UBC Okanagan Mount Everest Research Expedition 2016: The Story by Ryan Hoiland

Sometimes things in life come full circle sooner than we expect. In 2011 I was an undergraduate student at the University of British Columbia Okanagan. At this time in my academic career, I was quite honestly disengaged and truly at a cross roads where I desperately needed something to grab my attention and re-align my focus. Enter Professor Ainslie and his research program. At this time, October 2011, rumors were circulating that Prof. Ainslie would be leading a research expedition to the Nepal Himalayas to examine human adaptation to low oxygen levels. I vividly remember thinking to myself that maybe this was the break I needed, the academic substrate I required to re-ignite my passion for learning. As a young twenty year old man, admittedly still very naïve, I was luckily introduced to Prof Ainslie through a friend, whom I cannot thank enough today for facilitating my entry into research. As some would say, the rest is history… I went to Nepal in 2012 and upon my return to Canada and graduation from the Human Kinetics program I began my Masters of Science with Prof. Ainslie. Now as a PhD student in his lab, I recently took part in the more recent 2016 UBCO research expedition to Nepal. The end.

Wait! The story cannot end that fast! That would not do it justice, would it? Let us continue… Following my introduction with Prof. Ainslie in the fall of 2011 I began a research practicum in his laboratory. I remember spending as much time in the laboratory as I could, a human sponge absorbing every bit of information I stumbled upon. With the primary baseline study looming a mere day or two in the distance, I was asked to briefly leave the lab, while the research team had a private discussion. Standing in the hallway I thought to myself, had I made a mistake? Had I broken some equipment? What could possibly be so secret it required my absence to discuss? A few minutes later (although it felt like lifetimes) I was summoned back into the laboratory. To my surprise, and extreme excitement, I received an invitation to participate in the Nepal expedition! I said yes immediately. With my new sense of excitement and eagerness I returned to the lab two days later for a week of ~16 hour experimentation days.

The study I was now assisting with was pushing the envelope of human physiology research, and aimed to determine how changes in the oxygen content of our blood, as we would experience at altitude, affects oxygen delivery to our brain. Now, answering a question such as this is not a simple task. Specifics notwithstanding, the study involved catheterization of the radial artery (an artery in the wrist) and the internal jugular vein (a vein in the neck that drains blood from the brain). We needed a catheter in our neck… yes, our neck. Absolutely terrifying I thought. Who would subject themselves to such a study? Well, it was in fact the laboratory members that would be participating in this study – a group of modern day mad scientists that because of their passion for research and drive to “find the answer” conducted this testing on themselves. So I figured, why not? I could handle the so called “jug-line” and elected to participate in the study as well. Following completion of the dreaded jug-line study, the rest of the Nepal expedition went off famously, and was extremely successful.

Catching my breath at the end of the “jug-line” study in 2012 (left) and 2016 (right). The internal jugular vein catheter can be seen on the right side of my neck in both pictures. I like to think that my passion for science and easy going attitude are clearly evident by the “thumbs up” attitude that I have carried with me from 2012 through to 2016. Photo credit: Dr. Chris Willie

Fast-forwarding to 2016, where as a PhD student I would be involved in my second Nepal research expedition, things began to come full circle, and I gained a new sense of perspective from that I had in 2012. This time around, I had a serious job to do. Instead of merely helping out with the main study, it was my job to lead it, my main doctoral thesis study. As you can see in the picture above, I am holding approximately half a liter of my own blood, or the “house red” as our study physician called it. Why you might ask? Well, we decided to ask the question, how does the red blood cell contribute to regulating oxygen delivery to the brain when we have lower blood oxygen levels? Clearly the red blood cell is important as it carries oxygen around our body and delivers it to our tissues like a tireless postal service (brain, heart, etc.). However, there is some idea it also regulates how much flow is directed to different areas of our body, including the brain. In order to answer our question, we subjected ourselves to lower levels of oxygen using a computer controlled breathing system (simulating high altitude at UBCO) in our normal state, and then following a dilution of our blood, hence why my blood was removed and put into a bag. Simply put, the difference in how our body responded before we removed the blood, and after it was removed indicated how important the red blood cell is and let me tell you it is pretty important! This study was completed successfully and preliminary analysis has provided us with some invaluable information.

Alongside running my main thesis study, I was tasked with several large leadership roles for the overall expedition. Long days of ordering supplies, equipment, and then organizing everything into an expedition manifest were pushing my organizational skills to the limit. Had you seen how disorderly my workspace was at the time you may not have thought I was the best option for the job! However, we successfully transported approximately six tons of equipment to Nepal and the pyramid lab.

Following the safe arrival of our 37 member team and all our equipment in Kathmandu, the real excitement began. As opposed to 2012, where the chaos and proverbial buzz of Kathmandu was rather alarming, I exited the airport with a more seasoned sense of calm. I was back and I was excited. No longer the undergraduate student lacking direction and passion, I had matured, focused, and arrived with a sense of determination. Therefore, while impossible to replicate my initial introduction to Nepal, a greater sense of appreciation for who and where I was, alongside the opportunity to draw parallels between the two expeditions and self-reflect made the journey ahead one of both scientific and personal significance.

Cross-checking the equipment with the expedition manifest upon arrival in the Kathmandu Airport. Although I don’t vividly remember this particular moment, a colleague of mine, Dr. Chris Willie, jokingly informed me following the expedition that my level of focus is beautifully illustrated by the juxtaposition of my very still self and the blurred airport worker behind me. It was quite the relief when all the equipment arrived in one piece! Photo credit: Dr. Chris Willie.

Over the course of approximately one week in Kathmandu the rest of the crew and I spent our days managing a rather sporadic schedule of work, exploration, and gastrointestinal distress. Our testing on the high-altitude native population, the Sherpa, was just beginning. This line of inquiry was quite intriguing to me, as it provides a window into how humans evolve during low oxygen levels. Sherpa, to explain, have lived at high-altitudes for over 25,000 years, and as a result of positive adaptation perform exceptionally in the hostile low oxygen environment of the Himalayas. In truth, the Sherpa are the unsung heroes of Himalayas, and the backbone of most modern day expeditions. I was intrigued by the prospect of furthering our knowledge of why the Sherpa have become so fit for life at altitude. I wanted to know if the brain of the “oxygen adapted” Sherpa reacted differently to low oxygen levels than did the brains of us westerners upon ascent to altitude. This question was my focus throughout the ascent.

Top left is the beautiful Kathmandu Guesthouse courtyard, which we called home for a week prior to ascent. Ticket in hand we flew over mountain ranges sprinkled with villages until landing in the rugged and dangerous Tenzing-Hillary Airport in Lukla. Photo credit: Dr, Alex Williams and Ryan Hoiland

The ascent commenced by taking a flight to the most dangerous airport in the world, the Tenzing-Hillary Airport in Lukla, 2840m above sea-level and located on the side of a cliff. The runway is about 500m in length, and slanted at an approximate 12 degree angle. This apparently requires the pilot to fly below the level of the runway, so that upon the approach he or she may pull up and land the plane parallel to the runway. While not an expert, I understand that flying straight at a cliff until the final possible moments is not a fail-safe procedure. To add some perspective the runway at Kelowna International Airport is over 5 times longer than the runway in Lukla. Upon landing, we met with our Nepali coordinator, or Sirdar as they are referred to, Nima Sherpa (pictured below) to coordinate equipment, and a much needed meal and rest.

Nima Sherpa, our expedition Sirdar summited Mount Everest in the summer of 2009. While critical to the organization and execution of our expedition, Nima’s greatest trait may have been is ability to fill a room with laughter, always joking and boosting team moral. Photo credit: Ryan Hoiland.

The next 10 days involved trekking to Monjo (2800m), Namche Bazar (3400m), Deboche (3900m), Pheriche (4370m), and the Ev-K2-CNR Pyramid Laboratory (5050m). At each location we collected data, a struggle due to the variable and overall sparse access to steady electricity. Luckily, we had a well versed tradesmen on the team to keep our operation running. Namche is one of my favourite locations in the world. Sitting amidst the Himalayan mountain range, 3400m above sea-level, it is the epicenter of the Mount Everest trekking region. Drastically changed from 2012, it is now littered with cafes, bakeries, and pubs – for better or for worse. It is perhaps worth noting that without exception, no matter where I travel in the world I always stumble upon an Irish pub. This, I find, is quite remarkable, and perhaps influenced why the team and I were so fond of Namche (they had cold Guinness!). But in all honesty, Namche, and the Himalaya in general, were a welcome departure from the day-to-day grind we are so accustomed to at home. With a cup of burnt espresso in hand and my eyes focused on the breathtaking landscape surrounding me, I had not a care in the world.

Connor Howe and I receiving some supplemental oxygen during one of our ascent studies. Thumbs up for oxygen! Photo credit: Ryan Hoiland

Namche Bazar located at 3400m above sea-level is the largest village on the Mount Everest Base Camp trail. Built along the side of the mountain, this crescent moon shaped village felt like a metropolis in the mountains. Photo credit: Dr. Alex Williams.

Onwards and upwards, now breaking the 4000m mark, we arrived in Pheriche on day 7 of our trek. In general it is around 4000m where it becomes more-or-less obvious who will succumb to altitude illness. Given the impossibility of predicting who would get sick prior to ascent this made for a bit of suspense. Headaches were evident throughout the entire group, myself included, but no one had yet to progress beyond that. While near impossible to predict who will get altitude illness, the most telling sign, is whether or not you were sick in a previous trip to altitude. Therefore, the knowledge that I experienced negligible levels of altitude illness in 2012 kept me at ease, while I observed the rest of the team out of curiosity and concern.

Pheriche holds one of my fondest memories of the trip. We were in Pheriche on October 10th and October 11th, which were Mike Tymko and I’s birthdays. Following dinner on October 10th, we were each surprised with a birthday cake, that I have to admit was quite fantastic. As Mike and I were away from home on our birthdays the year prior as well, at the Barcroft Station, on White Mountain, California, it was nice to enjoy some festivities this year. Now believe me, a chocolate cake at 4000m above sea-level is about as festive as it gets when all you have eaten for the past 2 weeks is potatoes, lentils, and rice! It was an enjoyable night spent with some great friends.

Pheriche, 4371m above sea-level is a small village comprised of about 10 lodges and the Himalaya Rescue Association clinic. Photo credit: Dr. Alex Williams

At last, we reached the daunting task of our final ascent to the Pyramid Laboratory, trekking above 5000m. The steepest, and highest portion of the trek, I was ready to embrace the physical challenge. While I struggled immensely in 2012, I was in better physical shape in 2016, and ascended much easier, and without complete exhaustion.

The Ev-K2-CNR Pyramid Research Laboratory. Our arrival took place on a beautiful and sunny day. Photo Credit: Ryan Hoiland.

While the team took a moment to absorb the fact we had finished our ascent, I remembered back to my arrival in 2012. Exhausted, irritable, and completely unaware of what the future held. I chuckled to myself thinking, who knew I would be back again. Following this short period of calm, it was time to get back to business. It was but a small group of us, ten I believe, that actually arrived a day early with the task of setting up the labs. From that point onwards, it was long days, starting at 5am, and often ending at about 8pm, all the while carrying a little bit of altitude illness with us, which I might add feels quite similar to a hangover! We ran more studies on the, brain, heart, lungs, nervous system, skeletal muscle, and our blood vessels. Every day was unique in its own way, whether it was due to a power outage, a meal other than dahl baht, or an electrical fire. Now, given we were at a fairly high-altitude, team members began to intermittently battle bouts of rather debilitating altitude illness. Unfortunate for one member of the expedition, their symptoms did not resolve despite treatment with altitude medication, and they had to descend – the only true treatment for altitude illness. So for three weeks we worked away, completing a multitude of studies with a fantastic success rate. At the end of all the hard work was a day scheduled to explore the Khumbu region, trekking to both Everest Basecamp and to the top of Kala Patthar (pictured below).

Setting up the transcranial Doppler ultrasound in our study, which looked at the role of the red blood cell in oxygen delivery to the brain at altitude. Pictured with me is Matt Rieger (left), Alex Hansen (back middle), and Connor Howe (right). Photo credit: Dr. Alex Williams.

Exploring Kala Patthar (5650m) in 2012 (left) and 2016 (right). Photo credit: Ryan Hoiland

The view atop Kala Patthar is an unforgettable one. Standing there, my gaze fixated on Mount Everest, everything else felt so small and insignificant. Detached from everyday societal burdens, I got to enjoy the beauty of our wonderful world.

Looking from Kala Patthar onto the Khumbu icefield and Mount Everest in the background. It was a perfect day for our trek. Photo credit: Daniela Flück.

The 2016 Nepal expedition was an amazing experience, and invaluable to my progression as a PhD student. Since our return, several team members have already submitted their research for publication. I am almost there too! In fact, nearly every student from the expedition presented their research that the International Hypoxia Symposium, in Lake Louise, Alberta, in February this year (2017). It was an amazing conference and platform for us to showcase the work we had just conducted. I was lucky enough to be awarded 1st Place for best oral presentation by a junior scientist, for my presentation on how the red blood cell is important in regulating oxygen delivery to the brain. While we are still working with the mountain of data we collected in 2016, our eager and inquisitive minds are already looking forward to the next adventure!

Josh on Becoming an Author

End-Tidal forcing and Echocardiography

Echocardiographic measurements during exposure to hypoxia

My first lead author publication! A sexy paper on hot physiological topics. By mitigating hypoxic pulmonary vasoconstriction with the administration of acetazolamide, can we prevent intrapulmonary shunting? Nope, shunt vessels appear to be hypoxia-mediated. Insightful and innovative, although unfortunately data collection preceded my arrival. My contribution included data and statistical analysis and the drafting of the final manuscript now accepted for publication in the Journal of Physiology. As a naïve MSc student at the onset of this project, I now feel more comfortable with the scientific method and the processing of scientific data. My first forage into scientific data analysis and writing was difficult but I now find it much more manageable to decipher scientific literature and to work with complicated analysis software. The single greatest challenge faced writing the manuscript was how to interpret an unexpected finding. Enter acetazolamide, a drug that most notably ruins beer by eliminating “the tingle of carbonation” by slowing the conversion of carbon dioxide. Unconcerned with the subject’s post-study pub experience, our team of researchers used acetazolamide to blunt the rise in pulmonary artery pressure typically observed with hypoxic exposure. Intrapulmonary shunt vessels tend to be dormant in resting conditions breathing room air and were once theorized to act as pop-off valves, being popped opened by elevated pressures. Another possibility was that hypoxia sends a biochemical signal that promotes blood flow through these vessels. The elegance in this study, as you can hopefully appreciate, was that administering acetashunt study zolamide permitted the observation of hypoxia without the accompanying rise in pulmonary vascular pressure. Methodological separation of proposed stimuli: classic mechanistic physiology. Unbeknownst to the research team, the subjects were low responders to hypoxia, meaning they displayed only modest increases in pulmonary artery pressure. With modest rises comes modest blunting and a modest difference between trials, making interpretation tricky. Check out the article to see how these findings were addressed and let us know if you agree or disagree with our interpretations. As for me, well it’s about time that I get my hands dirty in the lab and start working on my thesis!

Josh Tremblay

Chris in Croatia: Researching Prolonged Apnea in Breath-hold Divers


I love in passionate people the mutual ease with which a grand plan is hatched.

I received an email some months back from just such a person, a normal email requesting a PDF of a paper, which quickly blossomed into a conversation on shared interests, specifically aspects of cerebral blood flow (CBF) and its regulation during prolonged apnea in breath-hold divers. Prof Zeljko Dujic is one of the world’s greats on all aspects of diving (amongst other things) and is motivated, to say the least. Now I’d love to say that I immediately associated the Dujic name with all of his key papers and findings but that would be a lie. Rather I quickly perused the papers I vaguely recalled and got the email conversation rolling… and a good thing, because the project we ended up recently completing was in every sense amazing.

Why are breathe hold divers so interesting? Basically because they can do something that no one reading this is able to do (unless you happen to be a breathe hold diver, I suppose). “Prolonged apnea” is a relative term, in my case a whopping 90 seconds (maybe), but in these athletes the act is a very different story, and a very interesting physiological phenomenon. Training for a variety of events ranging from static apneas whilst floating face-down in a pool (current world record: 11 minutes 35 seconds!) or No-Limits where using a weight to descend well past the photic zone of the sea, and a balloon to return to the surface (current record: 214m!) such athletes can remain conscious into levels of hypoxemia much lower than the average person can endure – meaning that if you attempted such a study (not that you’d get ethics to do so) with the use of a thick plastic bag and your fellow grad students there’d likely be a few fewer grad students standing around drinking coffee. Herein lies the tremendous opportunity to study in Prof Dujic’s lab, along with Croatia’s national apnea coach Ivan Drvis, and his athletes.


My interest (and thesis) is in the regulation of cerebral blood flow, particularly in the context of this regulation by changes in arterial blood gases (oxygen and carbon dioxide). During a prolonged apnea, arterial content of O2 decreases and CO2 increases — each of which drive vascular dilation in the brain and a consequent increase in CBF. During a prolonged apnea in a trained apnea diver, arterial blood gases change far more than in any conventional setting, indeed, far more than can be driven experimentally in the lab (or at least what can ethically be achieved in the lab, clearly its possible to give someone pure nitrogen to breathe). In fact these divers don’t breathe for so long that were they an average person to breath-hold that long (read: duct tape), the O2 content in their blood would render them unconscious very quickly; ergo, these divers must adapt, of have adapted, or perhaps be predisposed to such tolerance. So on the one hand these athletes are not “average” people – not the usual “random sample” – but this is precisely what makes them so fascinating: their peculiar tolerance to hypoxia.

Fig. Schematic depicting gold-standard measurement of cerebral metabolism. Duplex ultrasound of the (A) ICA and (B) VA for regional CBF quantification, that, combined with measures of brain venous blood from the IJV.

Because different areas of the brain are responsible for different functions, and because some of these functions relate to cardiorespiratory regulation (i.e., heart, blood pressure and breathing), regional differences in blood flow in the brain is of interest during any challenge to the cardiorespiratory system – such as exercise, orthostatic changes (e.g., standing up from sitting), myriad disease states, or…. breath-holding. It would be therefore be interesting enough to study regional CBF (using Duplex ultrasound of the internal carotid and vertebral arteries, see Figure) during a prolonged apnea, but our plan goes further.

I should digress at this point and address one of the fun sides of science – the continually evolving idea, which gives the continually evolving plan, which if you’re not careful will typically manifest in the ridiculously complicated multi-hypotheses 5-hour protocol that cannot possibly be completed in less than 8 hours. Now I call this a fun side of science because I like a little chaos – if everything is so obviously feasible and there’s no chance of something going wrong than where’s the excitement in that? Human physiology is full of these things – the human element twice over: once from the physiologists who want to answer as many questions as possible in a given experiment, once from the consequent requirement for a large research team, and once more because you’re studying people. I suppose that’s three times the human element, the more the merrier. But fast-forward a couple months and the day of the study we finalized the protocol to a much more simple format – that which I describe here – focused on two distinct hypotheses. In the end you must get as much out of a study as possible, but not so much you get nothing!

Another characteristic of breath holding is that if the apnea is sustained long enough the respiratory muscles begin to contract involuntarily. These involuntary breathing movements (IBM) seem to augment CBF during a breath hold – each contraction produces a surge in venous return, cardiac output and arterial pressure and CBF gets a transient boost too. Now this may be good for cerebral oxygenation but to know the effects of IBM per se you must isolate the effects of the apnea induced changes in blood gases from the apnea (and consequent IBM). Another issue is that blood gases are often estimated from end-tidal gases – a sample of gas at the very end of an expiration that largely reflects the partial pressure of the blood leaving the alveolar vasculature (arterial blood). Clearly this presents a methodological problem if the subject is holding their breath… enter rapid arterial blood sampling.

We insert a catheter into the diver’s radial artery and take a small blood sample each 30 seconds of the breath hold. To assess the effects of apnea and IBM versus the hypoxia that results from apnea we will use a system (the ‘AirForce’; thanks to the computational genius of Dr. Glen Foster) that adjusts the inspired fractions of O2, CO2 and N2 to “target” a specific arterial blood gas profile – as close as possible to the same profile elicited during each person’s own apnea. Beautiful!


David in Nepal. [click to enlarge]

Because we decided to use the AirForce, and because we wanted to measure flow through both the internal carotid and vertebral arteries, and probably also because Prof. Phil Ainslie wanted another student somewhat less manic than me (never a bad plan), Anthony Bain was invited. Now given that Tony has enough going on at the moment to keep him busy with twice the hours in the day, and given that he ended up being totally instrumental to the study’s success, I owe him an unprecedented amount of beer. A pity he will no doubt at some point read this ‘blog’.

An equally fortuitous addition to the team was Dr. David Macleod – anesthesiologist at Duke Medical Clinics, NC, USA. David is an outstanding individual who can tell a story as well as he inserts a jugular venous line (we know, we’ve received both) and who’s calm, commanding demeanour is the type you have faith could not be rattled – which is especially comforting if he happens to be placing a catheter in your neck at 5050m in Nepal…

The Monastery

I hate packing. When we went to Nepal a year ago or so I theoretically headed all the packing from the UBCO side (I say theoretically because there were plenty of heads looking over my shoulder, and for good reason too, there are practical reasons of competency I hate packing) and managed to not forget anything crucial. I make lists. Iterations of lists that are revised, finalized, printed and finally ignored. I am the same with packing for climbing trips… I can have lists with all necessary items but come packing time I need to see everything laid out in front and gauge from there if I have everything needed. Totally illogical and wrought with problems but with Tony’s help we managed to forget nothing essential. Phil, Tony and I packed all these items – basically an entire lab – into the well-used Pelican cases and we headed to the airport. Twenty-four hours later we rolled off the plane into Split, where fortunately Zelko was waiting to talk the customs agent into letting us through unmolested with a more than $200K in equipment. A couple hours later we were tucked into our Monastery beds for a few hours of sleep before our jet-lag woke us up at 4 am. Wait – Monastery? Originally Zeljko set Phil and I up in the rooms across from his lab but through the planning process when first Tony and then David was added to the roster we needed more space. A 10-minute walk from the lab is a Monastery (the kind with Monks… A rather large language barrier and an unfortunate ignorance of religions in general on my part preclude further detail on the topic. They do supply some excellent wine, however) on the top floor of which we were housed.

Split housing

Our windows looked into the back courtyard and garden of the neighbouring house: olive and pomegranate trees, rows of veggies, and the odd vestigial farming remnants decaying into the ground. Between us and the mountainous Dalmation coastline running south in a craggy crescent of white limestone, arid scrub brush juxtaposed against the blue Adriatic Sea, are the porous concrete blocks of government-built apartment buildings typical of Eastern Europe, the residual architecture of a recently socialist country. The sunrise basks the islands to the west in hard orange and I look forward to getting caffeinated.

Ivan Drvs is the Croatian national apnea coach and has handled all of the subject recruitment. Getting volunteers for a study is an obviously pivotal aspect of every study and typically takes up a disproportionate amount of time; Ivan’s participation was totally essential to this study. Over the 12 days of data collection only one subject cancelled, and fortunately this was on the first day because it took the entire day to set up the lab. This basically consists of plugging everything in, getting Labchart (the data collection software) set up and calibrating the AirForce but there are always obstacles. Phil and Tony took care of the latter two – no small feat – and we were good to go by the end of the day, and had time for a quick tour of the nearby neighborhood next to the coast.

Our first subject on Day 2 was Goran Colak who a week prior had broke the world record for an O2-assisted static breath hold: he breathed pure oxygen for around 20 minutes and then held his breath whilst floating face down in a pool for 22 minutes! Colak (pronounced Chol-ack) is quite a sensation in the free-diving world at the moment, and arrived with a documentarian cinematographer who was producing a film about him. Perhaps for good reason as he seems to break every record he goes after, and anyway, held his breath for 7 minutes 45 seconds. Quite the first subject.

There are always teething issues in every study but with a few minor mistakes during this first test the rest of the study really went very well. We tested a minimum of two people each day completing a total of 17 tests by the end of 12 days. Seven of these were replicated in the same individual after they had consumed indomethacin – a prostaglandin inhibitor that reduces cerebral blood flow by about 30% – allowing us to assess the role of CBF per se in breath hold time and response to progressive hypoxia.

The photos and captions below should give a better idea of what data collection was like:


  • The experimental set up. Clockwise from left: Ivan Drvis, coaching the subject through the breath-hold; Phil Ainslie, watching the data come into LabChart he is responsible for the timing of the experiment, ensuring everything is running (you would be surprised how easy it is to ruin a trial by forgetting to turn on the finipres measuring blood pressure), and communicating between the scanners, blood extractors, and Ivan; Dennis Madden, Zeljko’s PhD student expert in SCUBA diving physiology, Petra Zubin, MD and soon-PhD of diving physiology; Chris Willie (me) measuring vertebral artery blood flow; Anthony Bain measuring internal carotid artery flow.
  • By the end of the breath hold every athlete is at his or her limit; maximum apneas require a great deal of psychological resolve.

    Breaking point

  • Radial arterial catheter for repeated sampling of arterial blood.

    Radial artery line

  • Hypoxia is profound when its color shows the desaturation of arterial blood!

    Blood sample range

  • End of apnea (left) versus pre-apnea.

    Blood contrast

Having just returned from the trip I now face analysis. We analyze our ultrasound videos using custom software that tracks the vessel walls of the artery we scan, but this process takes about 3-4 times as long as the length of video. Suffice to say I have many late nights ahead… But before we headed back Tony, Phil and I spent two days climbing on Hvar Island off the coast of Split. Beautiful conglomerate cliffs with chunks of polished marble made for technical steep climbing and we swam in the clear the Mediterranean and drank the local Ojusko to cool off in the evening.

Sunset in the Mediterranean

In sum, the trip was a tremendous success. We collected what are probably the most hypoxic arterial blood samples ever collected in healthy humans (including some collected above 8000m!) and had some fun doing it, started what looks to be a great collaboration with Prof. Dujic’s lab, and finally enjoyed a few days climbing and relaxing in a beautiful place.

In the coming weeks I will be putting my head down to complete the data analysis and then write the manuscript as I aim to finish my PhD by the spring.

–Chris Willie, PhD Candiate