Apologies to The Ventures!
In my previous post I shared some thoughts on walking rather than running the run portion of a long course triathlon. To summarize, coaches always tell their athletes to hold back on the bike, not to pace it like an all-out time trial, because as soon as they get off of the bike they have to run a marathon. My current thinking is that I run so slow I might as well walk. This should allow me to pace the bike faster, and may result in a faster overall time, due to the lower metabolic cost of walking.
To be clear, when I say walking I do not mean a stroll in the park. I often hear the terms speed walking and power walking batted about. Without getting too deep into the weeds, let’s just say something like that.
I have been running for many years, but by no means all my life. I have trained for and run the Honolulu Marathon seven times, first in 2012, at the age of 62. I had to miss 2013 due to a hernia – all that running! My best time was the following year, 2014, when I finished in 7:26. Since then my times have gradually increased – I am slower now than when I started. I like to say that one reason I slowed down was my increased focus on triathlon, but in all honesty that does not explain my miserable run performance.
If you have been following this blog you know that something important began in 2020, and bore fruit this past March. After the 2019 race I realized that something was wrong with my heart. Even with lots of training I could only run slow, and after eight miles or so my heart rate would be way too high. Using a five zone system I was running at the start of zone two but my heart was near the top of zone four, a maximal effort sustainable for an hour at most.
I went to see my GP, who gladly referred me to a cardiologist. By the time I could get an appointment in March 2020 everything was closing down. He guessed I was experiencing some kind of arrhythmia but we needed a good EKG while it was happening to make a proper diagnosis. It was not until March of this year that I had the opportunity to run a race hard enough to trigger the arrhythmia and record it.
What about last year’s Honolulu Marathon? I bailed at the eight mile mark with my heart messed up. I knew I could have walked the rest, but I was so disappointed that I just did not relish the thought of walking another twenty miles. I went all through 2021 with no sign of the problem, and was running well in training leading up to the 2021 Marathon. Dr. Cogan had prescribed medication and it seemed to be working. For the race I was tight on carrying capacity and elected to not carry the Kardia portable EKG Dr. Cogan had asked for, so no recording.
The 10k last March was my next opportunity and I made sure to carry the Kardia. I was doing well enough that I did not feel like stopping, so I ran a strip right after finishing and got useful data to send to Dr. Cogan. The diagnosis: Premature Atrial Contractions (PACs). Not harmful like other arrhythmias, but, although I have not seen this stated explicitly, it seems to me that disruptions in normal heartbeats will decrease blood pumping volume, so your heart beats faster for a given effort. I’m pretty sure this has been going on for a long time. I just didn’t know it, and I still can’t be sure what the impact is.
Around this time my social media feeds were swamped with ads for a new kind of heart rate monitor, the Frontier X. Simply put, it works as a Bluetooth heart rate strap and at the same time records a continuous EKG. Pricey, but it has a 30 day satisfaction guarantee, so I bought one. Someday I will write a review. For now, take a look at this heart rate strip from last Sunday’s half marathon.
A few notes.
The chart time is time of day. The Frontier X must be recording for a heart rate signal to be transmitted to my Garmin watch, so when this strip begins I am standing in the crowd walking slowly toward the starting line. It should be obvious where we started to run. The gun went off at 6:00 but it always takes awhile for me to get to the start line.
I run with a 6/1 run/walk pattern. That explains the ups and downs in the first half.
I started walking about halfway through, around 8:30; you can see the drop in heart rate. Notice that it does not drop much – I was walking as fast as I could! My plan was to walk up Monsarrat from Campbell Ave. I walked all the way to the finish, with a sprint to the finish line. So much for plans.
The thin, vertical red line shows where an alert based on heart rate occurred. I set the alert at 151 because my target for this race was 135-140, based on recent training runs and that 10k a month back. 151 is my LTHR. Notice that it comes just before I decided to abandon running. If I was making 10 minute miles I might have kept going – 15 even. But I was down around 18 or 19.
The colored bands are not my heart rate zones. Frontier has some tracking AI going on (more about that in a later post) and I think they try to deduce them from past activity. That, or they are just arbitrary breaks.
What it is about this strip that piques my interest are all those small white rectangles with “O” in them. Those show where the EKG track is not normal sinus rhythm. Frontier does not attempt to say what they are,all they say is the “O” stands for “other” and offer no diagnosis as to what kind of arrhythmia they are, but knowing what I know and looking at the strip itself, I would say these are PACs. Lots and lots of PACs.
The PACs seem to occur most often when I transition from running to walking. You can see this clearly at the end. I sprinted the last fifty yards to the finish – you can see the spike in heart rate. From then on, an explosion of PACs.
Here is a chart from a two and a half hour easy run the week before the race. Notice how few PACs there are. The difference? A more comfortable pace, 20:00 min/mi.
In his book The Haywire Heart Dr. Mandrola describes stress as the major contributor to PACs and their ventricular cousins, PVCs. This could explain some or all of the difference between my training runs and my races. The thing is, I felt no stress at all leading up to the marathon, and the same goes for the half. But stress is a sneaky creature and cannot be dismissed lightly. The point is that my concerns are about race day, to achieve the best possible outcomes going forward.
For now my Plan A is to work on improving my walk skills, with the goal of being able to sustain better than 18 min/mi. Plan B is to work on improving my running skills to get me up and over that lump of inefficiency that happens in the transition from walking to running, the idea being that running a wee bit faster can be more efficient. I wish Plan B will work, but there is a reason why it is Plan B.
Last but not least, I present some data gathered from these recent races. I separated Sunday’s half marathon into two parts, running and walking. The data from December is from the marathon, but I only ran eight miles so the comparison is useful.
Comparison of recent run races
Metric
Dec 2021
Mar 2022
HM A
HM B
NP
121
127
127
103
Avg HR
146
147
143
135
Max HR
162
163
169
153
Pace
19:30
18:14
18:25
20:05
IF
0.76
0.87
0.76
0.62
My goal is to create a more efficient way to complete the run portion of a long course triathlon, that in conjunction with reasonable paces for the swim and the bike allow me to cross the finish line with a smile.