Nature Newsblog

Members of the Caudwell Xtreme Everest expedition, testing human adaptation to hypoxia on the roof of the world, write a diary blog for Nature from 30 March, 2007.

The South Col (Camp 4), at 7950m above sea level, is the most inhospitable place I have ever been to.

It lies as a saddle between the peaks of Lhotse and Everest. Wind funnels through this gap in the mountains continuously, scouring snow from the ground and projecting it horizontally at high speed. A number of tents are normally to be found huddled together at the bottom of the route which leads up to the summit of Everest.

Traditionally climbers arrive at the South Col, from camp 3, in the early afternoon. They rest and brew up drinks until early evening when they leave for the summit. On their return the camp is dismantled and the climbers descend as rapidly as possible. The aim is to spend as little time as possible on this litter strewn wasteland. Our aim was to set up a physiology laboratory on the Col, and spend a number of days trying to study as many of our investigators as possible.

Continue reading "Everest: The South Col and beyond" »

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The Everest team, including Dan Martin who has been writing a diary of the trip for Nature, have made it successfully to the summit:

The Caudwell Xtreme Everest Team are pleased to announce that Mike Grocott, Sundeep Dhillon, Chris Imray, Dan Martin, Nigel Hart, and Dave Rasmussen summitted Everest from the south side at 06.30 this morning (Nepal time). They were joined by Pema Tharki Sherpa, Mingma Tsiri Sherpa, Thundu Sherpa, Pasang Tenzing Sherpa (all brothers), Tshering Pemba Sherpa, Pema Chhiring Sherpa, Tashi Sherpa, Pasang Nuru Sherpa, Ongda Gyalzen Sherpa, and Dendi Sherpa. They are all now resting at Camp Four at the South Col.

Michael Brown, Vijay Ahuja, and Maryam Khosravi are also at Camp Four, and they have been joined by Paul Gunning, Roger McMorrow, Mick O’Dwyer, Jeremy Windsor, and Andre Vercueil. These five climbers moved up from Camp Three half way up the Lhotse face today.

Denny Levett, Patrick Doyle, and Graham Hoyland have remained at Camp Two, and were instrumental in keeping communications going between the climbing team and the rest of the mountain during the summit attempt last night. They have also continued to care for an injured climber, who is awaiting evacuation to base camp.

Watch this space for more details once they've got their breath back!

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Members of the Caudwell Xtreme Everest expedition, testing human adaptation to hypoxia on the roof of the world, write a diary blog for Nature from 30 March, 2007.

Having completed our week long research programme at Camp 2 on Mount Everest (6,400m) the climbers have decided to come down low for some well earned rest. The remainder of the Caudwell Xtreme Everest (CXE) investigators continue to work testing all the trekkers that come through the four laboratories in Nepal (Kathmandu, Namche Bazaar, Pheriche and Everest Base Camp).

We are over half way through testing the trekking groups now and data collection has gone extremely well thanks to the effort of the teams at each laboratory. Altitude illness has been minimal on account of the slow ascent profile the trekkers take which means we have been able to test nearly every subject on the cardiopulmonary exercise (CPX) system. The volume of data from the 200 volunteer trekkers and our group of 24 investigator/subjects will be vast. I foresee a busy time ahead analysing the data, a task that will no doubt take a number of years to complete.

Continue reading "Everest: The rest before the final push." »

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Members of the Caudwell Xtreme Everest expedition, testing human adaptation to hypoxia on the roof of the world, write a diary blog for Nature from 30 March, 2007.

A number of the Caudwell Xtreme Everest (CXE) Investigators have just safely returned from a week of working at camp 2 on Mount Everest, in the Western Cwm – 6,400m above sea level. Whilst there we managed to perform a large number of studies under very difficult conditions. The temperature fluctuations experienced at base camp were magnified and now we had to worry about added dangers of heavy snowfall and avalanche.

We took venous and arterial blood to look at haemoglobin, haematocrit and gas partial pressures. We were genuinely shocked by the partial pressure of oxygen in our arterial blood at this altitude; values lower than I’d ever seen during my years working with critically ill patients on intensive care units. Yet we were still able to function normally and carry out complex tasks, including stripping and rebuilding the blood gas machine on site!

Many studies were completed at Camp 2, such as the highest ever breath-by-breath cardiopulmonary exercise (CPX) tests, neuropsychological tests, body composition and nutritional studies, brain Doppler, sidestream darkfield examination of the sublingual microcirculation, spirometry and a comparison of different supplemental oxygen circuits during exercise. By the end of the week the entire team was exhausted and ready to come back to base camp for a well earned rest. Unfortunately to get down to base camp meant once again picking our way through the Khumbu icefall. In the week that we had been up at Camp 2 huge sections of the icefall had collapsed which meant the Sherpas had to seek a new route through. A sobering reminder that everything beneath us is slowly moving downhill and that at any moment a big movement could either engulf or crush us as we attempt to scale this giant mountain.

Continue reading "Everest: Science from the Western Cwm" »

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Members of the Caudwell Xtreme Everest expedition, testing human adaptation to hypoxia on the roof of the world, write a diary blog for Nature from 30 March, 2007.

We have now been in Nepal for a month and are beginning to set up one of our laboratories high on Mount Everest. This laboratory is situated at Camp 2 (6,800m) in the Western Cwm and will be home to the investigators of the Caudwell Xtreme Everest project for the following week. But before I set off to great heights, here’s some more explanation of what we’re trying to find out.

As lowland residents travel to high altitude they are exposed to increasing levels of hypoxia. The physiological response to this insult is known as acclimatisation and our current understanding of it consists of a number of processes which together increase systemic oxygen delivery. Changes such as hyperventilation, tachycardia [fast heart rate], increased cardiac output and increased red blood cell mass all ensure that as much oxygen as possible is extracted from the rarefied air and passed on to the metabolising tissues which require it. We have known about this adaptive process for many years and its subtleties are detailed in many well respected texts. But what if this increase in oxygen delivery is not the whole story? Perhaps there is more to the process of acclimatisation than we had previously thought.

Continue reading "Everest: Logistics in a harsh environment." »

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Members of the Caudwell Xtreme Everest expedition, testing human adaptation to hypoxia on the roof of the world, write a diary blog for Nature from 30 March, 2007.

Here at Everest Base Camp in Nepal the science continues to flourish. It is a strange environment in which to work but after some time you do get used to it. We are living on glacial moraine created by the mighty Khumbu glacier. At night as we try to sleep the only sounds that can be heard are that of the ice creaking and snapping below us and avalanches crashing down the giant rock faces above us. In front of our camp lies the Khumbu ice fall, the tumbling face of the glacier that drains from the Westen Cwm, a snow bowl created in the rock horseshoe of Everest, Lhotse and Nuptse. In the morning it is somewhere between -5 and -10 oC, by lunchtime inside the laboratories it can reach nearly 20 oC. These conditions are very challenging for both investigators and subjects.

We have basically built ourselves a small village up here in the mountains. About forty little tents surround the central hub of the Caudwell Xtreme Everest project. We have laboratories constructed from shelters used in the arctic by the military. These laboratories are where we carry out our work into how humans effectively adapt to the hypoxia of high altitude. There are three cardiopulmonary exercise (CPX) systems in continuous use, on which we are cycling daily whilst measuring oxygen consumption and carbon dioxide production on a breath-by-breath basis. Most exercise laboratories at sea level have only one such system in place; to have three running simultaneously at 5,300m above sea level has been no small feat.

Continue reading "Everest: Logistics in a harsh environment." »

Posted by Nicola Jones at 02:10 PM | Permalink | Comments (1) | TrackBacks (0)

Members of the Caudwell Xtreme Everest expedition, testing human adaptation to hypoxia on the roof of the world, write a diary blog for Nature from 30 March, 2007.

We have now completed our trek to the base camp of Mount Everest at 5,300m above sea level. It is a harsh environment in which to live, let alone carry out complicated physiological protocols. During the day the temperature reaches about 20 oC yet at night it falls below -10 oC. This means that there are huge temperature fluctuations within our tented laboratories. Needless to say, the sensitive equipment we are using to study our subjects does not appreciate this daily freeze-thaw cycle. Keeping the equipment happy in this environment is a full time job!

Continue reading "Everest: Arrival at base camp" »

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Members of the Caudwell Xtreme Everest expedition, testing human adaptation to hypoxia on the roof of the world, write a diary blog for Nature from 30 March, 2007.

Sat in the Namche Bazaar Bakery Nepal with some particularly fine apple pie, I watch with amazement as our 20 tons of equipment slowly makes its way up the Khumbu Valley. Exercise bikes, tanks of gas, centrifuges, an arterial blood gas machine and over a hundred litres of liquid nitrogen snaking their way along the path courtesy of the local yaks and porters. Such a caravan is quite a sight even in this part of the world; a place where the bizarre becomes an everyday occurrence after spending enough time here. There aren’t many other places where you’ll see people walk past you carrying a freezer or a washing machine on their back as part of a day’s work.

All this equipment is currently being moved from its former home in London to six semi-permanent physiology laboratories in Nepal spanning altitudes of 1,300 to 8,000m above sea level. This huge logistical challenge will form the foundations for the Caudwell Xtreme Everest project, the largest high altitude volunteer study ever to be undertaken. Its purpose is to study the process of adaptation to the hypoxia experienced at high altitude in a large group of volunteers as they trek up the Khumbu valley to Everest Base Camp at 5,300m.

Continue reading "Everest: Strange things are afoot in the Khumbu Valley." »

Posted by Nicola Jones at 12:26 PM | Permalink | Comments (0) | TrackBacks (0)

A team of doctors, scientists and mountaineers are attempting to summit Everest this spring. As if that weren’t hard enough, they’re taking an exercise bike with them.

Together the group hopes to take some novel measurements of the blood’s oxygen content at high altitude, to understand more about the body’s response to hypoxia. The data they gather should help in the treatment of critical care patients down here at sea level, who also have problems shuttling enough oxygen around their bodies.

Today the group writes to Nature from Namche Bazaar, the village that serves as gateway to the high Himalayas. And they’ll keep sending us reports as the expedition continues; check the Nature newsblog for the science team’s diary entries.

For more about the science behind this expedition, read our news story from October 2006.

And find out more about the project on the Cauldwell Xtreme Everest site.

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