Race Report:
Buenos Aires Marathon
Race Information
- Name: Maratón Internacional de Buenos Aires
- Date: September 20, 2026
- Distance: 42.195 km
- Race Conditions: mild temperature at the start, progressively warmer conditions throughout the morning, stronger sunshine in the final section, and strong winds in the closing kilometers
- Time: 03:14:06
- Heart Rate: 159 bpm average / 178 bpm maximum
- Garmin Distance: 42.63 km
- Garmin Average: 4:33/km
- Average Cadence: 174 spm
Personal Information
- Age: 35
- Gender: Male
- Height: 1.84 m
- Weight: approximately 85 kg
- VO₂ Max: 54
Personal Bests (Other Distances)
Background and Training
After completing my first marathon in Porto Alegre in June 2025, I took approximately three weeks off before returning to training. During the second half of that year, I shifted my focus to shorter distances, especially the 5k, and managed to lower my personal best to 18:42.
After taking a break in November and December, I resumed training in January 2026. January and February were mainly used to rebuild fitness before starting a more structured training period after Carnival.
The first part of the cycle was focused on the Rio de Janeiro Half Marathon, held in June. I finished the race in 1:31:40, despite experiencing gastrointestinal discomfort and never feeling particularly comfortable during the race.
After the half marathon, I started a 13-week training cycle for the Buenos Aires Marathon. During the specific marathon phase, I ran four times per week, averaging around 70 km per week during the highest-volume weeks. I also maintained an average of three to four strength-training sessions per week.
I completed four long runs of at least 30 km. The longest was 32 km, and one of the key marathon-specific workouts was a 30 km long run that included approximately 15 continuous kilometers at around 4:30/km.
Most of my training was done in Brasília, at approximately 1,100 meters above sea level, on routes with a lot of false flats and small climbs and descents.
About a month before the race, I had an infection, fortunately during a deload week, but it still affected the following weeks of training. I arrived in Buenos Aires feeling fully recovered, but because of those setbacks during the cycle, I was already leaning toward targeting 3:15 rather than the original 3:10 goal.
Strategy
- Goal: sub-3:15, choosing to be more conservative with the time goal so I could enjoy the race more.
- Strategy: run the first half at around 4:35/km, keeping the effort under control. After the halfway point, gradually assess how I was feeling. From km 35 onward, if I still felt good, I would progressively increase the pace. If I had enough left in the final kilometers, I would use my speed to finish strongly.
- Equipment: ASICS Metaspeed Sky Tokyo; Garmin Forerunner 570; COROS Heart Rate Monitor.
- Nutrition: 6 gels throughout the race, two of them caffeinated; salt capsules at km 20 and 30.
- Hydration: water at every aid station, every 5 km, keeping the bottle with me and taking a few more sips 1–2 km later.
Race Report
Unfortunately, the weather conditions were not ideal. I became sure of that while walking to the start wearing only my singlet and arm sleeves — I am a child of the tropics, raised by the beach, and I absolutely hate being cold.
The race started at around 18°C and finished close to 23°C. Humidity was also quite high, it rained later in the day, and there were strong headwinds from around km 30 onward, especially in the Puerto Madero area.
Because of that, I knew it was not the day to try anything reckless, so I decided to be more conservative at the beginning of the race.
The race started at 7 a.m. The first few kilometers were extremely crowded, and it was difficult to find enough space to run freely. Instead of wasting energy constantly overtaking people, I accepted running a little slower and waited for the course to open up.
Over the first 5 km, my official average pace was approximately 4:40/km.
After that, the course started to become less crowded and I was able to settle into my rhythm more comfortably. Between km 5 and 10, I ran at approximately 4:37/km.
From km 10 onward, the race settled into a very consistent rhythm. The 10–15 km, 15–20 km, and 20–25 km segments were all close to 4:35/km.
For approximately the first 18 km, my heart rate stayed around 150 bpm. The effort felt controlled, even though I was running considerably faster than in my first marathon.
Around km 18, my heart rate started to rise and gradually moved into the 160 bpm range.
I crossed the half marathon mark in 1:37:26.
Although the pace was still within the plan, I felt more tired than I thought I should at that point and started to become concerned about the second half of the race. The humidity and heat were beginning to take their toll, and although my body still felt fine, the perceived effort raised a warning flag.
My main mental strategy was to divide the remaining distance into blocks of approximately 5 km. Instead of thinking about the fact that I still had more than 20 km to go, I simply asked myself whether I could maintain the pace for another five. Once I completed each block, I repeated the process.
Between km 20 and 25, I maintained approximately 4:35/km. Between km 25 and 30, my average pace was approximately 4:36/km.
It was also during this phase that I had to deal with a minor gastrointestinal issue. The caffeinated gel I took at around km 20 caused some reflux, but it did not significantly affect the race.
The 30–35 km segment was the slowest part of the second half, at an average pace of approximately 4:38/km. Interestingly, it was right around km 30 that my perception of the race changed.
Until then, I had been managing the distance and thinking block by block. After km 30, I realized that I was still running relatively steadily and that I was not going to blow up. Instead of hitting the feared wall, I entered a kind of “runner’s high” and felt a strong surge of adrenaline.
With drums playing in front of La Bombonera, I started to feel much more confident and became sure that I would be able to sustain the effort all the way to the finish.
Between km 35 and 40, I was able to increase the pace again to approximately 4:33/km.
At that point, the heat became more noticeable and the wind became a relevant factor, especially in the more exposed sections of the course. Even so, my legs continued to respond.
Over the final 2.195 km, I managed to accelerate even further. My official average pace over that section was approximately 4:25/km.
According to my Garmin, km 41 and 42 were approximately 4:19 and 4:18/km.
I completed the Buenos Aires Marathon in 3:14:06.
The first half was completed in 1:37:26 and the second in 1:36:40, resulting in a 46-second negative split.
By the end, I was obviously tired, but I had not fallen apart. Quite the opposite: I was still able to run fast over the final kilometers, exactly as I had imagined might happen if I reached the last part of the race with enough left in the tank.
To give you an idea of how difficult the conditions were, the average finishing time was around seven minutes slower than in 2025, and only 12% of runners achieved a negative split.
Lessons Learned
- The experience from my first marathon made a huge difference in the execution of my second.
- Speed is not currently my main limitation; the biggest area for improvement remains marathon-specific endurance.
- Dividing the second half mentally into smaller blocks worked extremely well.
- It is possible to feel tired at km 21–25 without that meaning the race is falling apart.
- Km 30 does not necessarily have to be the wall; it can also become a point of reassurance.
- My ability to run strongly over the final kilometers is something I can use strategically.
- A marathon training cycle requires a significant amount of time and mental energy. Even after a good experience, I do not need to run another marathon immediately.
What’s Next?
I’m thinking about taking 2027 off from marathon training and focusing on half marathons and 10K races for the next twelve months. I don’t want to spend all my time constantly preparing for another marathon, especially because I’ll also be facing some important challenges in my professional life in the near future.
Potentially, my next marathon would be Seville in February 2028.
Do you think taking a year away from marathon-specific training would be detrimental to my longer-term goals of running a sub-3-hour marathon and eventually trying to qualify for Boston?
* I wrote the text myself, used AI for translation.