This was my first run after arriving in Utah. I knew that altitude would affect that first run, I just didn't understand how much. I chose a course with a few small hills, and they felt much hillier than they should have and I was much more out of breath during the run than I was used to. For everyday activities, I felt like I adjusted to the altitude in a few days, but it was weeks before running felt "normal" again.
Altitude comes up frequently when talking to runner friends across the country about running here. The assumption is that running at altitude makes you stronger, and makes running at sea level feel really easy. Interestingly, when I started digging into the evidence, I've discovered that it's actually a little bit more complicated than that. Here's what I learned:
- There is agreement that if you train at sea level, you should arrive at a high-altitude race location at least 24 hours in advance, and an additional day would be better.
- High altitudes mean "thin air," which means less oxygen. Your body responds by producing more red blood cells, which boosts VO2 max. In other words, there may be a "natural doping" effect of altitude training. But not everyone agrees on this point. Training at altitude may limit the paces you can train at, meaning that races at sea level don't result in faster times. There is actually a theory that living high and training low may be the optimal strategy (read more here).
- It is normal for your resting heart rate to be higher the first day you are at altitude.
- As mentioned above, people here will tell you that it takes only 2-3 days to fully acclimate to altitude, but my experience with running was that it look longer. Apparently, I'm not alone. According to this, it can take 21-28 days to fully acclimate, which aligned with my experience.
- According to the same source (and everyone who lives here), extra hydration is needed while you acclimate.
- There seems to be no agreement about the optimal altitude for training, how much time at altitude is best, or how to approach it.
Bottom line: if you train at sea level and race at altitude, try to arrive at least 24 hours in advance, hydrate more than usual, and realize that your paces may (or may not!) be slower than usual. If you train at altitude, the benefits may be more limited than advertised, but there may be some real benefit. As Runner's World points out (here), virtually all elite runners build some altitude into their training. If they believe in it, that's enough evidence for me!