tonight everest in 1996 8 dug in a single day now nova takes you back to explore the effects of altitude on the body and mind and a new drama unfolds will the summit claim the new victim what's going on yet breathing quickly right now won't help you Carter and I know this is really scary Everest the Death Zone [Music] major funding for Nova is provided by the park foundation dedicated to education and quality television this program is funded in part by Northwestern Mutual Life which has been protecting families and businesses for generations have you heard from the quiet company Northwestern Mutual Life and by the Corporation for Public Broadcasting and viewers like you [Music] five and a half miles above sea level the high Himalayas stand fixed against the wind and clouds the air is so thin it is not life sustaining within hours the living begin to deteriorate but humans come here and struggle for each breath to stand briefly on the highest point on earth it's a living hell the only way to describe it is an utter exhaustion you really don't care if you die or if you just sit down and don't go any further in 1996 eight people died in a single day on Everest scientists believe many if not all of those deaths could have been due to hypoxia or lack of oxygen to the brain judgment becomes impaired person becomes confused they don't even know where they are as it gets worse people hallucinate so all sorts of mental changes can take place as the brain starts to become more and more abnormal it's a very slow and arduous process you take a step you breathe you take another step that's all your mind is occupied with is taking each individual step for every six successful summits on Everest one person will die with more people climbing into the Death Zone above 26,000 feet one critical question is how oxygen deprivation affects the brain David Breashears a high-altitude climber and filmmaker has stood on top of Everest three times this hard work everything about being at altitude is hard we go up with the best technology available to us the best training and you can still end up frozen to death at twenty-seven thousand five hundred feet that's what makes Everest Everest David was making the IMAX film Everest last year when a storm claimed eight climbers lives he helped rescue some but others were beyond help he is returning to film and lead an expedition that will explore the effects of altitude on the body in mind everyone thinks that they're thinking very clearly up high and yet by virtue of going up into that atmosphere you greatly increase your likelihood for making an error on the early Everest expeditions climbers trekked for weeks to get to the base of the mountain today they fly into a Sherpa village at 9,000 feet [Music] it will take 10 days to ascend the 9,000 feet in elevation to Everest base camp [Music] base camp is a temporary city of tents housing 300 people to support nine expeditions the accommodations may be crude but most teams have a satellite link to the outside world it looks like there's about 30 people standing there David Breashears meets up with his team members and they scope out the route up the mountain uh-huh what do you guys think about the upper part there before camp one David Carter from Indiana is returning to Everest after an unsuccessful attempt in 1991 we always put ladders there and that's the toughest part of the whole ice bother Vee stirs will be guiding Carter considered one of today's premier high-altitude Mountaineers it has climbed Everest four times twice without oxygen Zankou Sherpa climbed Everest for the second time on David's last expedition he is in charge of the large Sherpa staff that will support the team these climbers will take part in a battery of scientific tests that will gauge their performances at altitude heed Easter's lives and trains in Seattle two weeks before leaving for the mountain the climbers joined him at the University of Washington for baseline tests dr. brownie Shanee looks for physiological clues that determine who will perform well at altitude one determinant is lung capacity is it important to have big lungs yes it is because in that regard you can move more air obtain more oxygen within the lungs that then the blood can pick up and deliver to the vessel tissues when we breathe in oxygen molecules pass through the lungs into the air sacs here purple oxygen deficient blood cells become revitalized and red with oxygen and are pumped by the heart throughout the body dr. Shanee measures the climbers heart rates and ability to work Carter is well above average at the elite level our ed Viesturs and David Breashears elite biology climber can judge through the snow break trail climb up a cliff at their maximum capability for hours high on Everest many climbers approach their maximum heart rate just gasping in the thin air some may collapse unable to go on the amount of oxygen in Carter's blood is measured by dr. Howard Donner Carter this little machine that goes beep next-gen is an oximeter the top number here is your saturation which is a measurement of the amount of oxygen in your blood 100% means that you're completely saturated which is what we'd expect close to sea level as you go higher this number is going to drop this lower number is your pulse you see you have a nice slow pulse at 63 which is normal for you recipe and as you go up in altitude a normal response is to see your pulse rate go up Carter is now given a decreased level of oxygen to simulate going to high altitude his body strives to get more oxygen as Carter's blood oxygen saturation Falls his breathing increases and his heart speeds up trying to pump more blood made red with oxygen to his organs over time more oxygen carrying blood cells will be produced to carry the oxygen where it is most needed to the muscles and brain these physiological changes are called acclimatization and they enable a person to survive at high altitude due to this sudden exposure to high-altitude Carter's oxygen saturation plummets he will ultimately pass out from the lack of oxygen to his brain we've found some abnormalities previously in high-altitude climbers dr. Peter Hackett addresses the climbers on the effects of decreased oxygen to the brain one of the more pressing questions in high-altitude medicine is does climbing to extreme altitude cause brain damage and we're gonna be looking at a number of ways one is by MRI scans some work indicates that some climbers who go to extreme altitude without oxygen do come back with slightly smaller brains if cells of the brain actually die the brain will get smaller that's what happens with strokes and other things that cause brain cells to die so we'll look at the volumes of the brain by these special scans these are unusual people and they're going to a very unusual place so there's some opportunities here David and Edie have been to hell titude many times and we might expect them to react a little bit differently than David Carter who is a relative newcomer at these kind of extreme altitudes I've lived by the river for 20 years and only twice before psychometric testing will reveal subtle changes in the climbers abilities to process information as they go higher one what we will expect to see is that there is a slowing in speech there'll be a slowing in reaction time we may see a lot of misspeaks they won't say things quite the way they would at sea level they'll be slurring and hesitations this one's a little more difficult this time what you're going to do is go down the columns and you're going to say the color that you see you have disregard the word you see tell me the color that the word is printed in tray blue red green blue red blue green red green blue green if Charles beats David in a sprint which man is the faster runner Charles people like ed Viesturs and others who make a career out of doing these very high peace without oxygen may have some long term brain abnormalities some studies indicate that they do have very minor subtle cognitive dysfunction and we found only on psychometric testing there's nothing obvious and their MRI showed that there can be structural changes we have yet to have a good correlation between the MRI structural changes and the cognitive changes that's going to take more time more studies more research like we do me now dr. Howard Donner treks into base camp where he will be stationed to monitor the health of the climbers this is dongbu you know you look blue here give me your hand I got a pulse oximeter here you're alive okay your saturation level of 74 your pulse is about 85 a blood oxygen level of 74% would be alarming at sea level but is normal for someone who has just reached 18,000 feet warmed up as Howard acclimatize is over the next few days the level of oxygen in his blood should increase if it doesn't he may become ill with acute mountain sickness the early warning signs of mountain sickness are primarily headache followed by dizziness trouble sleeping and lack of appetite and then as it progresses one develops a more severe headache nausea and vomiting and trouble with the balance or coordination and that is the hallmark sign of progression two definite cognitive problems I'll head out a to sickness before and I know how bad here they can get the two things that really affect you are shortage of breath and the lack of sleep sometimes you arrest and you feel okay then you start walking in it's not okay I put my head is going to bigger like this uh-huh and I experience the most shocking headache I've ever had in my life and I felt sick and nighttime I took two aspirin after that so never I felt myself to get her act now I'm fine if symptoms get worse a portable hyperbaric chamber known as a gam off bag can help what's your altimeter say before you get in C we're about seventeen thousand six hundred feet all right the bag is inflated to increase the pressure inside this results in a higher density of oxygen molecules this simulates a descent of several thousand feet where the ambient air holds more oxygen Doug what's your altitude I'm in about fifteen thousand three hundred feet now if this altitude pumping this bag up to two psi will bring a patient down to an altitude inside the bag of about eight thousand feet lower than we are here Doug what else do you add most of the time putting a patient in for a number of hours they're gonna get some benefit let's pretend Doug couldn't walk because of severe forms of mountain sickness we put him in for four or five hours and now he's able to walk down the hill under his own power so that's a big help okay Doug I'm gonna stop pumping and slowly deflate within seconds the pressure decreases and the patient returns to 17600 feet are your ears okay Doug good so he's back to base camp you can tell by the fact that there's no more tension thank you very much it's 5:30 in the morning here at base camp we'll be doing a little filming today with Zhong that's why I'm here we're going to harness on and our crampons and those are all our tools for the ice ball and so I have to eat and drink and get ready to go the Khumbu Icefall is a steep glacier riddled with deep crevasses and huge ice blocks it can only be traversed with the use of ladders and rope fixed and maintained by a team of Sherpas [Music] it is here at the beginning of the climb where the greatest objective dangers on Everest lie [Music] [Music] on this section for ladders are strapped together to help climbers scale a hundred foot wall of ice [Music] sangmoo and david use mechanical ascenders to climb up the fixed ropes this is called humoring the Icefall is a jigsaw puzzle of giant blue-ice puzzle pieces the size of houses weighing some 30 tons each without warning the blocks can shift and crevices cave in taking climbers with them [Applause] David Joo Mars at the last page of the Icefall to arrive at camp one okay everybody down there this is David from camp one ready to proceed with the high altitude tests and I wanted to start out with giving you my current pulse oximeter reading I do you copy and how are you down there hi Jenny we really miss you up here I'm gonna stick this thing on my finger so stand by my heart is racing because I have to take this damn test up here and I'm nervous as how hopes it just went up so Jenny I have it on my finger the oximeter reading is eighty a more realistic reading from my pulse was a few minutes ago it was 78 but now that I have to take this test and I get all this test anxiety my pulse is racing at 104 green red blue red green red along with edy stirs David Carter has also reached cap one Carter this is true and false I just want you to read the number of each question and tell me whether it's true or false yes 60 seconds 51 is false 52 is false 53 is false 54 false 55 false 56 true 57 false 58 falls through 58 is true 59 truth oh hi yet hi good sleep yeah guess we're going Hawks ijen warmth cotton clothing all shower oh hell just stay up there at the top of the Icefall there is a bottleneck of climbers edy stirs puts on his pack at the back of the line it's only one at a time on the ropes edy David and Carter all descend back down to base camp from cat one this will be the first of many trips through the Icefall in their long schedule of acclimatization it takes time for the body to adapt to higher and higher altitudes climbers will typically ascend to camp 1 twice from base camp they move up to camp 2 and sleep there several nights before moving to camp 3 before their final push to the summit climbers descend to base camp to rest and gain their strength before trying for the summit while climbing down through the Icefall the climbers cross paths with a line of Sherpas bearing loads for the higher camps Sherpa is the name for the indigenous people who live in the Everest region although they adapt well to altitude they're not immune to its debilitating effects if they push themselves to go up too quickly they too can suffer from acute mountain sickness at base camp the climbers hear the disturbing news of a Sherpa who was found near death lying in the middle of the trail when I saw him his eyes his pupils were fixed and dilated his barely had a pulse and he died several minutes after I got there I think he had high-altitude pulmonary edema with pulmonary edema the blood vessels in the lungs start to leak they leak this plasma fluid that is tinged with red blood cells so it's a little pinkish and the air sacs start to fill up with in different parts of the lung usually the right first and the left and eventually they all fill up with fluid the person starts coughing this pink frothy sputum can't get any air at all their blood oxygen level drops and they go in a cardiovascular collapse and die with each breath he was blowing bubbles through the fluid in his nostrils and and and mouth he was drowning in in he was drowning in his own secretions from high-altitude pulmonary edema the treatment is descent if the patient can't walk then oxygen or a gam off bag must be used can I check your situation again Malaysian expedition doctor measures a sick Serpas blood oxygen saturation but on oxygen he's now got a situation of about 91 percent which is considerably different than what it was yesterday this morning at breakfast we noticed a team carrying this sick shirt but this is logged by our camp and we're now at the helicopter landing zone with dr. Sneha ku say Hawk what went on with luck well he was very ill indeed when we when we came across him he was a bit confused he was quite ashen gray he was quite breathless as well and we checked his saturations and to my alarm it was 20% we slapped some oxygen on him and it came up to about 70 80 % with 3 or 4 liters a minute and because he was able to tolerate lying flat we decided to put him in the gamma bag which we did for two hours and how did he respond to the gammas he did very well he was comfortable in it but the fact that he had symptoms on both sides of his lung and the fact that he was so unwell and so desperately short of oxygen we treated him for Pommery edema when a helicopter arrives at base camp it means a person is in need of immediate evacuation and for Lhakpa a quick descent to Katmandu will save his life pilots don't hesitate long hair and they breathe supplemental oxygen you've suddenly exposed to the altitude of base camp the pilot could become desperately ill from acute mountain sickness in the early morning freeze the climbers silently put on their crampons to climb up through the ice ball for the last time [Music] the team has been on Everest for several weeks acclimatizing at the higher camps time is running out for an attempt on the summit Carter has developed a high-altitude cough which he knows could jeopardize his chances of completing the climb it's a real violent cost it comes from deep within and you can't control it my main concern right now is when I get higher the COFF will get worse and I'm worried about breaking a rib or vomiting or something a chilling reminder of how dangerous Everest can be human remains resurfaced from the depths of the moving ice floe obviously remains of a climber spread out around this area this is a an inner boot made out of a synthetic material making it probably a vintage and there's still portions of the bony structure of the foot inside right here maybe the most obviously human portion of the skeleton is the head of the femur and over here a tibia and a fibula still intact still together and this kind of stuff is spilling out all the time and a reminder of some of the drama that goes on up in the Icefall the climbers bypass camp 1 and enter the Western [ __ ] on their way to camp 2 this high glacial valley is transected by massive lateral crevasses [Music] [Music] I'll pretty good a long day it's about 12:30 I started at 5 a.m. base camp don't you have something really fun to do today no nothing fine just relax it I thought you're gonna do some testing in here oh yeah we got to do some testing a that's right okay Oh mental testing reading some lists and memorizing and stuff like that I think you're gonna do I have no idea we'll soon find out the action of the brave cyclist kept a small boy from bringing hit by a 10/10 for today I'm suffering badly we're up at six and a half thousand meters and often it feels fairly poorly here anyway I think I was suffering from AMS acute mountain sickness was vomiting and diarrhea means that I couldn't drink or eat anything so I'm feeling but weak this is the part of high-altitude mountaineering that wasn't nice being being sick it's hard enough as it is but when you're sick as well and all your reserves are gone and it's very hard to catch out if guy Kotter symptoms get worse he'll have to descend there is a delicate balance between acclimatization and physical decline climbers know that they can only stay at altitude for so long you know I'm nervous I don't know how I'm gonna perform I'm also nervous that we're sitting down here and and my body is slowly deteriorating the longer we stay at this altitude and I and I slowly get weaker and weaker humans will start to deteriorate because of the high altitude at around 17,000 feet sleepy becomes a problem muscle wasting takes place weight loss takes place this process of deterioration takes place much more quickly the higher altitude that one goes to so over 26,000 feet is called the Death Zone because acclimatization is essentially impossible what you camp 3 tomorrow we're to go up early around we're gonna get out of here probably about 6 o'clock I'm on an antibiotic now I ended up getting a pretty good head cold about three days ago and yesterday I was really feeling pretty bad when I came into camp - I was dehydrated and basically just weak from the cold but the antibiotics been kicking in and I'm feeling pretty good today and looking forward to going tomorrow in the morning they march to the top of the western comb where they begin the arduous ascent of the load see face [Music] Carter to face you copy hey Doc its Dave for at basically the bottom of the load see face where L evasion is at twenty two thousand three hundred and how you feeling right now symmetry data if you have it over pulse is around 140 when I rolled in and blood oxygen saturation with sixty percent is low but Howard is hopeful that Carter saturations will improve over time David Breashears interviews Carter an hour below Camp three the feel huh sorry I feel I felt better before I climb out altitude yes it's it's slow you're winded dehydrated losing your voice coughing but the views make it worth it camp 3 sits halfway up the load see face a 45-degree wall of glacial blue ice okay that's huff and puff it up here the pace is slow as ed and Carter ascend into thin air the route is fixed with ropes and they fall into the rhythmic movement of kicking steps pulling and stepping up yeah good job it's good to be here we gotta get some careful walking around here that's kind of steep especially without crampons on yeah many climbers have died here slipping off the face from one Pony play step don't you think this is a little absurd I'm sitting on this little ledge out here in front of my tent at the 24,000 feet I'm ready [Music] of the first avenue bank the video camera captured the daring bank robbers robbery of the First National Bank the action of the brave cyclist help save the boy let's see I know I have to say all I know prevent the boy being hit by the 10-ton truck his hard work everything about being at altitude is hard I can't show you that there's no oxygen molecules in the air here there's only 35 percent of the oxygen you're breathing down there at sea level available to me right now we have to finish this expedition the ice falls going to close our permits up we've been here a long time but we're also extremely cautious and we're not going to push it one bit we'll do our research as high as we can and go home knowing we've done the best we can you know the austin really helped yeah real good now a lot better Howard it was a lot worse when I was you know I'd wake up after two hours and I felt like I had a lot of [ __ ] him I wrote and I'd caught it up it's kind of a hard chunk snot type [ __ ] it was yellow over yeah after a few hot drinks and getting off OHS and breathing through my nose I feel a lot better alrighty I I don't know I'm kidding we're at Camp three we're getting ready to move out Carter is about to go higher than he has ever been before looking up the route some 50 climbers clamour towards the highest camp on the mountain this makes David Breashears and ed Viesturs very nervous they witnessed last year that crowded ropes on Everest can be deadly this year it seems nothing has changed as climbers wait their turn on the ropes they increase their chances of becoming hypoxic tonight they will all leave camp and climb toward the summit David and edy climb into the Deaf zone and altitude where humans are only transient visitors the tents of camp four finally come into view it is taken nearly two months for the climbers to reach this point and what will transpire over the next 24 hours will change their lives [Music] oxygen bottles from expeditions years ago litter this wind scoured place temples when you die at 26,000 feet no one has the energy to carry your corpse off the mountain the climbers are slowly deteriorating their bodies literally consuming themselves for energy simple tasks take longer to perform and precious energies burn just gasping for air while most climbers are resting David Eadie and Carter endure another round of psychometric tests old houses are more difficult to maintain but worth the extra time and old houses are more difficult to maintain but our worth the extra effort and only twice before and all those years has it been this high we have to buy the river for 20 years and this was the first time it had been this high over the wildflowers broom dim profusion in the high meadows in August day vyd radios Edie who is in a nearby the scene feels all too familiar going up today with all these people if they do of course I don't like to be around people staggering around like that and I don't know I'd like to see this day just kind of sort itself out without me in it it's a brief moment of doubt but in the end David decides to go up knowing he can always turn around five hours later the climbers prepare for their departure at this altitude loading a pack and putting on crampons will take two hours each climber carries two bottles of oxygen they leave at 10:00 p.m. when one considers the condition that a climber is in on the South Col on summit day it's really amazing that they can reach the summit at all first of all there hasn't been sleep for usually a couple nights there hasn't been enough to eat or drink even if they've been on oxygen it's still been very uncomfortable to breathe the mucous membranes are all dried out there's always a sore throat there's always a cough there's often a headache and it takes a tremendous amount of will to keep going under these conditions at 5:30 in the morning and 300 feet below the summit David calls down to Howard [Music] they sit down to rest ten feet in front of them lies the body of Rob Hall one of the expedition leaders who died in 1996 David points to where Rob is buried under wind-driven snow recent pace [Music] they have only 300 vertical feet to go but two hours of climbing they traverse a knife-edge Ridge which crops off 8,000 feet on both sides david climbs in front they reached the Hillary step a 40-foot wall of exposed rock this is the most technical terrain on the summit day climbers maneuver up the cracks and over the rocky outcrop while clipped into the fixed ropes Carter hoists himself up only one climber can ascend at a time this is where bottlenecks occur they silently pass by the body of a climber from an earlier expedition who died here on the roads the breathing becomes unbelievably difficult you feel like you're one huge lung the heart rate at rest becomes higher and higher the maximum heart rate becomes lower and lower and as you go higher those two get closer and closer together and of course when your resting heart rate equals your maximum heart rate while you can do is rest you can't do any more physical work they've climbed for nine hours sangmoo raises the Tibetan flag on the summit David is sitting on the top it is taking the last steps up with Carter just behind David we read you loud and clear where are you over [Music] [Music] David Breashears has reached the summit of Mount Everest for the fourth time ed Viesturs has now become the first non Sherpa to climb Everest five times in return Rob Hall's fifth summit last year was tragically his last Carter has lost his voice and will be unable to take the world's highest psychometric tests Mike walked around the block three times at 78 David's blood oxygen saturation is good for a climber breathing supplemental oxygen climbers consumed bottled oxygen and a flow of two liters per minute on the summit day with his mask off for a few minutes David's respiratory rate increases significantly fortunately we did pass one body right on the pigs rope it only makes me question my sanity [Music] edie takes his final psychometric test on Everest let us know how you're doing how you feeling over the descent is quite arduous you're physically spent you have to think about what you're doing you can't just stagger and slug your way down a lot of accidents and mountaineering occur on the descent and it's because people get to the summit and they're totally let down their guard and they've used all of their energy just to get to the top it takes five hours to climb down to camp four in the safety of his tent David reveals to Howard that he had a difficult climb to the summit Howard is cold hey David this is Howard go ahead [Music] [Music] David Carter's condition is worsened despite his own illness David Breashears picks up the camera to shoot Edie taking care of Carter tell me what's up he's at 93 and 133 so your pulse ox is really good okay he's on a four liter flow David started having problems coming down in the South Summit couldn't catch his breath so we called the doc at base camp told him what was going on and he doesn't doesn't know whether it's something like pulmonary edema or possibly the fact that David was having some lung infection earlier on that he's been fighting and whether the altitude just exacerbated death so I think the best option if he can handle it is to get him down to camp to the lower we get him the better yeah there's a bottle they have just climbed to 29,028 feet the summit of Everest and exhausting accomplishment now they will try to descend five thousand more feet to get Carter to a safer altitude David Brashear stays at Camp 4 to rest as edie accompanies Carter he would go 10 or 20 feet and then we'd stop for five minutes you know he'd have to catch his breath he'd have to take his mask off he was overheating desperately trying to get control of his breathing I thought we could get the camp to but as it turned out it took us a long time it took four and a half hours to get down to Camp three so it was about 7:00 p.m. then and we got into the tent and that's when it started to get a little hairy after hours of labored breathing Carter gains enough strength to get on the radio kardama man how are you doing tell me this is very important Carter I need to get a feeling for whether you feel like your lungs are full of fluid you feel like it's difficult to get air you feel really short of breath or do you feel more like it's wheezy in your upper airway like you have asthma over Carter seems to be improving but two hours later a desperate call from Ed and I'm gonna keep talking you don't have to respond see if you can do a Heimlich and get him to expel whatever is obstructing over okay II D listen to me I'm not sure where you're at if it's an obvious obstruction you can push it out with a Heimlich do that if it just seems like Carter's airway is closing and you need to breathe for him go ahead and start mouth-to-mouth ventilation / tell me what Carter's doing now what is his respiratory status over okay what's very important Carter for you is I want you to take nice easy slow deep breaths breathing quickly right now won't help you Carter and I know this is really scary you're gonna do fine but I need you to breathe deep in and out and in and out slowly and know that edie and the rest of us are gonna take care of you over david was desperately gasping for air I wasn't sure he's gonna make it through the night I mean he had his doubts and that's a scary situation to be up there all alone and thinking that you know here this guy might die on you that light came on that's plugged in okay David going on really long couple days for me I've been very sick coming down I'm totally exhausted having problems getting a full breath my throat feels like I'm breathing through a straw right now she's God's gift up here though the first time in my life when I literally thought I was gonna die I still to this point have not even thought of summoning I just want to get down the mountain choking to death at 23,000 feet the first thing that went through my mind was how isolated I am and I'm not gonna be rushed to hospital and revived I knew that when I was choking there's just two people there was myself and Ed and it was frightening I don't want to die I don't want to die in the mountains I don't want to die young but since I've survived it it's a big part of my life now ten days after coming off Everest the climbers returned to Seattle for a final session of testing the scientists have now had a chance to analyze the data the pulse oximetry data collected on this expedition showed as expected the decline in oxygen with higher ascent to altitude and David Carter in particular had lower blood oxygen levels which seemed to go along with some of the problems he was having on the mountain we need to do more careful analysis of the relationship of the pulse oximeter readings to the MRI scans dr. Hackett has looked closely at the MRI scans searching for abnormalities he discovers that exposure to extreme altitude can leave its mark on the human brain Hackett addresses the climate actually the only abnormality we found was a very mild atrophy in the brain of advisors who was the one that has climbed many times to high altitude without supplemental oxygen and what we'd like to do is follow him over longer period of time to see if this is something that might actually progress with his high-altitude career you were feeling bad there and we have reviewed all the tests you see and you can see that there's a real difference in your performance at high altitude at the higher elevations you're obviously in survival mode from the numbers we could see that your performance was deteriorating and had we had those numbers available we would have probably suggested that you might not want to continue I'm shocked and I realized now how sick I was and I just you don't it's just a haze up there you can't tell them no we're all just getting by yeah I'm looking at David for the first time at camphor and typically you know I'm talking to him on the radio and in fact you saw when he was coffee he had the microphone off so I'm hearing his responses I'm not watching him cough or seeing how awful he looks the question then we ask is what happens if you're in an emergency situation are you able to think quickly are you able to think clearly about what you need to do to survive and get down you can see how in his condition he could have not tied his rope correctly not tied into his harness correctly not clipped in the anchor correctly I love this mountain I have learned a lot I you know I summited but I still don't even think about this summit I'm still thinking about that night I can't three big near-death must be dying when I passed by the last ladder in the ice fall I knew that I had survived Mount Everest [Music] David we're curious now that you've been to the top you think this was your last strip up this mountain over [Music] ever going to the top of Everest again I need lots of people who've been beefing changing my mind [Music] [Music] take the tests yourself see the 360 views from the top return to Everest and experience everything with the extreme altitude start climbing @ww pbs.org educators can order this show for 1995 plus shipping and handling by calling 1-800 two five five nine four two four and to learn more about how science can solve the mysteries of our world ask about our many other Nova videos [Music] Nova is a production of WGBH Boston [Music] major funding for Nova is provided by the park foundation dedicated to education and quality television this program is funded in part by Northwestern Mutual Life which has been protecting families and businesses for generations have you heard from the quiet company Northwestern Mutual Life and by the Corporation for Public Broadcasting and viewers like you [Music] this is PBS