Brandon Eleuterio


Low Altitude Training

Brandon Eleuterio
Tucson Mountain Park Run

Living in Colorado at 7,000 feet my body has become accustomed to operating at high altitudes. Recently, I took the bold step of moving down to Tucson, Arizona at around 2,400 feet, for a month. This was the longest period I’ve spent at low altitude since moving to Colorado 15 years ago and I noticed a few things.

What Happened?

Right away I noticed a difference in perceived effort. I felt fantastic! I could breathe! Simple morning walks felt way easier on my cardiovascular system.

My hard runs felt easier. On day one in Tucson, I ran a 5k time trial logging my best time in 3 years. The main limiting factor was leg speed and muscle fatigue. I noticed my max heart rate for this run was 2-4 beats faster than previous hard runs in Colorado.

My easy runs felt faster. I wear a heart rate monitor for my runs and target a specific range for my easy runs (< 129 BPM). At the same heart rate, my Tucson paces were nearly one minute per km faster.

Coming Back

When I returned to Colorado, my first run was an interval session I took from Lionel Sanders called the 1k Sammich:

I ran the intervals on an out-and-back dirt trail with a slight elevation change – downhill going out, uphill coming back – with a slight headwind (8 mi/h) on the uphill. The temperature was cold – 28°F with 62% humidity and a windchill of 20°F.

In hindsight doing intervals on my first day back was probably not the best idea. I cruised on the first leg, in fact, I had to hold back. But, as soon as I turned around for the return leg, it felt as though someone shoved 10 pounds of wet snow down my pants! My hands and face started to hurt in the cold wind, my lungs were burning, and my legs felt like wet noodles. The 4:10/km pace on the opening kilometer turned into 4:56/km on the final kilometer. My 400m splits declined as well: 92, 94 on the downhill, and 101, 102 on the return.

A Week Later

After my initial painful runs back at 7,000 feet, a week later, my easy efforts are feeling better. I’m not as fast as I was in Tucson, but I’m faster than I was before I left. Here are some sample easy efforts:

2/20/21Colorado40 min7:06126
3/13/21Tucson40 min6:10124
4/3/21Colorado40 min6:47125

Similar story with my speed sessions. Better than before Tucson, but a noticeable dropoff since my return. Both recent Colorado interval sessions have been a struggle. I haven’t been able to find that extra gear to go faster. Maybe I need to adjust my pace targets down for a bit or perhaps I should walk instead of jog between intervals?


If I extended my stay in Tucson, would my nearly 1 min/km pace advantage eventually fade or am I someone who generally thrives at low altitudes? Are there things I can do differently to optimize my training at different altitudes? What role do things like diet and sleep play? If I ate more carbohydrates would I adapt to high altitude faster?

How much of a factor is hydration? The air seemed comparably dry in Tucson, but I didn’t feel as thirsty there. As a result, my fluid consumption was down, although I tried to maintain a similar level of electrolyte intake.

What role did better weather play? More sun in Tucson meant more time lounging outside and more activity in the form of walks and bike rides.

Is there a benefit to doing periodic low-altitude training? Many athletes experience a benefit with the opposite strategy – live at low altitudes while doing periodic high-altitude training.

Next Time

Incorporate more rest into the transition back to altitude. My body likely needs more time to acclimate after a month at lower altitudes. In the future, I can see a huge benefit in dropping down in altitude for races.


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