Nancy Hansen (r.) and Ralf Dujmovits at the DLR

“We were the mice for five weeks,” says Nancy Hansen describing the time she and Ralf Dujmovits – as reported – spent in a hypoxia chamber at the German Aerospace Center (DLR) in Cologne half a year ago. The goal of the study was to find out whether, under certain circumstances, extreme hypoxia can lead to a strengthening of the heart in humans – as previously found out in two experiments with mice in the USA. After an acclimatization phase of around two weeks, the climbers had spent 16 days at a simulated altitude of 6,700 meters or higher, including four days at an oxygen content of only eight percent, which corresponds to 7,112 meters. “I suffered quite a lot,” admits Nancy. “But it was a big privilege to be part of the study.” Ralf is also still impressed by the experience: “I was hard on the edge. To be honest, I wouldn’t do it again. I underestimated the whole thing.” Last week the couple was in Cologne again – for one of several follow-up examinations. The first preliminary results of the study are now available.

Only 56 percent oxygen saturation

Pulmonary function test on the climbing wall

Extreme hypoxia initially had different effects on the bodies of Nancy and Ralf. Ralf, due to his many expeditions to eight-thousanders apparently better accustomed to the lack of oxygen, acclimatized much easier than Nancy. “One of the DLR doctors told me: ‘I hope you feel better than you look’,” she remembers and smiles. Once, the 50-year-old Canadian had an oxygen saturation of only 56 percent, a hospital patient would have been a case for intensive care. A DLR team was on duty around the clock for the two climbers. The scientists took blood and urine samples, carried out ultrasound and MRI examinations or cognitive tests. The analysis of the huge amount of data from the various tests is far from complete.

Both climbers lost muscle mass, they slept worse. It was astonishing that Nancy’s and Ralf’s responsiveness and concentration ability remained almost constant, even under extreme hypoxia. “However with the restriction that they were really challenged by the cognitive tests and had to concentrate,” says Dr. Ulrich Limper, who led the DLR study together with Prof. Jens Tank. During normal conversation, some “dropouts” were noticed.

Kidney performance also declined

Leaving the hypoxia chamber after five weeks

In Nancy’s heart, the right ventricle swelled and the pumping capacity decreased. In her brain, minor so called “White Matter Lesions” occured, which are frequently found in elderly people. In Ralf’s brain, the veins swelled over time without the 57-year-old suffering from severe headaches. In addition, the kidneys of both climbers worked much worse under hypoxia – albeit still sufficiently. “The good news is that all symptoms disappeared within 30 hours after Nancy and Ralf had left the hypoxia chamber and breathed normal air again,” says Dr. Fabian Hofmann, one of the DLR doctors.

It is not yet possible to say whether a damaged human heart is positively influenced by extreme hypoxia, as found out in the mice experiment. “We were dealing here with two healthy hearts of top athletes,” says Hofmann. “But it’s amazing what we can do to the hearth without structural change.” Further studies are to follow, if possible also with heart patients.

P.S.: Nancy and Ralf are about to set off for an expedition to Antarctica – to significantly lower altitudes than simulated at the DLR.

With Nancy Hansen (r.) and Ralf Dujmovits in the DLR hypoxia chamber

And suddenly the call came from space: “Here is Alex”. At first Ralf Dujmovits did not know who was talking at the other end of the telephone line: “Alex? Then I suddenly recognized the voice I had heard two days earlier during the broadcast of the rocket launch.” Alexander Gerst inquired from the International Space Station (ISS) about the condition of the German climber and his Canadian partner Nancy Hansen in the hypoxia chamber of the German Aerospace Center (DLR) in Cologne. “It sounded like he was sitting next door.” For a quarter of an hour, Ralf, the first and so far only German climber to have scaled all 14 eight-thousanders, spoke to “Astro Alex”, the first German astronaut to take command of the ISS. “He was very interested in our experience in the lab. That was great.” Of course, Nancy talked to Gerst too. For both climbers it was a “real highlight”, says the 49-year-old Canadian.

Underestimated strain

Alexander Gerst watching World Cup football at the ISS

After five weeks in the 110 square meter hypoxia chamber, the door will open for Dujmovits and Hansen on Tuesday. Then the experiment will be over, in which it should be tested whether heart functions improve during a long stay in extremely thin air. Ralf and Nancy spent the last two weeks all day at a simulated altitude of 6.718 meters and slept at night at 6,490 meters. That left its mark. “You see us quite tired here,” says Ralf, when I visit them (with bottled oxygen) again last weekend. “I had expected otherwise. I was convinced that we would be a little tired at first, but after a while we would get so accustomed to the low-oxygen conditions that we would be able to cope well with it. I underestimated how exhausting the whole thing is.”

“A huge success”

One reason for this fatigue may be that – as it turned out with Ralf’s MRI – the blood in the veins of the brain has become extremely congested over time and the veins are swollen now. “I’ve never seen it so massive. At first glance, you’re not happy about this,” says Dr. Ulrich Limper, who leads the DLR study together with Prof. Jens Tank. “On the other hand, it is not a direct threat. We assume it will regress.” In four weeks, Dujmovits and Hansen will return to DLR for their first follow-up examination.

The scientists have collected a great deal of data that will now be evaluated. First results are expected to be available within six months. “It’s already a huge success for us,” says Limper. “The concept worked, we learned a lot. We are still cautious, but clinically it looks as if our hypothesis that certain heart functions improve under the influence of hypoxia could be confirmed. If we can substantiate that with the data, it would be great.” The study might even lead to new therapies for heart attack patients.

“Swollen” heart

Nancy on the mobile climbing wall

Originally, it had been planned that, after an acclimatization phase, the two climbers would live day and night at a simulated altitude of 7,112 metres for two weeks. But the scientists had to change their arrangements. At that simulated height, Nancy’s pulmonary artery pressure – the pressure with which the oxygen-poor blood is pressed from the heart into the lungs – was significantly increased. The right half of her heart was therefore, to put it simply, “swollen”, Nancy’s values were at the limit. “From our point of view it would not have been successful to ‘chase’ her up”, says Limper. “Her condition probably would have gotten worse.” Therefore the simulated altitude was lowered to below 7,000 meters, at night even further down than during the day. “Nancy’s body coped with this. Her values slowly improved and towards the end approached those of Ralf again.”

Not much higher than 7,000 meters

Does the body learn from frequent stays at high altitude?

According to Limper, it is assumed that in Nancy’s case it was a “normal reaction of a heart that is simply not yet accustomed to very high altitudes”. Ralf also told about health problems during his first expeditions, which no longer occured during his later projects. “There may be something like a long-term adaptation,” says the physician, adding that this has not yet been scientifically proven.

Nancy’s troubles made her and Ralf think. “It shouldn’t be a problem to tackle a seven-thousander where we spend the last night at 6,300 or 6,500 meters,” says Ralf. “But above that altitude, Nancy could suffer some damage to health. That’s what we’ve learned, and we’ll take that into account, of course.”

Constantly felt cold

Less muscular mass

During the time in the hypoxia chamber, both climbers have lost more than two kilograms of body weight each, primarily muscle mass. “The upper arms have become thinner,” says Ralfs, “and where normally the trousers are taut on the thighs, now everything flaps.” The climbers’ weight loss was lower than expected, says Ulrich Limper. “We attribute it to the fact that apart from hypoxia they had no stress factors as usual in the mountains: no cold, no pitching up the tent, no continuous physical strain. In the end, they moved very little.” Nancy and Ralf tried to stay reasonably fit on a treadmill, an ergometer and a mobile climbing wall. One of the surprising findings for the scientists was that Ralf was exhausted after 50 minutes on the ergometer, but did not sweat at all. It also seemed unusual that despite a room temperature of 24 degrees Celsius Nancy and Ralf felt so cold that they pulled two jackets over their T-shirts. So there are still a few question marks.

Into the sun!

“It was worth the effort”

Nancy and Ralf do not regret getting involved in the DLR experiment. On the contrary. “I would do it again,” says Nancy. “Scientifically I found the whole thing incredibly interesting. Of course, not every moment was fun, but overall it was an amazing experience that was pretty unique.” Also for Ralf “it was absolutely worth the effort”: “We leave the project healthy. And if we can make a contribution to the future development of a therapy for heart attack patients, then everything is perfect.”

And what are they looking forward to the most? “Sunshine,” Nancy answers quick like a shot. Ralf especially longs to see his family and friends again and is looking forward to sitting in the garden, running through the woods or cycling on his mountain bike for hours: “We had an incredibly committed team of scientists and doctors around us. We enjoyed it, it was exciting, and we learned a lot. But now it’s good that we’re coming home.”

Ralf Dujmovits and Nancy Hansen

The doors have closed behind Ralf Dujmovits and Nancy Hansen. The so far only German climber who has scaled all 14 eight-thousanders and his Canadian partner moved in a 110-square-meter hypoxia chamber of the German Aerospace Center (DLR) in Cologne on Tuesday. As reported, the two mountaineers are participating in a study conducted by DLR in cooperation with the University of Texas to investigate whether extreme hypoxia can also have a positive side effect for human beings. US researchers from Texas found in two experiments with mice that heart muscle cells devided when the animals were exposed for two weeks to oxygen deficiency corresponding to conditions at 7,000 m. In mice which had previously been triggered myocardial infarctions, cardiac function improved after two weeks of hypoxia.

Medical control around the clock

Monitor in the control room

Ralf and Nancy, both healthy, are the subjects of the pilot study. They are to stay in the hypoxia chamber for about a month. In the first few weeks, acclimatization as on a Himalayan expedition is simulated. The oxygen percentage in the air will be gradually lowered and temporarily increased only twice in between – as if the two climbers would descend again to breathe thicker air. The last two weeks, the 56-year-old German and the 49-year-old Canadian are to  spend in a simulated height of 7,000 meters. The experiment can be stopped at any time in case serious problems arise. A DLR research team monitors Dujmovits’ and Hansen’s state of health around the clock. The daily schedule includes heart and lung function checks, blood and urine tests, fitness checks and so-called “cognition tests”, which check the reaction and perception of the subjects.

Yesterday, I visited the two climbers in their new “home”. That was possible on Wednesday for the last time without breathing mask. After more than half hour in a simulated altitude of about 3,700 meters, I felt a little bit dizzy. I preferred to do the interview with Ralf subsequently in thick air, by phone.

Ralf, you can not get out, there is no daylight, and the oxygen is lowered. That does not sound like a holiday apartment.

Nancy has a pulmonary function test

No, it isn’t a holiday apartment. But we have adjusted ourselves to it over a long period of time. We took it that way. We prepared ourselves mentally for almost nine months. Now we are here and actually feel quite well.

How does the prospect feel of being locked up for weeks and not being able to move to fresh air? That must be almost like torture for a climber.

Not even like that. I have the great privilege that I was allowed to be outside a lot. I do not see a big problem with being inside for five weeks now. We have been asked this frequently. But neither Nancy nor I are very worried that we can not handle it. We both can be very focused on special things. We have agreed to it and accept it as it is.

How did you prepare for this experiment? Have you filled up as much fresh air and nature as possible?

Skiing down to Monte Rosa Hut

We were in Valais for a week. We spent the final two nights on the Gnifetti Hut at 3,700 meters, followed by a night in the winter room of the Capanna Margherita on the Signalkuppe at 4,550 meters. So to say, we had pure nature for us. We were completely alone on the Capanna Margherita for 24 hours. We got up at 6.30 a.m. to enjoy the beautiful sunrise. Then we skied down to the Monte Rosa Hut through best powder snow. We really filled up, had a great time and, of course, a bit of pre-acclimatization too.

What motivates you to participate in this study?

Nancy had in her family environment some cases of heart attacks that ended either deadly or in very difficult recovery. Therefore, motivation for her is really to be able to bring something forward in the field of research. It’s similar with me. My interest in medicine has always been there and will continue. Being able to be possibly part of a new treatment for heart attack patients is a great story.

Maybe it’s also an additional motivation that this “seven-thousander”, which you want to scale, is still unclimbed.

Of course, it’s a bit of a first ascent. (laughs) But it’s not so much this first-time act that motivates us, but rather the support to get a step further in heart attack research.

Nitrogen tank in the DLR outdoor area

Are you also worried, be it mental or physical, when you consider the weeks in the hypoxia chamber?

There was a big unknown we both had a hard time with. It is not so easy to convert the percentage of oxygen in the air to (virtual) altitude. We have to rely on what Jens and Uli (Prof. Jens Tank and Dr. Ulrich Limper from DLR, the heads of the study) had predicted. But here we also have the opportunity to see how the air is composed by means of sensors installed in all rooms. From my feeling, that fits very well. Therefore, the trust that we must have in the team, is absolutely justified. We feel we are really in good hands here.

You are now the first complete day in the hypoxia chamber, at a quasi-altitude of about 3,700 meters. Does it feel different than on a mountain?

Of course, it’s different because the hardness factors such as strong sunlight, wind, cold, storm or snow fall are missing. So, of course, it’s much easier. But the thin air feels as we know it from high altitude – although the height is simulated by reducing the oxygen content. Normally, this percentage is always the same, no matter how high you are. (The hypoxia is caused by the lower pressure with which the oxygen is pressed into the lungs.) Here nitrogen is pumped into the rooms and thus the oxygen percentage decreases.

Do you think that you will learn something about yourself in the next few weeks?

Mobile climbing wall in the living area

I have already learned a lot. There are many, many little things. For example, we trained on the mobile climbing wall yesterday. It was specially set up for us here because we wanted to stay fit while climbing. We immediately noticed that not the lack of power in the arms or fingers will be the limiting factor, but the stamina in the thin air. We underestimated that. If we climb the overhanging part of the wall here, we’ll probably never get to the point where we run out of energy, but we’ll be at the limit in terms of endurance.

Does it help you to get through the whole thing as a couple?

That definitely makes it a lot easier. Yesterday at dinner I briefly imagined what it would be like if I were sitting here alone, maybe watching the news and then going to bed by myself. That would be terrible. You do not have anyone to talk to about what happened during the day. Being able to do this together with your partner is really great. We have a lot to laugh about. But we had also the first difficult moments during the night. Nancy suffered from headache, I had a slight pressure in my head. You talk about it, and then it’s a bit easier again.

Is it a bit like sitting in a base camp in bad weather and not being able to avoid each other?

You can really compare it. I remember for example 2009, when we were stuck in Lhotse Base Camp for three weeks in extremely bad weather and could only switch between our personal tent and the mess tent. It’s not much different here. However, we actually have more space to move, because the rooms here are very spacious. In addition, we have a lot of tasks to do during the day.

Ralf has a ECG

What do you expect, how will you come out of this experiment? As a physical wreck?

That’s the big unknown. We originally planned to go on expedition afterwards and use this extremely good acclimatization. However, cause we have no idea whether we are still fit enough to climb an interesting mountain, we have limited our plans to the Alps. There are e.g. on the south side of Mont Blanc so many high-altitude destinations. If we’re still fit enough, we’d rather go there instead of buying a permit, having to pay a liaison officer in advance, and then maybe having to say: We’re too weak, it’s just not possible.

But it’s also possible that you will be just lazily lying in the sun?

It’s possible too. After the time here in the chamber, the trade fair “Outdoor” will take place in Friedrichshafen. After that we’ll have a bit of time left without obligations. Maybe then we will be lying in the sun.