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Short-Duration Altitude Acclimatization

The effects of short-term altitude acclimatization are varied and include both cognitive and psychomotor components.

From the Field

I am the Navy Sports Program Manager, and I have a question concerning high-altitude training. Our Armed Forces Rugby Championships are being held in Glendale, CO, this year. I would like to be able to have our team tryouts and training at altitude in preparation for the event. However, when speaking with several ATCs I was informed that our team would gain no advantage from training at altitude because of the short duration of our training camp. We will only be in camp nine days prior to the event. It was explained to me that that fitness levels actually decrease during the initial stage of training at altitude and hit bottom around the seven-day mark.

Can you please shed further light on this subject? I want to give our team all the advantages that I can, but I certainly don't want the training at altitude to be detrimental.

HPRC's Answer

Short-duration altitude acclimatization

The quick answer is: All things being equal, a team that has been training at altitude for a week or longer will beat a similarly skilled team that has been at altitude for only a day or so. Training for nine days at the same elevation that the subsequent competition will be held will not be detrimental to your rugby team. In fact, it will be advantageous.

According to an extensive review, when un-acclimatized sea-level residents are rapidly and directly transported to altitude, there is an immediate reduction in maximal aerobic capacity (or VO2max) that is directly proportional to elevation. According to the U.S. Army Research Institute of Environmental Medicine’s Altitude Acclimatization Guide, submaximal physical performance is initially compromised at altitude, and the amount of decrement varies based on the activity duration. Of particular importance is that pulmonary ventilation increases over the first seven to nine days at altitude with the majority of this change completed by the fifth day, at which time submaximal exercise improves.

The elevation of Glendale, CO, is 5,280 ft. At this elevation, the average expected VO2max reduction would be 5–10% relative to that at sea level, and there will be no improvement for at least three weeks. After a few days at altitude, even though VO2max will not increase, the ability to perform the sports activity will improve because of altitude acclimatization (specifically ventilatory and circulatory acclimatization). Athletes will generally be able to perform for longer periods of time at a higher proportion of VO2max after a week at altitude than they were able to do in the first couple of days. This will provide a competitive “edge” relative to those who did not train similarly at altitude. There is little objective scientific data to support the concept that fitness levels will be lower at seven days than they were on first arrival. Go to Glendale, CO, nine or so days ahead of the competition date as planned to gain as much altitude acclimatization as possible before the competition.

After the first couple days at altitude (which are likely to be uncomfortable), the athletes will have minimized any potential adverse effects associated with long-distance travel and time-zone changes. Sleeping will be more restful, and no one should be lightheaded or suffering from acute mountain sickness during the competition. Training for nine days at altitude will also provide your athletes “competitive acclimatization” that will allow them and your staff to get used to the altitude and properly adjust rates of player substitutions, rest periods, etc. Please realize that it takes longer to recover at altitude than at sea level. Make sure everyone drinks plenty of fluids, and increase the carbohydrate proportion of each meal. For additional information, you may be interested in reading the “Missions at Altitude” section in Chapter 15 of the Warfighter Nutrition Guide.