Working with freedivers and high-altitude mountaineers emphasises how precious oxygen is for the brain; it becomes especially clear when for example, some of the freedivers can hold their breath for over 11 minutes.
Understanding how they can achieve these remarkable feats helps shed unique light into what causes certain diseases of the brain, with a major focus on neuro-degenerative diseases like Alzheimer's.
Q. You're particularly interested in environmental extremes. Can you tell me about some of the other exploits you've been involved in, where the limits have been pushed?
A. Clinical work is challenging and it's a wonder how some patients survive against the odds.
For me, these are some of the most extreme human performers.
In terms of sports-related activities, I work with some of the best freedivers in the world and have assisted in numerous expeditions, not just to high-altitude but also to the South and North Poles.
I work as a consultant grant reviewer for Nasa and the European Space Agency too; there is a great deal of interest scientifically in getting astronauts to survive the return journey to Mars in good health.
Being physically active and keeping it together are key elements of success.
I also work with some Olympic athletes who "push the limits" on just about an everyday basis.
Q. You were also notably part of a group in Bolivia twhich reached the summit of the 6500m peak Nevado Sajama before playing football to demonstrate how females are better equipped to cope with the extremes of exercise and hypoxia. Why do you feel this area of research is so important? And how much of it are we yet to understand?
A. These very applied studies have allowed us to look inside the human brain and figure out how it works, sometimes for better sometimes for worse.
These extreme models have indicated that the female brain is better able to cope with the lack of oxygen at high altitude, much to the chagrin of the macho male counterparts.
They seem to be better able to defend brain blood flow and extract oxygen so that mental agility seems to function better.
We think this is the case because their blood vessels are floppier, that is less stiff, thanks to the fact that there are more chemicals floating around in the circulation that allow the vessels to open up and get blood to the brain.
This has given us some unique insights into what causes brain disease in later life, as we get older and as we became less physically active.
More oxygen means better quality of life; and exercise is a cheap, safe and effective tool to help with this.
I've also worked with diving seals and freedivers because they are so incredibly well-adapted to surviving for prolonged periods without oxygen; looking at some of nature's extreme performers has allowed me to study the fundamental mechanisms that gets oxygen from the air to the brain and ultimately why this promotes survival.
Rugby is a religion here in Wales - as indeed in New Zealand - and concussion is an interesting, albeit very applied model that has allowed me to dissect out whether brain inflammation predisposes to impaired mental agility and dementia in later life.
Again, it seems that any benefits gained through long-term rugby exercise training are effectively neutralised by repetitive head impacts, impairing a retired player's ability to get sufficient oxygen to the brain.
Q. On your expedition to Mt Everest this year: what was its purpose and had a trek to the summit ever before been mounted in the name of physiology before?
A. The purpose was to showcase the effects of extreme altitude on the body and by exploring why low blood oxygen levels cause impaired mental agility and its relevance to dementia in later life.
I was attempting to take the world's highest recorded measurements to understand how the brain communicates with the heart, lungs and muscles. Previous expeditions have taken samples before but not focused on this mechanism and not at such a high-altitude.
I also examined what happens during acclimatisation and why the brain's performance improves - not just the body's - as it "sees" more oxygen and what lessons can be translated into the clinical setting.
Q. During that expedition, you essentially saved the life of UK adventurer Richard Parks, who was attempting to reach the summit without supplemental oxygen and take the highest-elevation blood sample and muscle biopsy ever collected. What happened there?
A. I took blood samples from Richard and it became clear that he was making way too many red blood cells.
Though this is a natural response to the lack of oxygen and is an important part of acclimatisation, Richard's blood became so "thick" that it became a risk factor increasing his susceptibility to stroke or throwing off a clot.
Thus, from this point on, it was clear that any plans to climb any higher and "further acclimatise" above the Icefall - above 6000m - was too dangerous. My dictum is "safety before summit".
We were all very disappointed but the clinical decision to stop was unequivocally the right one.
The mountain isn't going anywhere and we'll be back.
Q. In terms of the equipment and sheer physiological demands, how would have Hillary's first ascent compared with those made regularly today? Is there anything to suggest it would have been a great deal more difficult?
A. You can see progression in just about every sport; records are always being broken and technology and preparation have a role to play.
Two things stand out for me when comparing the then and now ascents of Mt Everest.
Although cutting edge at the time, Hillary's equipment was nonetheless heavier and clothing less insulated compared to modern gear.
Thus, one could argue that the "oxygen cost" was somewhat higher and the risk of "cold injury" greater.
Furthermore, we lean on state-of-the-art medical technology which helps us hone our physiological performance.
For example, portable equipment that allows us to measure and optimise blood flow to the brain, heart and muscles using ADInstruments technology to integrate lots of different complicated signals can help determine when we are ready to summit, or are optimally acclimatised.
But above all that, the early chaps were pioneers, pushing the boundaries and taking their bodies and minds to places that had never been attempted before.
The psychological stress would have been far greater compared to today since there were many doubting Thomas' within the scientific community, fearing that the summit was beyond the limits of human tolerance.
With the exception of an "oxygenless" summit - first achieved in 1978 by Reinhold Messner and Peter Habeler - today's climbers are simply standing on the shoulders of these giants.
Q. Can you share a bit about what you're going to be discussing in Dunedin next week? You'd of course know concussion is quite a topical issue here in New Zealand at present. What do you make of contentious links that have been drawn between concussions and long-term cognitive impacts like early onset dementia?
A. I will be raising the profile of oxygen in the brain while at Dunedin; the molecule that made the world and the organ that makes us.
I'd like people to understand that we have evolved with brains that are oversized, inefficient gas guzzling energy hogs and that creates a problem whenever blood supply is challenged either by disease or other environmental challenges.
By looking at disease and high-performance athletes - both human and animal, including the turtle, which is ranked number one for me - and understanding how we get blood and oxygen to the brain, will ultimately help us figure out what causes brain disease, like stroke and dementia, and alternative ways of preventing or at least slowing this down.
Rugby is a fantastic example of two opposing forces that challenge the brain; the good of exercise which helps the brain develop and the bad of impact which over time, can actually take over the benefits and cause long-term complications.
It's a potential model of accelerated brain ageing and helps us look inside mechanisms of damage and repair.
Q. Lastly, are any of the findings you've made in extreme environments applicable to our everyday lives, and, if so, could you provide a few examples?
A. Patients face low levels of oxygen as a result of numerous diseases affecting the brain, heart and lung's circulation and this is especially evident in intensive care.
However, they face a whole range of other challenges - we call them co-morbidities - and this can muddy the water in as much as cloud to what extent the lack of oxygen itself is causing problems.
Studying how the brains of high-performance athletes like freedivers and mountaineers and animals like turtles and carps cope with the extremes of oxygen lack can ultimately improve our understanding of the mechanisms that limit human tolerance to oxygen deprivation and develop new "target" therapies that could ultimately save patients' lives.
• Professor Damian Bailey is visiting New Zealand as a guest of ADInstruments from next Monday, July 11, until Friday, July 22, to host a series of guest lectures. He's also a special guest at the New Zealand International Science Festival and will be talking about concussion in sport alongside Australian journalist Peter FitzSimons and Otago University's Professor John Sullivan at Dunedin's St David Lecture Theatre Complex on July 13. For more information and tickets, visit www.scifest.org.nz.
