and +15 for each of the above efforts.
Low HR / Low Power: This is my typical indication of a state of fatigue. When I’m less fatigued I seem to see low HR but near-normal power. As fatigue deepens, power starts to fall as well.
Each of the above charts are examples of worsening fatigue. In the first chart my heart rate is about 5 bpm lower, but power is only slightly lower. In the subsequent charts my heart rate is at least 10 bpm lower and power is greatly reduced. Keep in mind the last chart was an all-out effort, but I only averaged 263w! My TSB on these charts ranged from -3 to -15.
Low HR / High Power: This is the race-ready state I aim for. When I am well rested, but still fresh enough for a top race performance I often see slightly lower heart rate but increased power.
This ride was the last of my taper for Gila. I had ridden for only one hour, one day, out of the previous six. I don’t have many power files like these because they only happen a couple of times per year. For this ride my TSB was 18.
High HR / Low Power: For me this is an unusual occurrence and has only happened once that came to mind. For other athletes, an abnormally high heart rate can be a more common sign of fatigue.
I was planning on riding to the top of flagstaff, but felt so bad I had to stop halfway on this ride. My power was marginal and my heart rate was sky high. The highest I have ever seen was 179 at my Vo2 Max test last year, and I rarely reach 177 even at a criterium sprint finish in a race. My TSB for this ride was -10.
Summary: Heart rate can be a key indicator of fatigue, but history, experience and attention to the numbers are required. If you don’t have a power meter, don’t worry too much. On the days where I am markedly fatigued with very low heart rate and very lower power I will also feel terrible on and off the bike. It isn’t quite as obvious when heart rate is slightly low, as it could be a very good or somewhat bad day. This again can probably be determined by recent training load and other indicators of fatigue. Also, the numbers overall support TSB as a good predictor of fatigue.