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With
winter vacations around the corner and people choosing where
they want to plan their mountain vacation, some people may be
planning on doing a little training at altitude.
It has long been believed that altitude training can
improve performance at sea level and has been a favorite
strategy for competitive athletes for years.
However,
even though it is a popular training plan, the votes are still
out on whether training at altitude actually improves
performance.
The
idea that altitude training may be beneficial has traditionally
come from two sources.
The first was the observation that many very successful
middle and long distance runners came from areas of East Africa
at altitudes of 1500 to 2000 meters. It
was surmised that much of their competitive advantage came from
training at high altitude.
The
second was that is presumed that there is a benefit in
developing increased oxygen carrying molecules in the blood.
Living and training at altitude do seem to do this but
with several caveats.
The
increase in oxygen carrying capacity (increase in hematocrit)
that occurs at altitude is induced by low oxygen levels in the
ambient air. This
stimulates a molecule called erythropoeitin which causes the
production of oxygen carrying cells.
However, the initial rise in the percentage of
oxygen-carrying red cells is due to a decrease in the other
components that make up whole blood.
The
initial increase in hematocrit can be quickly reduced when the
athlete moves back to near sea level.
This doesn’t do much for endurance.
For
people who live and train at altitude for months or years, the
hematocrit may increase by 50% or more.
This may have an effect similar to blood doping
since the red blood cell level may remain elevated for several
days or weeks after return to sea level. What is unclear is if this natural “blood doping”
enhances performance significantly.
The
problem with studies that have tried to assess whether training
at altitude enhances performance is the difficulty and expense
of not only the study itself but controlling the extraneous
variables. This
makes it difficult to decide the issue once and for all. Also, the few studies that do exist offer little advice about
the optimum altitude to train at, duration of training or length
of stay at altitude for maximum performance.
There
are several disadvantages to training at altitude.
One glaring example is that there is a reduction in
maximum work capacity. This
means that there is an earlier onset of fatigue at altitude and
that training has to be less intensive than is possible at sea
level.
Another
important consideration for the sports medicine doctor treating
athletes training at altitude is acute mountain sickness.
Symptoms of acute mountain sickness include headache,
nausea, vomiting, irritability, fatigue, insomnia, and poor
performance. Most
cases are benign and abate with symptomatic treatment only.
The typical duration is three to five days.
Occasionally,
mountain sickness may progress to a more malignant condition. This involves edema (fluid) in the lungs and/or brain.
This is more commonly seen in mountain climbers and
hikers who ascend to very high altitudes.
Although this is a relative rare complication of altitude
training it is important to be aware of.
The
incidence of mountain sickness increases at increasing altitude
and rate of ascent. A
recent study demonstrated that nine percent of people suffer
mountain sickness at 2850 meters while 53 % are affected at 4550
meters.
Weekend warriors and competitive athletes alike
can have a great time in the mountains.
If you’ve had trouble at altitude before or if you’re
going for a specific purpose, it may be a good idea to talk with
your
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