How altitude changes your FTP: from Monterrey to Mexico City or Toluca
You're racing at altitude and your power isn't responding the way it does at home. Here's why FTP drops with altitude and how to adjust your expectations.
How altitude changes your FTP: from Monterrey to Mexico City or Toluca
You live in Monterrey, at about 540 meters above sea level. You train all year with a consistent FTP. You show up to ride or race in Mexico City, around 2,240 m, or Toluca, around 2,660 m, and your power drops. It's not that you're out of shape. It's physiology.
Why power drops at altitude
The higher you go, the lower the partial pressure of oxygen in the air. Even though the percentage of oxygen is the same, there are fewer molecules per breath. Your cardiovascular system has to work harder to deliver the same amount of oxygen to your muscles, and the ceiling on your aerobic effort comes down.
The practical result: the same perceived effort produces fewer watts, your heart rate climbs faster, and threshold and VO2max intervals feel very different.
FTP and altitude: how much it can drop
There's no universal formula, and be wary of anyone who gives you an exact number. There are, however, general ranges that are well documented in the training literature:
- Up to ~1,500 m: the drop is smaller and many cyclists barely notice it on submaximal efforts.
- Between 1,500 and 2,500 m: you start to feel it clearly, especially on efforts above threshold.
- Above 2,500 m: the impact is noticeable even in Z2, and maximal efforts drop significantly.
For a rider from Monterrey heading up to Mexico City (~2,240 m) or Toluca (~2,660 m), expecting the same FTP as at home on race day is a recipe for blowing up. The exact amount depends on your genetics, your history of altitude exposure, and how many days you've been up there.
What it means for your race
If you're going to race at altitude:
- Adjust your target pace. Your sustainable power goes down. If you go out as hard as you would in Monterrey, you're going to blow up before the halfway point.
- Use feel and heart rate as backup. The power meter is still the most reliable number, but interpreted in the context of altitude.
- Don't do your last hard day at altitude if you just got there. The first 2 or 3 days are the worst.
Basic acclimatization
Full adaptation to altitude takes weeks, not days. For one-off races, there are two realistic strategies:
- Arrive the day before or the morning of the race. You race before altitude fatigue catches up with you. It's what a lot of pros do for short events.
- Arrive 10 to 14 days ahead. You start seeing early hematological adaptations and better tolerance to effort.
The worst of both worlds is arriving 3 or 4 days before: you've already felt the full hit of altitude and you still haven't adapted to anything.
Adjust your expectations and your plan
Changing altitude doesn't mean you lost fitness. It means the same legs are working with less available oxygen. A well-designed plan takes this into account: which zones get adjusted, how the intervals are executed, and what to expect on race day.
If you have key races in Mexico City, Toluca, Zacatecas, or anywhere above 2,000 m, and you want to show up with a plan that factors altitude into your preparation, let's look at your situation in 1:1 coaching, or start with the training plans that adapt to your goal.