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.”

Visiting Ralf Dujmovits (r.) with mask

Bottled oxygen on a mountain has always been out of the question for me. On principle. Today I made an exception – for a “virtual mountain”. To be able to visit Ralf Dujmovits, the only German mountaineer who has scaled all 14 eight-thousanders, and his partner, the Canadian climber Nancy Hansen, it is mandatory to use a breathing mask. After two weeks in the hypoxia chamber of the German Aerospace Center (DLR) in Cologne, the two test persons have reached the simulated target altitude of 7,112 meters. The percentage of oxygen in the air, normally 21 percent, was gradually reduced to eight percent by adding nitrogen. “It’s like climbing a mountain. The acclimatization is almost done, now we’re heading for the summit,” says Ralf. “The time on the summit will be of course much longer.”

Short rest, then things gets serious

Nancy Hansen’s blood pressure is checked

In the coming days, Ralf and Nancy can once again briefly “descend” to breathe thicker air. On 4 June, however, the crucial phase of the study will begin, during which the two climbers are to stay constantly at a simulated altitude of 7,112 metres for two weeks. The aim is to test whether extreme hypoxia can strengthen the heart and even lead to the formation of new cells. If this finding from experiments with mice can be confirmed in humans, completely new therapeutic approaches would be conceivable for heart attack patients.

How much physical deterioration will there be?

Eight percent oxygen content

“We are both excited,” reveals Nancy. “I think the first few days will be okay. And then either it will feel normal or we start to deteriorate. Nobody really knows.“ Ralf recalls the French climber Nicolas Jaeger, who in 1979 in a self experiment spent two months alone in the summit area of the 6,768-metre-high Huascaran in Peru: “Cognitively he felt not so bad. In the end, physical deterioration became the major problem for him. I expect the same from us. We’re probably going to lose a lot of muscle.”

Breathe properly

So far, Hansen and Dujmovits have coped well with the low-oxygen time in the DLR’s hypoxia chamber. In any case, you can’t see yet what a burden they’re under. “I had three, four pretty bad headaches, mostly in the night,” says Nancy. “But it has gotten better.”  The 49-year-old Canadian finds it fascinating to see “what’s happening inside of our bodies, also in comparison between Ralf and I”. Her partner acclimatizes much better than her, says Nancy: “The way his lungs exchange oxygen with his heart is very different to my exchange. Ralf is teaching me how to breathe properly in here.”

Currently no climbing wall training

Pulmonary function test on the climbing wall

Dujmovits estimates that he has now lost “40 to 45 percent performance”. Dosed endurance training on the bicycle ergometer or the treadmill is still possible at the current simulated altitude of around 7,000 meters, says the 56-year-old. However, the two are currently stay well clear of the mobile climbing wall in the hypoxia chamber. “The strain on the muscles is much greater, and we get very quickly into the anaerobic phase. But we want to avoid an oxygen defiency that would cause immediately headaches,” says Ralf.

No cabin fever

I ask whether the relationship of the two test persons is put to a serious test by the long time in the hypoxia chamber? “Not so far,” Nancy replies, laughing. “We spend so much time together. There are no problems at all, and I don’t expect any.” Ralf nods. “I think it’s important to keep stress out of a relationship. We’ve done quite well so far.”

No Big Brother

Nancy and Ralf in the DLR hypoxia chamber

Even the constant camera surveillance doesn’t bother them anymore. “We’re not making  ‘Big Brother’ here,” says Dujmovits. “We know that the scientists are trustworthy with everything that can be seen here.” Meanwhile they almost ignore the cameras’ existence. “This morning I was just walking around the rooms in my underpants. Only on my way back I realized that everyone in the surveillance room could see me like this.” Ralf emphasizes that the whole experiment is “a team effort”. The climber specifically praises the committed DLR scientists: “They are here for us 24 hours a day in an all-round shift work.”  Nancy is also enthusiastic about the team. “All the staff here have been treating us so well. We feel really like a prince and a princess.”

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.

Ralf Dujmovits (l.) and Nancy Hansen in the still empty DLR living area

This seven-thousander has neither a summit, nor does it offer impressive views. It covers an area of ​​only around 110 square meters – and is located on the grounds of the German Aerospace Center (DLR) in Cologne. A hypoxia chamber within DLR’s medical research lab “:envihab” – the name stands for environment and habitat – will be comfortably furnished in the coming months.

Four weeks in the chamber

In mid-May, Ralf Dujmovits, the only German mountaineer who has climbed all 14 eight-thousanders, and his partner, the Canadian climber Nancy Hansen, will move in there for four weeks. They are taking part in a highly interesting hypoxia study conducted by DLR in cooperation with the University of Texas. The assumption: Although extreme oxygen deficiency threatens life, there could also be a positive effect on the body.

Stronger heart through hypoxia?

Ralf is wired for magnetic resonance imaging (MRI) …

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.

Now it is to be tested whether this effect also occurs in humans. For this purpose, Dujmovits and Hansen, both healthy, will spend two weeks in an oxygen-reduced environment comparable to 7,000 meters above sea level, as subjects of the pilot study. “We expect them as healthy, well-trained subjects to increase their cardiac output as well,” says DLR doctor Ulrich Limper during the first of several preliminary examinations in Cologne. For a further study, an experienced mountaineer is being sought as test person, who has already stayed at heights significantly higher than 7,000 meters and in addition has suffered a heart attack. He too is to spend two weeks in hypoxic conditions – of course only after he has completely recovered from the infarction.

Immediate termination possible

… and prepared for the examination of his brain

Ralf and Nancy first want to pre-acclimatize on the mountains in the Swiss canton of Valais and then go to the hypoxia chamber in Cologne in mid-May. In the first two weeks, the simulated altitude will be increased from 3,000 to 7,000 m by adding nitrogen and thus slowly lowering the oxygen concentration to eight percent (usually it is 21 percent). Over the last two weeks, Dujmovits and Hansen will have to hold out at the equivalent of an altitude of 7,000 m. Unlike in the mountains, however, the air pressure in the chamber remains constant, so that the experiment could be terminated immediately in case of complications.

“Completely crazy”

Blood draw from Nancy

He has done a lot of research and reading on the findings on long-time stay in high altitude, says Ralf Dujmovits: “In addition, my own experience of many nights in series above 7,000 m have led me to believe that the risk is within manageable limits. And if there are any problems, we can at any time press the red button and stop the study.” Nancy Hansen admits she has a queasy feeling. “Of course I am nervous about the risk! It’s completely crazy to live at the equivalent of 7,000 m for two weeks,” says the 49-year-old. “On the other hand, we can leave the study at any point if we feel too unwell. The bigger question for me is whether there will be long-term negative effects.“

Heart attacks in the family

Measuring the lung volume

Dujmovits had started studying medicine as a young man before fully dedicating himself to the mountains. The interest especially in high altitude medicine has remained, says the most successful German high altitude climber. “Being able to contribute to new findings in the field of myocardial infarction research is fascinating as well as exciting. Moreover, I have the opportunity to learn more about my body and its reaction to hypoxia.” Nancy Hansen agrees, adding family reasons for participating in the study: “My father had a massive heart attack 14 years ago. My uncle died of a heart attack. My young nephew has had two, 16-hour open heart surgeries. The topic is really important to me.”

Interesting for earth and space

This also applies to the DLR. “We are not just learning about the limits of the body of highly trained and specialized people who are comparable with pilots or astronauts and can serve as a study model for them, in our case Nancy and Ralf,” says Ulrich Limper, “but we also have the opportunity to improve the treatment of an acute heart disease, what would especially help the patients on earth.”