Heart rate on a four hour ride in which I attempted to ride at Heart Rate Zone 2 (110-135 bpm.) I was mostly successful doing that for the first 2½ hours but then my heart rate began to drift upwards even while I kept my effort constant, a phenomenon known as decoupling.
I need to begin with a confession. I am not yet using the heart rate data provided by this device 100% correctly. Specifically, I have not properly defined my heart rate zones. Different heart rate zones are supposed to correspond to different physiological states such that exercise in these different zones have different training benefits. Most important to me at the moment is that, according to most coaches, including Coach John Hughes who I follow, training to improve endurance should be done in Heart Rate Zone 2. The problem is that the heart rates corresponding to Zone 2 will be different both for different coaches and, even for the same coach, will be different for different athletes. Because I am following Coach Hughes, the coach-specific part of this is taken care of; Coach Hughes says Zone 2 has a lower boundary of 69% of my anaerobic threshold heart rate and an upper bound of 83% of my anaerobic threshold heart rate. My responsibility as an athlete is to determine my anaerobic threshold heart rate. But what is an anaerobic threshold heart rate and how would I go about determining mine? I have blogged a very detailed discussion of the physiology relevant to that threshold but operationally the usual way to determine that is to measure my average heart rate during a time trial. Different coaches have different versions of this. In 2014, the version I was using was the average heart rate during the last 20 minutes of a 30 minute time trial. Back then, I rode three such time trials and my average heart rates were 161, 162, and 163 bpm for those three rides. For the sake of simplicity and as an acknowledgement of the uncertainty in that measurement I called it 160 bpm. That was fine back in 2014 but most definitely should be updated now, eight years later. I have some weak evidence from the 50 or so rides I have tracked with the TranyaGO that my anaerobic threshold heart rate may not be very different from what I measured back in 2014 so that is what I am using until I can repeat that measurement. Using the 2014 value of 160 beats per minute means that, for me, Zone 2 extends from approximately 110 to approximately 135 beats per minute. (Again, I rounded the numbers slightly for convenience.)
The first ride I did with the TranyaGO was to wear it while riding on my trainer as an easy way to see if it worked. I learned two things from that ride: 1) It works. I varied my pace and compared my heart rate as determined by holding my fingers against my wrist and counting beats to what was reported by the TranyaGO and they were the same. 2) I mostly use my trainer for recovery rides, 30 minute rides at 60 rpm at low resistance. It turns out that my heart rate on such a ride is just below 90 bpm, definitely a Zone 1 ride which is what a recovery ride is supposed to be. That said, based on this result, I have revised my Trainer ride slightly. Looking back on all the heart rate zone recommendations I have accumulated over the years, I rediscovered one from the Mayo Clinic. For training purposes, I am sticking with the recommendations of Coach Hughes, but the Mayo recommendations concern not training but exercise for health; they are about what constitutes “Light”,”Medium”, and “Vigorous” exercise according to the medical community. The recommendation of the medical community is that I engage in at least 300 minutes a week of Moderate exercise or 150 minutes a week of Vigorous exercise or any combination of the two. The medical community gives no credit for Light exercise. A complication in calculating the Mayo numbers is that they are based on my Maximum Heart Rate rather than my Anaerobic Threshold Heart Rate. Maximum Heart Rate is much more difficult to measure and arguably, my doing so would be risky for an old man like me. What I have done is estimate my Maximum Heart Rate at 180 bpm based on weak evidence from the TranyaGO rides I have done to date. Using that estimate, the Mayo “zones” are below 90 bpm for Light Exercise, 90 to 126 bpm for Moderate Exercise, and 126 to 153 bpm for Vigorous exercise. These zone definitions have all sorts of implications but for the purpose of this post I will just note that my Trainer rides are, for training purposes, supposed to be in Zone 1 which, according to Hughes, is below 110 bpm. However, if I ride them above 90 bpm, they count as Moderate exercise for health purposes; I get credit for them! Thus, I have been wearing my TranyaGO on the trainer and monitoring it as I ride to try to keep my heart rate between 90 and 110 bpm during these rides.
A few days after the Trainer ride described above, I wore my TranyaGO on an Alpine-Like ride. Alpine-Like rides are some of my most frequent rides as well as the rides I had been using to assess my fitness. (This is the one ride for which I have heart rate data from my old heart rate monitor.) For that ride I used the TranyaGO real time; I kept my eye on my heart rate as I rode and based on that attempted to keep my ride within Zone 2. Even doing that, 14% of the ride was at a heart rate above Zone 2. Before getting the TranyaGO I had been arguing that it was impossible for me to do a pure Zone 2 ride in the hills in which I live, and the TranyaGO seems to confirm that pessimism but also suggested that if I cannot do a perfect Zone 2 ride, I can do a better one. Before getting the TranyaGO, a typical Alpine-Like ride was 50% above Zone 2. Reducing the "too strenuous" fraction of an Alpine-Like ride from 50% to 14% is such an improvement. But there is a price for that improvement, my average speed on that ride fell dramatically. My overall average speed on all my Alpine-Like rides is 12.3 mph, and in fact the ride where 50% of the ride was "too fast" was ridden at 12.3 mph. When I used my TranyaGO to keep the "too fast" part of the ride down to 14%, my speed fell to 10.8 mph, a speed at the lower 2% of my rides. More recently, I wore the TranyaGO on an Alpine-Like ride where my goal was not to stay in Zone 2 but to see how fast I could comfortably ride it as a way to estimate my current fitness. I rode it at 13.3 mph, in the top 3% of my ride speeds. My heart rate during that ride was above Zone 2 almost 100% of that ride, it was essentially a Zone 3 ride. I have been speculating for some time that how fast I ride an Alpine-Like ride is an important parameter affecting my training program and the TranyaGO has confirmed that.
As described in my previous TranyaGO post, using the TranyaGO real time, watching my heart rate while I ride, is difficult on the road. (It is more do-able on my trainer.) In fact, the one ride described above is the only road ride where I have tried to do that. In every other road ride with the TranyaGO, I put it on, set it to record, and then ignore it until the ride is over. I then upload the results to my computer and compare them to what I was attempting to do, providing feedback that helps me evaluate the training I actually did rather than what I had planned to do and helps me better calibrate my next ride.The subtext of this is that I am bad at using Relative Perceived Exertion (how fast I feel like I am riding) to assess the Intensity (strenuousness) of my rides. Recently, I have been riding my 1963 Bianchi Specialissima over one of my old routes from my San Carlos days. (I will be discussing that route in more detail in a future post.) One reason I started doing those rides was, because this route is less hilly than the rides I can do in Emerald Hills, I thought it might be easier to maintain my Intensity in Zone 2. In my first attempt, over 50% of my time was spent below Zone 2, in Zone 1. That ride was much too easy, giving me too little training benefit. So, a few days later, I tried again. In that second attempt, more than 50% of my time was spent above Zone 2, the ride was too strenuous to provide a maximal increase in my endurance, which is what I am working on. On the third attempt, 9% of my time was spent below and 8% above Zone 2, so that over 80% of the ride was in my target Intensity of Zone 2. This is how the TranyaGO is helping me, it gives me the feedback I need after a ride to help me calibrate the Perceived part of my Relative Perceived Exertion.
I want to mention one more thing I have learned from my TranyaGO. Recently, I have been trying to do some longer rides on a routine basis. The route that I am using for that is 45 miles long and takes me about four hours to complete. My next longest “GoTo” ride is 33 miles long and takes me just under three hours to complete. I have gotten pretty good now at keeping my 33 mile ride in Zone 2 but on the 45 mile ride, that breaks down after about two and a half hours: my heart rate drifts upwards. What I believe is going on is something the coaching community calls decoupling. I think if I had been using a power meter to measure my output on that ride I would have found that I was not riding more vigorously for the last hour and a half but rather my heart rate was increasing at constant effort, the definition of decoupling. That actually makes a lot of sense. My body is used to riding for two or three hours, but when I go beyond that, the length of the ride itself becomes a stressor and in response my heart rate increases. What this means is that my 45 mile ride generates much more fatigue relative to my 33 mile ride than just the difference in durations would suggest.
I feel like the TranyaGO has really benefitted my training, a conclusion I admit is subjective. Because it encourages me to slow down to stay within Zone 2, I feel like I have been able to ride more miles with less fatigue. Before the TranyaGO, I felt like my risk of overtraining after my move to Emerald Hills had increased. I now feel like the TranyaGO has reversed that, that now my risk of overtraining is lower than it was before the move. But only time will tell. Stay tuned.
* I have had between 3 to 5 instances of “glitches” with the TranyaGO. Some or all of those might have been due to user error.
