Effects of Altitude Training on Running Performance
A Review for Elite Athletes and Coaches
Stephanie Eyler
Spring 2005
A paper for Sports Illustrated and ESPN magazine
For years, athletes, coaches and the general public have believed that training at
higher altitude will cause improved athletic performance upon return to sea level. This
training technique has been an essential practice of many athletic teams, especially elite
teams trying to gain the extra edge over the competition. Despite this widely believed
altitude training method, studies have been performed that found training at higher
altitudes does not achieve differing performance results than training at low. Several
studies have even shown that optimum performance results may be accomplished through
low altitude training. With such differing opinions on athletic altitude training it is vital
for the public, especially elite athletes and coaches, to explore all sides of the issue to
determine the ultimate training technique.
There are several factors measured throughout the studies involved in determining
if training at higher altitude improves running performance on return to sea level. In
order to understand the results and the magnitude of the findings, the reader needs to
understand altitude, acclimatization, maximal oxygen uptake (VO2max), hemoglobin
concentration, blood lactate, red cell mass volume, erythropoietin concentration (Epo),
and buffer capacity.
Altitude
1
At altitude, atmospheric pressure is lower than normal (760 mmHg at sea level).
Proportion of oxygen and nitrogen molecules remain the same under all altitudes,
however the partial pressure of each will decrease at increasing altitude. The partial
pressure is important because blood hemoglobin is best saturated with oxygen at higher
partial pressures. Therefore, since altitude creates lower partial pressure of oxygen,
hemoglobin is not fully saturated with oxygen.
Acclimatization
The physiological adaptations of the body to changes in altitude. The time taken for
these physiological changes can vary among different people; however, in general it takes
about ten days to acclimatize 80%, and six weeks to almost fully acclimatize (Ruble).
During acclimatization red blood cell production increases, as well as the number of
capillaries within the tissues. Blood viscosity (thickness) increases, creating higher
resistance to blood flow, thus causing the heart to work harder (Sherwood).
Acclimatization is believed to improve oxygen transport to muscles (Faulkner et al.,
Levine and Gundersen, Saunders et al.)
Maximal Oxygen Uptake VO2max
Maximum volume of oxygen a person uses per minute to create energy. Indicates
capacity of body to supply oxygen to tissues. The best predictor of a person’s work
capacity (Sherwood).
Hemoglobin Concentration
Hemoglobin is the iron containing pigment of red blood cells, which is responsible for
obtaining and carrying oxygen molecules received from breathing. The hemoglobin
delivers the oxygen to tissues, where it is then used to create energy. Under altitude
2
conditions, hemoglobin is not fully saturated. In order raise available oxygen levels to
healthier amounts, the concentration of hemoglobin increases. Hemoglobin can also
carry carbon dioxide and H+ ions, both of which are acidic components; therefore, blood
acidity can affect oxygen content of hemoglobin.
Blood Lactate
Lactic acid accumulates in blood in response to exercise. Lactic acid dissociates to create
H+ ions, which increases the pH of the blood. As previously mentioned, blood acidity
can affect oxygen content of hemoglobin. Lactic acid also creates muscle soreness and
muscle fatigue.
Red Cell Mass Volume
Blood consists of plasma, red and white blood cells, and platelets. Production increases
30% at altitude, compared to sea level production (Reynafarje). Red blood cells contain
hemoglobin, which, as previously mentioned is responsible for retrieving and
transporting oxygen to tissues. Increased red cell mass volume indicates higher levels of
hemoglobin, thus more oxygen capacity.
Erythropoietin
Hormone released from kidneys to stimulate production of red blood cells from bone
marrow. Produced in response to decreased levels of oxygen in body tissue. Production
is three times higher at altitude than at sea level (Reynafarje).
Buffer Capacity
Hemoglobin buffer system absorbs H+ ions produced from working muscles. Without
buffers H+ ions will accumulate, increasing the pH of the blood. As previously
mentioned, increase of blood pH can affect oxygen content of hemoglobin.
3
Now that measured factors have been explained, studies can be examined to
determine if training at altitude will improve running performance at sea level. Actual
measures of running performance upon return to sea level and changes in VO2max will
indicate the answer. Furthermore, the other measured variables will aid in the
explanation of mechanisms for the reached conclusion.
Several studies directly tested the changes in running performance on return
arrival to sea level after training regimens at higher altitudes and on completion of
training at lower altitude or sea level. The following figure (Figure 1) presents
conflicting results of several studies; some reveal that higher altitude training improves
running performance at sea level, several indicate that low altitude training obtains best
performance results upon return to sea level, and a couple suggest no difference between
the outcomes of moderate and low altitude training on performance at sea level. Since
studies do not test at the exact same altitude ranges have been designated to differentiate
between low, moderate and high altitudes: 3000 m and higher is considered high altitude,
2200-2999 m is moderate altitude, and 0-2199 is low altitude.
HIGHER ALTITUDE
TRAINING IMPROVES
RUNNING
PERFORMANCE
Faulkner et
al.
LOWER ALTITUDE
TRAINING IMPROVES
RUNNING
PERFORMANCE
After return
Saunders et
to sea-level,
al.
time trial
performances
of all the
subjects
improved
compared to
prealtitude
control
values.
Training at low
altitude (but
also living at
moderate
altitude)
improved
running
performance in
distance
runners
NO DIFFERENCE IN
RUNNING
PERFORMANCE
AFTER ALTITUDE
TRAINING
Adams et
No
al.
enhancing
effect of
hard
endurance
training at
altitude on
performance
time
4
HIGHER ALTITUDE
TRAINING IMPROVES
RUNNING
PERFORMANCE
Burtscher
et al.
LOWER ALTITUDE
TRAINING IMPROVES
RUNNING
PERFORMANCE
Exercise
Nummela
performance and Rusko
improved:
-from 1 week
before to 3
days after
training at
altitude
-from 3 days
after to 16
days after
training at
altitude
Chapman et
al.
StrayGundersen
et al.
Levine and
StrayGundersen
400 m
performance
improved after
living in
normobaric
hypoxia
(simulated
altitude) and
training at sea
level
NO DIFFERENCE IN
RUNNING
PERFORMANCE
AFTER ALTITUDE
TRAINING
Buskirk et Performance
al.
times were
similar on
return from
altitude
training to
what they
were before
going to
altitude.
Significant
improvement in
5000m running
performance
after living at
high altitude
and training at
low altitude
Acclimatization
to moderate
altitude while
training at high
intensity at low
altitude
improves sea
level endurance
performance
5 km time trial
improved by
moderate
altitude
acclimatization
and low
altitude training
Figure 1: Results supporting enhancement of running performance from high altitude and low altitude, and
finding no effect. Adams et al. study trained at moderate altitude, Burskirk et al. study trained at high
altitude.
5
HIGHER ALTITUDE TRAINING IMPROVES RUNNING PERFORMANCE
Two studies have demonstrated that after training at higher altitude more
improvement in running performance can be achieved at sea level. Faulkner et al. timed
the running performance at sea level of five well-conditioned men after they trained for
three weeks at moderate altitude. Time trials of one and two mile runs at sea level after
altitude training were significantly decreased from pre-altitude training times; times were
decreased on average by 29 seconds for the mile and one minute and 11 seconds for two
miles, while the controls decreased only an average of 18 seconds for the mile and 46
second average for the two mile. Keep in mind that though the control subjects
demonstrated an improvement in time, they did not train at altitude; thus their
improvement is due to actual training and practice. The results of this study, however,
are weakened by the fact that only five subjects were tested. This low subject number
may effect the actual results applying to the general population, and therefore cannot be
heavily relied upon to support that training at altitude will improve running performance
in elite athletes upon return to sea level.
Burtscher et al. obtained similar improvement in performance upon return to sea
level. A group of ten amateur males trained for 12 days at moderate altitude and had total
work capacity measured the week before altitude training, and three and 16 days after
altitude training. Total work capacity indicates the maximum amount of force produced
over a certain distance, and in this study was found to increase 16 percent by day 16 after
altitude. The control group, however, only increased a total of eight percent by day 16.
Since the subjects tested after altitude training enhanced TWC, that means more muscle
fibers were recruited for the activity, thus the activity was performed faster. Despite
6
these supportive results indicating training at altitude can improve running performance,
two flaws of the study decrease its validity. Most importantly is the fact that amateur
subjects were tested. These subjects entered the study at low levels of athletic ability,
thus training of any kind would enhance running performance; it cannot be assumed that
altitude is the causing factor. Also, the study does not directly measure times of running
performance. Though enhanced total work capacity occurred, specific time differences
cannot be determined from the percent change in TWC. Both these factors combine to
weaken the total validity of the study in regards to our purpose.
NO DIFFERENCE IN RUNNING PERFORMANCE AFTER ALTITUDE
TRAINING
Conclusions are not always met in all studies indicating which altitude training
creates optimal running performance upon return to sea level. These inconclusive studies
further contribute to this already unresolved issue. The Burskirk et al. study concluded no
improved post-high-altitude performance out of any of the six tested runners. Though
only six subjects were tested, the subjects were trained at altitude for over 60 days. Such
a large amount of time, gives each body plenty of time to acclimatize to the altitude,
therefore all physiological changes were able to occur. Considering the length of the
training, the study provides convincing results indicating that training at altitude has no
added effect on running performance. Another study found results in favor of sea level
training. The control group (training at sea level) improved running performance time by
7 seconds, while the group training at moderate altitude increased time by 7 seconds
(Adams et al.). Similar to the Burskirk et al. study, the Adams et al. study trained at
altitude for appropriate for complete acclimatization, and even increased the number of
7
subjects to 12. As opposed to earlier studies with only six and ten subjects, even slight
increase in subject number can increase the validity and applicability of results.
LOWER ALTITUDE TRAINING IMPROVES RUNNING PERFORMANCE
Several studies have found that training at a low altitude improves running
performance, many of which contained methods creating the most valid results. Levine
and Stray-Gundersen tested thirty nine distance runners in various conditions: living and
training at moderate altitude, living at moderate altitude and training at low altitude, and
living and training at low altitude. After training at altitude levels for four weeks it was
determined that the second group that lived at moderate, but trained at low altitude
achieved improvement in running performance by an average of 13.4 seconds, while the
other groups found an increase in time trials by up to an average 26.7 seconds in the low
altitude (control) group. Similar study techniques were applied in the Saunders et al.
study, which tested 22 elite male middle and long distance runners. This study observed
personal best running times a month after training in all the subjects the lived at moderate
altitude and trained at low altitude, but only three of the 13 subjects achieved personal
best out of the living and training low altitude group. Both of these studies were
performed on numbers of subjects well exceeding any study in support of altitude
training enhancing running performance. With 39 and 22 subjects tested, also over long
periods of time for full acclimatization, results can be accurately applied to the elite
athlete population.
An additional study on well-trained distance runners discovered similar results. A
reduction of an average of 5.8 seconds in running performance after altitude training was
8
seen in the group living at moderate altitude and training at low altitude, while the
opposing control group (living and training at low altitude) had widely variable results
among the subjects, including as much as an 18 second increase in time (Stray-Gundersen
et al.). This study contains valuable findings indicating low altitude training generate
optimal running performance, however keep in mind that a group was not tested for
training at altitude. This makes it difficult to apply to this review’s purpose; however, it
gives light to a different approach to optimal training technique.
Nummela and Rusko also looked into training athletes at low altitude after living
at moderate altitude. The 18 well-trained sprinters were split into a group of eight living
moderate altitude (in an altitude house) and training low, and ten as a control group at sea
level. At the conclusion of the ten day testing, results illustrated all runners that lived at
moderate altitude but trained at low altitude improved running times after return to sea
level by an average of 0.42 seconds. No changes were seen in the control group. Keep in
mind that, though, 0.42 seconds may seem a very minimal improvement, for competitive
athletes, even the slightest improvement can place them over their opponents. This study
introduces an approach different from previously explained studies; the use of an altitude
house. This “altitude house” created an environment known as normobaric hypoxia, or a
house of normal pressure but with less oxygen. Results are slightly weakened due to the
fact that pressure remains the same as normal sea level conditions; however, the fact that
less oxygen was available still holds importance. It is the lack of oxygen molecules that
create most physiological changes during acclimatization; therefore, results may still be
lightly applied to this review’s issue.
9
Figure 2 graphically presents the changes in running performance times from
several of the above explained studies. Obviously, the issue is not completely resolved
since both low and moderate altitude training has shown to decrease performance times.
However, moderate altitude training also was found to increase time. With the
weaknesses and strengths explained for the previous studies, it seems most logical to
conclude that training at altitude does not create optimal running performance.
Effects of Altitude Training on Running Performance at Sea Level
20
10
Change in Running Performance (seconds)
0
low
moderate
-10
-20
Levine and Stray-Gundersen
Stray-Gundersen et al.
Nummela and Rusko
Faulkner et al.
Faulkner et al.
Burskirk et al.
-30
-40
-50
-60
-70
-80
Altitude Training
Figure 2: Effects of Altitude Training on Running Performance at Sea Level. Low Altitude=0-2199 m,
Moderate Altitude=2200-2999 m. All studies graphed show results from well-conditioned or elite athletes.
Negative values represent improved running performance time; positive values are added time to prealtitude running times.
Aside from time trial measurements, VO2max is another major measured variable
which indirectly indicate changes in running performance. VO2max increases cause the
increase of oxygen molecules in tissues to create a higher rate of energy production
through oxidative pathways. If the body creates more energy, then it is obvious that
10
athletic performance will be enhanced. The issue now converts to if altitude training will
increase VO2max, which indirectly can help to answer our original question whether
altitude training improves running performance. After reviewing several studies, this
issue still proves to be unresolved. Several studies have shown that low, moderate and
high altitude training can increase VO2max, while one other study has shown a decrease
from moderate. The following figure (Figure 3) illustrates results from these conflicting
studies.
Change in Maximal Oxygen Uptake from Altitude Training
10
Percent change in maximal oxygen uptake
8
6
Levine and Stray-Gundersen
Saunders et al.
Stray-Gundersen et al.
Burskirk et al.
Chapman et al.
Dill and Adams
Faulkner et al.
Adams et al.
4
2
0
low
moderate
high
-2
-4
Altitude
Figure 3: Change in Maximal Oxygen Uptake (VO2max) from Altitude Training. Low altitude=0-2199 m,
Moderate altitude=2200-2999 m, High altitude=3000+m. There are no visible bars for Adams et al. study
because the study found no changes in VO2max in either low or moderate altitude training.
Most of the studies, except one, presented in figure 3 indicate that altitude training
will improve VO2max. The Saunders et al. study discovered that altitude training did not
increase VO2max, which indicate that altitude training will not indirectly improve running
performance. VO2max after training at moderate altitude decreased 3.3 percent from pre11
altitude levels in ten elite male middle and distance runners. No changes in VO2max were
found in Adams et al.’s study.
The remaining six studies demonstrated ranges from three percent to nine percent
increases in VO2max. Though there is one conflicting and one inconclusive study, one may
deduce that in most cases VO2max will increase after altitude training. The figure also
indicates that perhaps moderate altitude creates optimal results compared to low and high
altitude training. Even though this conclusion can be reached from the graph, keep in
mind that VO2max is only an indicator of running performance; it is only one key factor in
running performance (Fallowfield). This is obvious since this article previously found
that running performance improved more at low altitude training.
There are several studies indicating higher altitude training will improve running
performance upon return to sea level, the Faulkner et al. study, the Burtscher et al. study,
and even perhaps the six studies illustrating increased VO2max in figure 3. However, these
studies have been previously scrutinized for limited number of tested subjects, training
time, and slightly overreaching assumptions. Such limitations of the studies and results
indicate a weaker argument supporting major beneficial results to altitude training.
Numerous findings do oppose the general public’s assumption that higher altitude
training improves running performance upon return to sea level. As mentioned in figure
1, five studies found that low altitude training enhanced running performance at sea level.
Many of these studies tested several subjects, as opposed to the Faulkner et al. and
Burtscher et al. studies, which only tested five and ten people, respectively. Therefore,
the studies convincingly indicate that higher altitude does not necessarily improve
running performance at sea level.
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Furthermore, it has been introduced that perhaps living at high altitude but
training at low altitude will create optimal performance at sea level. How can this occur?
As previously mentioned, acclimatization is believed to improve oxygen transport to
muscles. This improved transport occurs due to increased VO2max, erythropoietin
production, red cell mass, hemoglobin concentration, buffer capacity and decreased blood
lactate. Since these physiological changes facilitate the transport of oxygen to the
muscles, more energy is created in the muscle. So if acclimatization can create these
positive effects for athletes, how does altitude training affect the ultimate improvement in
running performance? High altitude training is known to decrease athletic capacity
because maximal aerobic power decreases about 1% for every 100 meters above 1,500 m
(Levine and Stray-Gundersen). If elite athletes are training at a lower capacity than
normally possible, their training will not necessarily improve or even maintain the
athlete’s competitive fitness. As mentioned previously, every split second is of utmost
importance in the world of elite sports. If these athletes choose to train at a level below
maximum capability they will not maintain or improve performance compared to those
placing 100% into training at lower altitudes.
In a society that places sports in the spotlight, athletes and coaches are constantly
trying to find the ways to create the winning team. This review has illustrates that despite
popular belief, higher altitude training does not create optimum running performance at
sea level; perhaps the answer is in low altitude training. However, acclimatization has
also become focus for optimal training methods. Elite athletes and coaches should
seriously consider researching more about the live high train low theory in order to gain
an extra edge over the competition.
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