Running the Numbers

My Year-long Journey to the Berlin Marathon

Greetings 👋🏻, I'm Matthias, a 34-year-old male, and resident of Brooklyn, New York. My sports background mainly featured soccer, and as for running, it was more of a casual whenever I felt like it kind of thing. You know, those Sunday mornings where my sneakers and I would negotiate the terms of our workout 🤷🏻‍♂️. But then, an interesting shift occurred. I became determined to transform into a more dedicated runner 🏃🏻‍♂️. My objective? To conquer a Marathon, not just to complete it, but to do so with the finesse of proper training and a genuine appreciation for this sport that had slowly grown on me. And here's the twist – I happen to be a data scientist 📊. Yes, the one who crunches numbers for a living. The collision of my newfound passion for running with my penchant for data led to an intriguing idea: why not collect and analyze my running stats while I'm at it? Thus, I find myself here, sharing my journey in a bunch of charts. It's a transition from the occasional jogger to a Marathon enthusiast. So let's run the numbers!

Fig 1: Pace by run

It was a delightful morning on Labor Day 🌤, precisely on Monday, September 5, 2022, when the seeds of my commitment to running more seriously were planted. My destination was Central Park, and I downloaded Strava to keep tabs on my running speed. This marked my very first foray into tracking my runs, and from that moment forward, I meticulously documented each and every run I undertook. My average running pace, shown in the figure below, became a first key metric that I was interested in.

Fig 2: Distance by run

This histogram serves as a visual diary of my running adventures, illustrating my evolution from a runner who once believed that an hour-long run equated to an eternity, to someone regularly tackling distances greater than a Half Marathon twice a week. I distinctly recall the sense of accomplishment when I completed my first 10-mile run. Over time, I integrated one long run per week into my training, but I learned the importance of gradual increases in distance to avoid overexertion 📈.

Fig 3: Heart rate by run

Eventually, I came to appreciate the significance of monitoring my heart rate 💛 and invested in a Garmin watch. Initially, I was solely fixated on pace, always chasing speed. However, it didn't take long for my heart rate data to reveal a different story - I was pushing myself too hard 😥. Shifting my focus to heart rate brought a profound change. It not only helped me enjoy my runs more but also steered me toward a more balanced approach. I delved into learning about heart rate zones, recognizing their pivotal role in optimizing training. This became particularly important, once I increased my overall volume and incorporated true recovery runs into my schedule. I realized a heart rate somewhere in the ~130s is ideal for that purpose. I would often execute my (medium) long runs as so called steady runs at the ~150s range, which roughly aligned with my aerobic zone 3.

Fig 4: Total distance by week

I progressively increased my weekly mileage, diligently working my way up to a first milestone of approximately 30 miles. After this consistent 12-week period of incremental growth, I decided it to grant myself a well-earned respite. This prompted the establishment of a new structured routine, characterized by alternating between running, racing, and recovery weeks. Subsequently, I transitioned into a more formalized training program 📅, specifically adopting Pfitzingers 12/55 Marathon plan. This choice brought a heightened level of structure to my training regimen. My dedication bore fruit as I successfully completed the Brooklyn Half Marathon in a time of 1:27:51. Following a brief intermission, I embarked on a subsequent (slightly adjusted) cycle of Pfitz 12/55, this time with the grand objective of preparing myself for Berlin 🇩🇪.

Fig 5: Heart rate vs pace

This figure offers an insightful glimpse into the relationship between my average heart rate and pace during various runs. As expected, it showcases a robust and logical linear correlation – a testament to the precision of heart rate as a marker of effort in running. The variations of heart rate for different runs at roughly constant pace highlight improvements as my training progressed. Early on, I've learned pushing myself to the limit strategically. Notably, during races, I would leave it all out. During the Brooklyn Half Marathon, I maintained an average heart rate of 180 beats per minute. This effort level, coupled with my maximum heart rate of 194, placed me well above my lactate threshold, and I actually have no idea how I survived 😅.

Fig 6: Smoothed heart rate and pace over time

I aimed to gain insights into the progression of my running pace and evaluate whether these paces came easier over time. To achieve this, I devised a unique convolutional smoothing method to analyze my average running pace and heart rate, allowing me to identify long-term trends. The figure presented below illustrates these trends. It is truly fascinating to observe how I managed to increase my running speed while expending less effort. But then, summer crashed the party like an unwelcome guest, and I had to face the stark reality of how heat and humidity are the evil twins of running performance. I hit a slump, and by July, my effort sprang back up like it had just discovered a trampoline. But it dawned on me that my fitness wasn't actually taking a nosedive; it was just enjoying a rollercoaster ride 🎢 with the weather. Looking back, I should have been adjusting my paces to keep my heart rate happy. As the temperatures cooled, I unlocked further improvements in pace leading up to the Berlin Marathon.

Fig 7: Smoothed compound fitness over time

In my pursuit to track my improvement, I defined a dynamic metric of compound fitness as the ratio between my smoothed pace and heart rate, which can also be expressed as meters per heart beat [m/HB] when you cancel out the units 💡. Additionally, there's also a weather-adjusted version of this ratio, accounting for the influence of heat and humidity on my performance. As we dive into the chart, a captivating storyline unfolds. It portrays a consistent upward trajectory, indicating a steady increase in my fitness level over time. Amid this encouraging trend, a distinct summer slump stands out yet again. This segment of the chart vividly illustrates how scorching temperatures and humidity impacted my performance, with a noticeable dip in the ratio during this period 📉. However, the data again reveals that this was not a decline in fitness but rather a seasonal challenge.

Fig 8: Total cumulative distance over time

In just a year's time, I managed to log over 2000 miles. To put this in perspective, that's roughly equivalent to running from New York City to Miami. It's like I became my very own Forrest Gump, minus the shrimp obsession 🦐. And somehow, I even learned to greet those early hours with enthusiasm. Running, they say, can turn you into a morning person. Who knew?

Fig 9: Runs binned by distance

During my Marathon preparation, I ran a series of different distances. I completed four 20+ mile runs, and tackled 17 runs ranging between 15 and 20 miles. These long-distance runs allowed me to work on my pacing and endurance, often with stretches of Marathon pace efforts. In addition to that, I completed 50 medium-long runs, spanning from anywhere between 10 to 15 miles. These mid-week runs became a staple of my training routine and played a significant role in my aerobic improvement 💪🏻.

Fig 10: Weight and active Calories

Embarking on a journey to become a better runner, I found myself shedding more than 20 pounds along the way. The calories I burned during these sessions were akin to devouring more than 400 Big Macs 🍔. Admittedly, the newfound commitment to running left me with a perpetual appetite, a testament to the effort I was putting in.

Fig 11: Berlin Marathon

After relentless training, I completed the Berlin Marathon in an official time of 3:10:16. It marked the culmination of my year-long journey. Standing at the starting line, memories of the early mornings and sacrifices flooded my mind. Amid the energizing atmosphere of fellow runners and enthusiastic spectators, I felt an overwhelming sense of readiness 🚀. It was an indescribable feeling. Once the gun went off, I maintained a conservative pace, mindful of this being my inaugural marathon. Thanks to holding myself back in the beginning of the race, I felt like a superhero 🦸🏻‍♂️ as I steadily passed competitors after about 20 miles, staying on target without relenting. Only the final mile proved challenging due to my tightening calves. But even as I crossed the finish line, I couldn't help but look forward with excitement to my next Marathon!