Altitude

Just wanted to respond to a question on altitude training: I notice that many of the pros are training for the season in high altitude, is there a reason or benefit for that?

Yes, altitude training and living certainly has its benefits. Here is a basic explanation of how things work at altitude:

Barometric pressure is the force that determines the amount of oxygen that is available to breathe. At sea level, barometric pressure is high and the air is dense with oxygen molecules. As we travel uphill, the barometric pressure decreases and the oxygen molecules become more spread out. This does not mean that there is less oxygen at high altitude - the low barometric pressure just means that the same amount of oxygen is spread out over a larger area. This basically amounts to fewer oxygen molecules per square foot.

The human body will adapt to the atmosphere it is placed in (most of the time). There are two factors that determine the amount of oxygen your body can process: 1) number of red blood cells and 2) amount of hemoglobin in each red blood cell. If you are accustomed to sea level atmosphere and arrive at 7000 ft, your body will begin to adapt immediately. Short term adaptations include: breathing really hard. This is the feeble attempt that your body makes to bring more oxygen into your bloodstream. If you are on a bike, this generally results in two things: 1) gasping for breath and 2) riding really slow.
However, your body will soon begin long-term adaptations. Over a relatively short period of time (2-3 weeks) your body will respond to the change in altitude by producing more red blood cells and more hemoglobin. These adaptations will basically provide improved and more efficient delivery of oxygen to your muscles.

So, the reason that athletes live at altitude is so that their bodies make the above adaptations. By adapting to altitude, the body has greater cardiovascular capabilities than that of a sea-level dweller. An athlete can then compete normally at altitude and have a performance edge when they arrive at sea level.

While these sound like fantastic adaptations, living and training at altitude can be a slippery slope. There are also negative aspects to altitude living and training:
1) The quality of your VO2 training will decrease at altitude, even when you have fully adapted. By "quality", I am referring to the amount of power you produce in a given amount of time.
2) It takes longer for your body to recover from hard workouts at altitude, which translates into fewer hard training sessions (or maybe just more cases of overtraining.)

So, finding the optimal balance between quality training and quality recovery can be more difficult at altitude than at sea level. If you overtrain or detrain during the adaptation period, all of the potential benefits are lost.

Live High, Train Low -
This is a great and wildly impractical idea. The accepted "optimal altitude" is between 6800-9000 ft. This is sort of the happy medium altitude - most people will make the altitude gains and are still capable of quality aerobic training. The lower you can train, the higher the quality will be. So, just live at the top of a mountain at 8000 ft, and then drive down the mountain to 3000 ft to train. Perfect, right?
If you can afford to buy an altitude tent and spend at least 9 hours per day in it - then you may have a solution. Or, you could live at altitude and train low by using supplemental oxygen. They do this at the Olympic Training Center in Colorado Springs.

Live High, Train High -
- This is more practical - the quality of your VO2 training won't be great, but your Lactate Threshold will certainly benefit, as long as you pay close attention to recovery.

Live Low, Train High -
This combines all of the negative aspects of each - you greatly decrease the quality of your training and at the same time, your body will make none of the adaptations to altitude. Your perceived effort will be very high, even though actual quality is very low.

My personal opinion on altitude is that it can be useful when used intelligently. It is not magic though. The most important thing will always be sound preparation and a training plan that allows you to make your hard days REALLY hard and your easy days REALLY easy.

One other note to anyone who is considering altitude training or already lives at altitude - if you have low iron levels you will not adapt to altitude. Low iron will greatly limit the body's capacity to produce new red blood cells and without new red blood cells, the body cannot adapt. Women in particular - whether at sea level or altitude - it is a good idea to have your iron levels checked every 4-6 months.

Here are a couple of good resources on altitude that go into further detail:
- Altitude.org
- A. Baker and W. G. Hopkins

Thanks for the question!