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Responses and Comments Physiology/Science<
May 29, 1997
Question:
Thank you for sharing the expedition with us! We are all
looking forward to a safe and successful outcome, both in
terms of the summit and your findings. A few years ago, I
did some research on the effects of Acetazolamide on max and
submax exercise at normoxic and hypoxic conditions. It was
the treatment of choice at the time for AMS. Can you tell me
why Nifedipine is now the preferred treatment? How long does
it take to reach therapeutic levels? One of the potentially
negative side affects of Nifedipine is periferal edema, and
it is contraindicated in cases of CHF. Is periferal edema a
problem in climbers on Nifedipine? Is it used to treat
already existant HAPE or merely to prevent it? Thanks again
for this exciting venture!
Barb Engebretsen
Laurel, NE
Response from Dr. Howard Donner:
Acetazolamide is still the "treatment of choice" for AMS and
prevention of AMS. Nifedipine is considered the drug of
choice for HAPE (High Altitude Pulmonary Edema) especially
when lacking the availability of supplemental oxygen.
Therapeutic levels of Nifedipine are reached very quickly
especially when initiated with a 10mg bite and swallow dose.
This can be followed by the 30mg sustained release form once
or twice a day. Peripheral Edema is not typically seen with
Nifedipine administration at altitude (unless pre-existing),
because cardiac function in HAPE patients is usually quite
normal. The biggest clinical side effect would be
orthostatic hypotension, but this is rarely seen in hydrated
climbers. Nifedipine has been used for both treatment and
prevention of HAPE.
Question:
I find your medical information of sats and vitals to be
quite interesting. When climbing, what flow of O2
do you use and what are the sats and vitals with activity?
Do you ever consider high dose steroid injections (decedron)
in times of distress? Also, how about the use of free
radical inhibitors or carbonic anhydrase inhibitors?
Scott Hardeman
St. Louis, MO
Response from Dr. Howard Donner:
The flow rate is set at 2 liters per minute. As an example,
during a test, David Breashears' oxygen saturation at 21,400
feet was 94% on 2 liters per minute. Our climbers usually do
not use bottled oxygen until they are above 26,000 feet.
Decadron is used along with descent for cerebral forms of
severe mountain sickness. Carbonic anhydrase inhibitors
(Diamox) are often used for prevention and or treatment of
AMS (acute Mountain Sickness). Our climbers prefer to
acclimatize at a rate which avoids symptoms without the use
of pharmaceutical agents.
Question:
Greetings Howard,
It's been a while since we've spoken. I have enjoyed your
responses to the previously posted questions. Knowing how
you love a challenge, my questions are: "what is the one
question about altitude that has given you the most
difficulty in answering? And, what steps are you taking
towards figuring it out?"
Your friend,
Jimmy Rosen
Durham, NC
Response from Dr. Howard Donner:
Hey Jimmy, how's pre-med? Thanks for writing. Probably of
most interest to me is the path of physiology of simple AMS,
i.e. what causes the headache, anorexia, and malaise. The
most lucid hypothesis is reviewed in a journal article by
John Krasney entitled "A neurogenic basis for acute altitude
illness" from
Medicine and Science in Sports and Exercise 1994:26
(2) 195-208. Please give me a call when I am home (mid-June)
and we can talk more about this—work needing to be
done.
Question:
I would appreciate if you could post this question for me,
as my internet mail service does not work properly. Has
anyone attempted to modify an oxygen rebreather system for
use in mountain climbing? It seems that oxygen is often a
limiting factor in an ascent of Everest, and the rebreather
would provide a long-lasting oxygen source at nearly body
temperature. Also, does any team member have any
recommendations for books about Everest? Hope the weather
improves. Best of luck.
Steven B. Bird, M.D.
Pensacola, FL
Response from Dr. Howard Donner:
Since the 1950's climbers have experimented with rebreathing
systems on Everest. From an informal survey at Base Camp, it
seems that these systems have been fraught with problems
primarily associated with freezing. I am aware that there
are current generation rebreathing systems for marine use
that are very compact and efficient. I am not aware of any
field testing of these units as of yet.
Response from David Breashears:
Some of the best Everest books are: West Ridge by
Thomas Hornbein, Everest by Peter Gillman (photo and
editorial analogy), Everest by Walt Unsworth
(chronological history),
Everest: The Mystery of Mallory and Irvine by Tom
Holzel and Audrey Salkeld, Everest the Hard Way by
Chris Bonnington.
Question:
This is a two part question.
1. I have read some literature that indicates that women are
less susceptible to HAPE than men because their blood
doesn't "sludge" as much. Is this true? And if so, why? What
are the medical-anthropological implications of this?
2. David Breashears, according to interviews, Krakauer's
book, and a recent ABC special, has been very critical of
the traffic of climbers and "clients" descending (or rather
ascending) upon Everest. Could it be that your team, even in
the name of science, is promoting exactly the wrong message?
It is common knowledge that Everest is horribly polluted,
and becoming a geographical cure for anyone with enough
money and chutzpah. (It seems that climbing Everest does
have some long range neurological implications—the
loss of common sense, as I see that Anytoyli Bokureev &
Breashears are back even after the ridiculous loss of life
last year.) I *do* wish you all a safe climb. I see that the
mountain has already claimed many lives this year as well.
Treat her well.
Allegra Blake
Michigan
Response from Dr. Howard Donner:
Although I have heard anecdotes about this, I do not know of
any research that supports this idea.
Response from David Breashears:
How could our team be promoting the wrong message if 1) it
is only a two-person climbing/filming team versus the
average 10-person team; 2) if our purpose for being here is
to study the effects of high altitude on the body and brain
so we might know more when we (and hopefully other climbers)
climb high in the future? To date, none of us on our team
(with a combined 26 years of Everest climbing) has been
diagnosed with any neurological problems or lack of common
sense. Furthermore our combined seven successful summits
shows that we may have an excess of common sense. If the
increased traffic brought with it experienced Himalayan
veterans all would be okay. It is the influx of
inexperienced climbers on Everest that brings with it the
problems.
Question:
To Pete;
Hello my fellow Coloradoen, and congratulations on your
success. While I climb fourtneeres here I will be thinking
of you and your team, and hope to do Everest someday. My
questions is, when I am mountaineering I lose my appetite
and have to force myself to eat, do you guys run into that
problem? And second, when you are at high camps and near the
summit, are you cooking meals or do you eat things like
energy bars to conserve the weight of food, stove, fuel?
Good luck, and I look forward to hearing you speak about
your trip when you get back to Colo.
Scott McCune
Colorado Springs, CO
Response from Pete Athans:
Dear Scott,
Thanks for your kind message. Altitude and appetite have an
inversely proportional relationship. In Base Camp, we have
cooked meals prepared, but by the time we get to Camp III
and IV, we are reduced to eating snack food and soup. Good
climbing.
Question:
During climbs in my local mountains to about 10,000 feet, I
have noticed that my hands and feet swell quite a bit, and
can cause my boots to become very uncomfortable. When
climbing at extreme altitude, is such swelling a factor? If
so, do you have a means to control it? Best wishes to all of
you. My thoughts and energies are with you.
Dirk Petchul
Orange, CA
Response from Dr. Howard Donner:
There are many reasons for swelling at altitude. At any
altitude, especially in the heat, swelling of the hands and
arms may occur due to centripetal force of the swinging arms
or lymphatic and venous constriction from pack strap
compression over the shoulder. At altitude, peripheral edema
may occur in some individuals (studies have shown peripheral
edema to be more common in women). Peripheral edema at
altitude may be benign or may be associated with other
symptoms of AMS (Acute Mountain Sickness).
Treatment for peripheral edema involves either resting at
the same altitude or very small doses of diuretics which
speeds up resolution. I usually don't put patients on
diuretics when they are climbing.
Question:
Hi, We read your newsflashes every day! We were wondering
what the boiling point of water is at Base Camp and at the
higher camps? We looked it up and found that Everest Base
Camp has an atmospheric pressure of about half that at sea
level which significantly decreases boiling point. Can you
put your hand in boiling water at Camp III and IV? We
climbed Mt. Adams in Washington a few years ago and noticed
that even at 8000 ft. our pasta had a real hard time getting
soft. Do you use pressure cookers or do you live with
crunchy pasta?
Good luck!
Charles Balogh
Portland, OR
Response from Dr. Howard Donner:
It is possible to grab something from boiling water, but if
you leave you hand in the water you will definitely get
burned. The boiling point at Base Camp is 175 degrees
Fahrenheit (212 degrees at sea level). At Base Camp we use
pressure cookers to cook pasta and rice which cuts the
cooking time in half. The climbers use pressure cookers on
the mountain at Camp II.
Question:
Howard Donner MD,
Greetings from those of us who remain sanely at sea level.
Are there physiology experiments other than the neurological
testing going on up there? What kinds of diagnostic
equipment do you have at Base Camp? If you could have only
one piece (excluding a stethoscope) what would it be? Do any
of these incredibly buffed individuals (including yourself,
of course) ever get anginal type chest pain? Have any/all of
these folks ever had a cardiac echo? Would any of these
folks LIKE a cardiac echo? (I'll spring for the tape). How
on earth did you get this gig? Stay safe, warm and
reasonably well O2
saturated.
Susan J.Alexander, MD
San Francisco, CA
Response from Dr. Howard Donner:
We are looking at limited physiologic parameters including
oximetry and respiratory rate all the way to the summit. Our
main focus is on the psychometric tests. At Base Camp we
have access to limited equipment: a pulse oximetry, oto and
opthalmoscope, stethoscope and thermometer. If I had to
choose only one piece it would be the oximeter—it's a
good tool to determine response to oxygen (i.e. guess-timate
degree of shunt). There have been case reports of anginal in
trekkers, however; I have never heard of an episode of
angina in a Himalayan climber. As you know, I always carry
Nitrostat SL, Transdermal Nitro Patches, a Beta-blocker, and
a highly sophisticated drug called aspirin. There have been
a number of studies looking at cardiac function at altitude,
including extensive echo cardiography at Operation Everest
II (OEII) in Natick, MA in 1985. Amongst others, Dr. Ben
Levine, a cardiologist in Austin, TX has been highly
involved with echo cardiography as well.
Question:
Hello there on the top of the world. My question is
concerning the
newsflash that was posted on May 9, 1997.
The Sherpa that was treated for HAPE by using a make shift
hyperbaric {Gamon Bay}, I was wondering if you could explain
how it might be different with the current chambers found at
hospitals or flight treatment centers? Also, what kind of
depths due you take the patients down to.
Take care and God's speed,
Richard N. Lawson, BS, CCP
Springfield, IL
Response from Dr. Howard Donner:
The portable, fabric hyperbaric chambers that we use are
pressurized to relatively low pressures (i.e. 2 PSI),
compared with rigid hyperbaric chambers found at medical
institutions. Ascent to the summit of Everest reduces the
atmospheric pressure by approximately two thirds. Diving to
only 20 feet below the ocean increases the pressure by the
same amount. As you can see the pressures used for
recompressing diving injuries are orders of magnitude
higher.
Question:
Hope all is going well! I am very interested if any blood
gas studies will be made. Is anyone on the team on any type
of medication—vitamins or prescribed medication? Why
are no women on the climb? Take care.
Betsy Tingler
Ruther Glen, VA
Response from Base Camp:
There are no blood gas studies being made on this
expedition. We are conducting neuro-behavioral tests with
our climbers along with taking pulse oximeter readings at
various altitudes. There are no women climbing, but we do
have a female Co-Producer and Associate Producer at Base
Camp.
Question:
Do your lungs have a burning sensation all the time because
of the air pressure? How far can you climb without a major
rest? Is the wind constant? Or does it come in bursts? How
do you keep the tents in the ice without blowing away? Good
luck and we are all watching your climb.
George Wild
Montvale, NJ
Response from Pete Athans:
We do not experience any burning sensation. We usually rest
about 10 minutes per each hour of activity. Wind is
variable. The tents are attached to ice with ice screws or
snow pickets.
Question:
To David Carter, I was wondering if any climbers have ever
tried taking a blood transfusion before their summit
attempt, to see if that would help deliver more oxygen to
the brain during the climb?
Good luck,
Dave Roberts
Greenfield, IN
P.S. Maybe we could climb Red River Gorge sometime.
Response from Dr. Howard Donner:
At altitude, it is not simply a matter of oxygen carrying
capacity (the amount of red blood cells), but rather how
efficiently oxygen can be delivered to the necessary tissues
including the brain, heart, lungs and muscles. With
increasing red blood cells ("hematocrit"), blood viscosity
can increase to the point where profusion (or delivery) is
impaired. On ascent to altitude hematocrit goes up almost
immediately due to mild dehydration, i.e. an increasing the
concentration of red cells. Within weeks new red blood cells
are produced at altitude at a rate that the body can use
efficiently. In 1983, climbing scientists on Everest
attempted to remove red blood cells, and found no change in
their performance.
Question:
What effect does high altitude have on metabolism? Is the
extreme cold also a factor? What changes in weight can be
expected as a result, especially at Camp IV and above?
W.L.
Kansas
Response from Dr. Howard Donner:
Metabolism is a very broad term. Initially on ascent, there
is an increase in adrenaline-like compounds which increase
metabolic rate and result in increases in blood pressure and
heart rate. The body also attempts to become more efficient
by increasing mitochondrial density and increasing oxidative
enzymes (enzymes involved in metabolism). Mitochondria are
the power factories for human cells. Interestingly, actual
metabolic depression of membrane Na+/K+ ATPase, in the
brain, is not seen at levels of hypoxia typically
encountered in climbers. This means that the brain remains
normal from an energetics (metabolic) standpoint. If by
metabolism you mean performance, VO2
Max (maximal oxygen uptake) has been shown to decrease
steadily with increases in altitude. The extreme cold
requires greater caloric intake to maintain normal body
temperature, and at altitude climbers feel they have more
trouble staying warm. The amount of weight loss seen in
climbers at Mt. Everest is variable. Our climbers often lose
little weight. Historically, Everest climbers have lost up
to 40 lbs or more on a single expedition. Climbers arriving
with less excess body fat tend to lose less body fat.
Question:
Much of this climb is focusing on the affects on the mind
and body at high altitude. How does your body feel when you
return home (assuming "home" is somewhere around sea level)
after a long period of time at very high altitude? Do you
feel super human with all those extra red blood cells? Do
you find that your resting heart rates are even lower than
they were before you began your climb? And emotionally, do
you find that you suffer something akin to separation
anxiety or post-partum depression?
Thank you and best wishes for a safe and successful
expedition.
Larry Buttrey
Long Beach, CA
Response from David Carter:
When I return from an expedition, I have lost so much weight
while living at high altitude that I sleep for a couple of
weeks. I usually don't feel like doing any exercise for at
least a month—much of that is due to mental
exhaustion.
Question:
I have been in contact with Dr. Peter Hackett who referred
me to this page in regards to my senior project. I am
studying the effects of altitude on myself and two partners
during a three week climb of Denali's West Buttress. I will
be monitoring for cognitive, sensory, and motor deficits.
During my extensive literature review finding specific
examples of the types of tests administered by other
investigators has been quite difficult. So far one of the
most helpful resources has been this page and the tests
posted on it and created by Gail Rosenbaum. I was hoping
that one of the investigators might be able to offer
assistance in finding more tests like the ones posted here.
Specifically the Stroop test, Verbal Puzzles, and
Remembering Sentences. My goal is to find enough of these
tests to collect data twice daily on three people for three
weeks. I am also interested in where I might find an
oximeter to measure pulse rate and oxygen saturation, as
well as how to measure lung size and capacity. Is lung
capacity the same as forced vital capacity? And would a
spirometer be the instrument to measure it? What is peak
expiratory flow? Are you measuring finger-tapping speed? If
so how? Is the Automated Performance Test System (APTS)
being administered and do you know where the software can be
found? How is HVR measured?
I appreciate any help you may be able to offer. Anything
will surely be of help, especially considering I leave May
30th for the climb.
Thanks, and Climb On!!
Greg Barrett
Anchorage, Alaska
Response from Dr. Howard Donner:
A good source for lightweight pulse oximeters is Chinook
Medical Gear Inc. (970-328-2100) in Eagle, Colorado.
For the neurological tests the following papers will be of
assistance:
"The Cost To The Central Nervous System Of Climbing To
Extremely High Altitude," Tf. Hornbein,
"Do Climbs To Extreme Altitudes Persistent Memory Impairment
After High Altitude Climbing," G. Cavaletti,
"Brain Damage After High-Altitude Climbs Without Oxygen," G.
Cavaletti,
"Long-Lasting Neuropsychological Changes After A Single High
Altitude Climb," G. Cavaletti,
"Neuropsychological Functioning After Prolonged High
Altitude Exposure In Mountaineering," Cf. Clark.
Question:
I have been interested in the subject of Acute High Altitude
Sickness since my brother, Edward (also a former Cheley
Camper as is Dr. Tom Hornbein), died of it during a 1976
ascent of Mt. McKinley. The weather was bad and the party
could not get him to a lower elevation. The malady seems to
strike without a great deal of predictability. The climber
can have previously gone to an elevation several times
before without incidence, and then for some reason on a
subsequent ascent to that elevation be stricken. Have you
been able to identify any precursors that might signal its
onset or any predisposing factors? Is there a threshold
elevation where it presents itself and an elevation above
which it seems to be of little problem? What precautions
have the team taken to avoid it and why was it believed that
this course of action would prevent the onset? If that has
not been totally successful in avoiding High Altitude
Sickness, what would you have done differently? Who has had
it, at what elevations?
Jim Guleke
Austin, TX
Response from Dr. Howard Donner:
Interestingly there have been numerous recent observations
that climbers with preexisting upper respiratory infections
(often viral) are predisposed to HAPE (High Altitude
Pulmonary Edema). This may explain some cases of seemingly
random HAPE in individuals whose prior climbing history
suggested no predisposition.
Climbers often report the unexpected onset of HAPE. With
closer scrutiny of the ascent profile there are often subtle
changes from one climb to the next. An extra staging or rest
day at the same altitude can influence the potential for
development of HAPE. Some have conjectured that other
variables including diet (ie, salt intake) may cause changes
in susceptibility but this has been poorly studied.
Additionally, the use of pharmaceutical agents, such as
nifedipine, may be used to prevent HAPE in known
susceptibles.
There is no elevation above which HAPE is no longer a
potential danger.
The best indication that our team can avoid complications
with HAPE is a clear history of no prior problems. With the
human body, there are never guarantees but a pristine prior
history is extremely reassuring.
Question:
Greetings from Washington- the monsoon has decided to visit
us before it goes on to Asia- lots and lots of rain. I hope
your weather conditions are better. My question is how does
the altitude affect your senses like smell, taste, hearing
and seeing? Are they dulled or enhanced the higher you go?
How about your sense of balance- do you experience vertigo?
Thank you and best of luck for a safe summit day.
Colleen Merrill
Langley, WA
Response from Dr. Howard Donner:
Smell and taste are definitely diminished at base camp
(17,600') and at the higher camps. The return of these
senses is best appreciated upon descent to lower elevations.
With symptoms of AMS (Acute Mountain Sickness) balance can
be affected, however, in a well acclimatized climber balance
should be normal. At extreme altitudes, climbers suffering
from chronic hypoxemia (low blood oxygen) have described
difficulty with balance. Other factors that affect climbers'
balance include dehydration, hypoglycemia and exhaustion.
Question:
My Physical Science and Astronomy students would like to
know if any of you were particularly interested in science
when you were in 8th grade. Some of them don't think science
has any practical applications to every day life. How has it
helped you out in the area of physics? Good luck and thank
you.
Marg Freeman
Boise, Idaho
Response from Ed Viesturs
I'm a veterinarian and am intrigued by physiology. Climbing
and exercise physiology go hand in hand.
Question:
I am a first year medical student at the Univ. of
Massachusetts Medical Center. I would like to know if any of
the four climbers have ever had any episodes of HAPE or HACE
on any previous climbs? Also are you planning on publishing
any of your results? I plan on doing research in high
altitude physiology and I will be following this research
expedition with much interest. Good luck.
Michael Todd
Millbury, MA
Response from Dr. Howard Donner:
All of the climbers have had symptoms of acute mountain
sickness at one time or another including: lethargy, lack of
appetite, headaches, and sleeplessness. None of the climbers
have ever developed severe forms of mountain sickness such
as full blown HAPE or HACE.
The results of this study will eventually be published. Dr.
Tom Hornbein at the University of Washington will be able to
offer you more specific information on upcoming publication
of this data.
Question:
I am interested in whether you are testing the Sherpas
during your climb - 1. to see how their test results would
compare to your results and 2. to help understand how their
bodies handle the high altitude stresses. Are they adversely
affected by going down to sea level like we are by going up
so high? Best of luck!
Betsey LeBreche
Del Mar, CA
Response from Dr. Howard Donner:
Yes, our sirdar Jangbu Sherpa will be tested along with the
other climbers. Interestingly, there has never been any
indication of a "low altitude" sickness in high altitude
natives descending to lower altitudes. I have often heard
local Sherpas speak of "low altitude" illness in yaks that
typically inhabit regions of the Khumbu above 14,000 feet.
However, many yaks live in low altitude zoos around the
world. The illness that the yaks developed when descending
to low altitude is probably due to exposure to numerous
infectious diseases transmitted by lowland cattle to which
the yaks have not developed immunity.
Question:
Many mountaineers take prescription drugs to help negate the
affects of altitude. This practice seems most common in
areas where climbers ascend from low elevations quickly and
have little time to acclimate. Is the use of any type of
medication the standard on Everest? We are with you in
spirit.
Kerry, Jodi, Mike, & Kip Hanson
Shorewood, WI
Response from Dr. Howard Donner:
Most climbers on 8000-meter peaks prefer to acclimitize
without the use of prescription drugs, when possible.
However, the climbers generally carry a number of high
altitude prescription drugs for use in emergencies. These
drugs include: Nifedipine for High Altitude Pulmonary Edema
(HAPE), Decadron for High Altitude Cerebral Edema (HACE) and
Diamox. Even in an acclimitized climber, Diamox is often
used in very small doses prior to bedtime to decrease or
eliminate periodic breathing. This makes for a much more
restful night's sleep at extreme altitude.
Question:
To the Team: I've summited Mt. Rainier a couple of times and
know the air gets thinner the higher you get above 12,000'
My question is how much more of an effort and how much more
oxygen deprived do you get as you accent above Camp I. Is
food (fuel) carbo loading as important or more important as
breathing correctly? Thanks for your insights.
Mike Rindahl
Seattle, WA
Response from Dr. Howard Donner:
Although proper breathing can enhance air exchange, no one
is able to maintain voluntary changes in ventilation 24
hours a day. Different forms of purse-lipped breathing to
enhance expiratory positive airway pressure (EPAP) have been
tried. EPAP improves air exchange by holding open the
alveoli at the end of expiration increasing air exchange.
Although probably effective these modified breathing
patterns are impossible to maintain, especially during
sleep—a very important time for acclimitization.
There have been numerous studies looking at carbohydrate
intake at altitude. There is some suggestion that eating
foods with a lower respiratory quation (rq - a ratio that
looks at the amount of oxygen needed to metabolize food
substrate) may be beneficial, although studies have been
equivocal.
Question:
Hello to David Carter,
I grew up with you in Sylvan Ridge. I know that many
Hoosiers, myself included, are praying for your safe return.
I wondered if this climb was any easier, either mentally or
physically, because of your earlier climb on Everest? Also,
how far up the mountain are the laptops going? And, what
kind of computer equipment is there?
Nancy Johnson Heck
Carmel, Indiana
Response from David Carter:
Dear Nancy,
Yes. The climb is a lot easier because of my earlier attempt
on Everest. This time I know what to expect and it makes
things much easier for me. Mentally, I'm not as stressed as
I was in 1991. The computers live full time at Base Camp. We
are currently using two Apple Powerbook computers (one is a
1400c and the other is a 5300cs) that connect daily to our
satellite phone so that we can download all the e-mail
coming into our site. Thanks for your support.
All the best,
Dave Carter
Question:
Hi guys. Hope that everything is going well on the mountain.
My question: what is the difference in oxygen levels at the
top of the mountain from what it is at base camp? Also, how
is the team coping with the altitude sickness they must be
experiencing?
Robert & Alicia Tindall
Lexington, KY
Response:
At the summit, there is 1/3 of the oxygen available at sea
level. At Base Camp it is about half. To date, none of us
have experienced altitude sickness.
Question:
Hello and congratulations on your good progress so far. I
know that the longer you're exposed to the thin air at
altitude the more adapted you become. However, from your
past experience what determines the approximate altitude at
which you no longer can adapt and altitude sickness begins?
Climbing abilities aside, are certain individuals just more
adaptable than others or can anyone adapt given optimal
training, physical conditioning and diet? Good to luck to
you all and especially to fellow Hoosier and friend David
Carter.
Paul Kite
Response from Base Camp:
There is no ideal person yet who adapts better to altitude
than others, but there are some subtle indicators that have
been found that may aid in a person's performance at
altitude. By that same token, there are some people whose
profiles will say they won't do well, and yet they end up
performing well at altitude. Some of the indicators that we
think will aid someone at altitude (regardless of physical
training and diet) are lung size and capacity, blood oxygen
saturation, and hypoxic ventilatory response. There is some
evidence that having more intracranial space between your
brain and skull will make you less prone to headaches which
may make you more prone to acclimatizing. We generally
consider going to Camp III as the highest point one can
adapt to. We believe that a night or 2 at 24,500 (Camp III)
feet is the highest one can positively adapt to. If you're
like Ed Viesturs and want to climb without oxygen to the
summit a trip to the South Col is probably beneficial. We
have not seen any climbers, to date, who can adapt to
altitudes beyond Camp IV (26,000 feet). At this point,
humans generally deteriorate and become weakened with time.
Dr. Tom Hornbein adds:
Regarding predictors of performance, there are indeed a few
physiologic hints but when you get down to the moment of
truth, putting one foot above the other day after day, it's
what's in the head that seems to count most, that is
stubborn commitment (coupled with judgment helps). I suspect
our team will concur.
It's generally thought that the maximum altitude at which
humans can stay permanently is about that of the Everest
Base Camp. This belief is based on the simple observation
that that's the highest known habitation, namely at a mining
community in Chile. I like to think that above that
altitude, man is a transient guest. Initially the benefits
of acclimatization are dominant, so net performance
improves, but with time a process of wasting—so-called
high altitude deterioration—becomes dominant so if we
stay too high too long we begin to go downhill (figuratively
and likely literally as well). The timeline for crossover of
these two competing forces of opposite sign is hard to
define but both are probably accelerated the higher one
goes. And as the process of acclimatization becomes more
complete and slows, the process of wasting becomes
increasingly dominant.
Above 8000 m. (approximately 26,000 feet) we don't know
whether the rate of acclimatization is increased but we sure
do believe m one can linger if not thrive is measured in
hours to a few days. These impressions are based on
anecdotal experience and the climbers are that the time one
can linger if not thrive is measured in hours to a few days.
These impressions are based on anecdotal experience and our
team of climbers are living with as much of this as anyone
has.
Question:
Hello Liesl and David! Hope all that traffic on the mountain
isn't slowing your work down? How have you been managing?
We're doing our own physiology and endurance project and are
wondering if we could get the team's resting, walking around
basecamp and active pulse rates at whatever altitude it's
taken. We'd like to compare ours with yours. We'll also be
collecting data on breaths/minute at rest, walking and
active moments. Could you give us that data, too? It could
be at different times, convenient to you. Thanks. Warm hugs,
Nancy Ferguson's third graders. PS. We love your webpages
and read them almost every day.
Nancy Ferguson's Third Grade Class
Newton, MA
Response from Base Camp:
Hi to Nancy Ferguson's third grade class from Liesl and
David. Here are a few stats on our pulse rates: Our resting
pulse rates at Base Camp are around 60 - 65. Walking around
camp, our pulse rates are around 85 - 95. Working around
camp or hiking is around 130. David and Pete report that on
a hot day in the Western Cwm carrying a load their pulse
rates are around 160.Breaths per minute at Camp II while
lying on back in tent is about 22 per minute. It varies at
ABC from 22 at rest to 40 at mild work to 60-70 at hard
work. All our best and good luck with your own results.
Question:
Hello: I am a physician in San Diego. Are you all taking
medications to help with altitude, such as Diamox or
Decadron? What are your medical contingency plans if someone
starts to get altitude sickness? Do you have a physician
along with you? This is an interesting study. Are there any
control groups involved? The results that you get will be
much more valid if you are comparing results to a similar
group at sea level, as well as at various altitudes at the
same time. Unless variables such as medications and oxygen
use are taken into account, your results will be skewed and
possibly meaningless. (You have probably already thought of
all this, I'm sure). Good luck! I wish you all well on your
endevour.
Sincerely,
Robert Power, MD
San Diego, CA
Response from Base Camp:
Some of us have taken Diamox to enable us to sleep (and
breathe) at night. If someone becomes ill from altitude
sickness, we generally adhere to the rule of sending them
down to a lower altitude. In extreme cases we might put them
in a Gamow Bag to temporarily alleviate the symptoms and
then send them down. Diamox and Dexamethazone are always
options, too. We will have a physician (Howard Donner)
joining us in about 10 days. But, there are many doctors
here at Base Camp who are familiar with mountain medicine.
There is also a clinic at Pheriche at 14,000 feet which is
about a day's walk from here. There are already existing
control groups that have been studied at varying altitudes
in the past years. Our intention is to study 4 elite
climbers who have excelled beyond others at high altitude
and are willing to partake in specially designed tests on
Everest. We are a small sample, but we are very interested
in what the data on these 4 climbers will tell us about peak
performance at extreme altitudes.
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