Notes on Randall
Wilber's "Altitude Training and Athletic Performance"
John's comments in
italic
Part I: Potential
physiological benefits
Effects of altitude
on training:
Upon exposure to
altitude, the body makes several adjustments.
*Cardiac output and
stroke volume, both in submaximal and maximal exercise, drops.
*Ventilation, that
is, the total flow of air in and out of the lungs, increases.
*This increase in
ventilation, coupled with hormonal changes causing an increase in urination,
gives rise to a great increase in the body's demand for water. Fluid intake at altitude, especially during
the acclimatization period, should be as much as 4-5 L per day.
*Lactate buffering is
impaired during adaptation to altitude because the increase in CO2 exhalation
disrupts the equilibrium of the bicarbonate buffering system, allowing H+
to accumulate faster.
*In men, carbohydrate
utilization increases; that is, a larger proportion of the athlete's daily
energy comes from carbohydrates. Women
maintain a similar level of carbohydrate and fat utilization vs. sea
level. Both genders will likely need to
increase their caloric intake, but men in particular must consume extra
carbohydrates. High-glycemic food ought
to be consumed immediately after exercise at altitude.
*The body demands
more iron to produce red blood cells.
Unsuplemented, the ferritin levels of lowland athletes training at
altitude often drops significantly.
Furthermore, athletes who are iron-deficient upon ascent (defined in one
study as men with <30 ng/ml ferritin and women with <20 ng/ml) respond
very poorly to altitude. Therefore, iron
supplements are a necessity. Not only
solid iron sulfate, but so-called "liquid iron" might be a good idea
too. One study prescribes 5-45 ml/day of a 9mg/ml liquid iron solution,
depending on ferritin levels.
*The increase in
oxygen demand, coupled with increased training at altitude, results in an
increase of cortisol, a stress hormone.
Cortisol can impair training and depress the immune system, making
athletes more susceptible to illness. It
can also cause muscle catabolysis, where the body "eats" its own
skeletal muscles. This muscle
catabolysis may be able to be counteracted by consuming protein after exercise
and before bed
*Oxidative stress
increases, possibly because of the increased oxygen consumption, increased UV
exposure, and free radical production.
Oxidative damage can result in fatigue, DOMS, and injury. Wilber suggests supplementation with 400mg of
vitamin E per day to counteract oxidative damage. Wilber also mentions sunblock, sunglasses,
vitamin A, and vitamin C. Other (and
more natural) antioxidant sources, such as tea, pomegranate juice, blueberries,
and grape juice, will likely also go a long ways towards protecting the body.
*Under proper diet
and hydration, body composition should not drastically change.
Performance is
hampered at altitude for a few reasons:
*Reduced partial
pressure of oxygen: Arterial oxygen delivery works by diffusion. O2 diffuses from the air into the
blood, then from the blood into the muscles.
This diffusion is governed by a difference in partial pressure. Hence, with a lower ambient PO2,
diffusion does not happen at as high of a rate, and the arterial blood
saturation % drops.
*Decrease in
maximal oxygen consumption: probably
related to the reduction of PO2.
Because blood passes through the lungs too quickly to be fully
saturated, the maximum rate of oxygen consumption decreases vs. sea level
conditions. This leads directly to a decrease
in VO2 max.
*Decrease in
training capacity: the lack of available oxygen necessitates a slower pace
during intense intervals, which can lead to less quality in workouts.
*Sprint work, at
least with full recovery, is not impaired at altitude, and is in fact aided by
the decrease in air resistance.
Training response to
altitude:
*The decreased
arterial saturation of O2 stimulated the kidneys to produce
erythropoietin (EPO), a hormone that stimulates red blood cell production.
*The lack of oxygen
also stimulates an increase in the number of mitochondria and the enzymatic
activity within them. Results are
inconclusive on whether altitude stimulates changes in capillary beds or muscle
composition.
Part II: Altitude
Training and Athletic Performance
*results from many
years of studies are inconclusive on whether altitude training improves
sea-level performance in trained athletes.
Problems result from poor methodology, lack of a control group at sea
level, different training protocols, and small study numbers.
*In a retrospective
investigation into "responders" and "non-responders," over
80% of "responders" (people who improved after altitude training)
were in the "Live High, Train Low" training group. The rest were in the traditional "Live
High, Train High" group.
*It is hypothesized
that the ability to do maximal and near-maximal training at near sea level
allows athletes to retain the training intensity of sea-level groups but reap
the physiological benefits of altitude.
*Of studies
supporting the benefits of the LHTH approach, the greatest benefits seem to be
from groups training and living between 7,000 and 10,000 feet.
*Of studies not
supporting the benefits of the LHTH approach, the only groups with
statistically significant DECREASES in performance, VO2 max, and
Hemoglobin levels lived and trained at over 13,000 feet. Therefore, we can conclude that, at the
very least, you will not get WORSE by training and living at altitude in any
city in the United States. Up to 10,000
feet seems to be a safe altitude.
*Recent well-designed
studies by Levine and Stray-Gundersen suggest that 1) LHTL is superior to
sea-level training for periods on the order of one month and 2) Base training
at altitude and faster training at low altitude (so-called "Hi-Hi-Lo"
training) is equally good From this, it seems obvious that the best choice
would be HiHiLo training, because it would save on trips down from the
mountains.
*One recent study
asserts that athletes can be divided into "responders" and
"non-responders" based on their blood EPO levels (% of sea level
baseline: responders had a blood EPO increase of ~156% after 30h and
nonresponders increased only ~137% of SL base) and total red cell volume
(ml/kg) (total red cell volume increased in responders significantly (~3.0
ml/kg) and remained unchanged in nonresponders). The "responders" should improve
greatly from altitude training. Possibility of testing this before and after
altitude training? Blood EPO is measured in IU/ml
"After 14 days at
altitude, Epo was still elevated in responders but was not significantly
different from sea-level values in nonresponders"
"In conclusion, after
a 28-day altitude training camp, a significant improvement in 5,000-m run
performance is, in part, dependent on 1) living at a high enough
altitude to achieve a large acute increase in Epo, sufficient to increase the
total red cell volume and V ˙ O2max, and 2) training at a low enough
altitude to maintain interval training velocity and O2 flux near sea-level
values."
Practical
implementation
Most successful
coaches and athletes recommend 7-10 days of acclimatization upon ascent to
altitude before intense training begins.
Programs differ during the "stress" phase, but it lasts from 2
to 6 weeks. Before return to sea level
for competition, a week or so of backed-off training is recommended to absorb
the hard training. This may not be
necessary if hard workouts are done at low altitude.
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