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Sunday, 17 July 2011

Extreme exercise fatigue on Finlayson: my blood sugar and my brain

On Saturday, during the Mt. Finlayon Madness competition, a colleague and I hiked to the top of the mountain and 'prototyped' part of our High-Altitude Brain Function on Kilimanjaro experiment.  Throughout the day, I ran up and down the mountain as a participant in the competition. Each time I reached to top of the mountain, my colleague, Megan Yim, went through the procedure of measuring my blood glucose, blood pressure, heart rate, EEG, and ran me through some of our computer-based cognitive evaluation processes.  The weather was perfect for debugging our examination procedure; it rained most of the day and we had to come up with ways to keep the equipment dry. These wet and cold conditions helped reveal weaknesses in our data collection paradigm and presented us with an opportunity to creatively shore up these weaknesses.

In addition to providing for an 'alpha-test' of our high-altitude paradigm, it also revealed to me how my body responds to extreme exercise fatigue. This race gave me an opportunity to push my body harder than I have in the past.  It wasn't the ascent and decent of Finlayson that was the real challenge for me (says my ego); it was the fact that I did it during a fast. The morning before the race I drank about 1 litre of chocolate milk to get me going before arriving at Finlayson.  Other than that, I didn't consume any calories until about 3pm that afternoon.  Of course, I drank as much water as needed.  Doing this helped to simulate a physically and mentally strenuous activity and I had to work really hard to get to the top of the mountain.  The first thing that I learned is that I am truly a competitive person. I didn't like fasting and watching other people eat cookies, while they pass me on the way up the mountain.  It wasn't so much that they were eating cookies in front of my that bothered me;  it was that I incapacitated myself enough that I couldn't keep up to some of them.  Yes, my ego took a beating. Upon my 4th ascent up Finlayson, I was in hurting;  I imagine that this is similar to what I'll be facing over a multiple day ascent to the top of Kilimanjaro. On Mt. Kilimanjaro however, it won't be blood glucose that will be in short supply-- it will be oxygen.

During this prototype experiment, I discovered that what I eat and when I eat during high-level physical output has a very profound impact on me and I'm now wiser having had this experience. However, there was a time in my life when my wisdom was lacking.  When I was in high-school I used to play rugby.  I played as a back; they put me on the wing.  It was my job to run as fast as I could, keep slightly behind the other backs with the ball, and when the time was right, they would pass the ball to me and I would score on the other team.  At least, that was what was supposed to happen.  For me, whenever I got the ball, I would usually not make the best decision about where to go to get between the other players and score.  It always seemed like I couldn't think and run hard at the same time. It seemed strange to me that I had difficulty thinking while I was running with a ball, attempting to doge my opponents, to score points for our team.

Some personal insight as to why I might have had difficulty thinking clearly while playing rugby when I was in high school came when Megan and I were on Mt. Finlayson.  After my first ascent up the mountain and during my fast, my blood sugar was in the low range (the "you should probably eat" range"). I had difficulty with our cognitive tests; I felt cold and distracted.  After my second ascent up the mountain, my blood sugar actually increased a bit to a range were I felt like myself; I felt pretty good. And I did OK on our cognitive tests. This was also the case for my 3rd ascent up the mountain.  On my 4th ascent, I felt terrible.  I really had to push myself hard; it wasn't my legs that were the problem, it was that I was felling terrible from the inside; it was really difficult to move forward. But I did-- I had food waiting for me at the top of the mountain.  When I reached the top, we collected my info:  my blood sugar was very low and my cognitive test scores were terrible.  After collecting data, I gorged myself on cookies, chips, and scones. This is where I learned something about my rugby days; when we measured my blood sugar again about 20 mins after eating, it was very, very high. While my blood sugar was high, I did our cognitive tests and did terribly. Maybe eating Jello before each game didn't help with my decision making during rugby games.

Interestingly, after the next descent and subsequent ascent, my blood glucose returned to the normal range and my cognitive exam scores were great.

When we ascend Mt. Kilimanjaro this Fall, it will be the oxygen that is in short supply.  During conditions of low air-pressure, our brains will not function as they should and we will likely feel a fatigue similar (or greater) to what I felt on my 4th ascent up Finlayson while fasting. I'll be able to give you a comparison of a glucose low and an oxygen low very shortly; some of us are headed up White Mountain (4344m altitude) this week to find out what a short high altitude exposure is like.  Interestingly, we can drive up to 3560m before going for a hike to the summit.  I have a feeling we're going to be hit hard by the altitude given that we will have basically no time to get used to the altitude.

Overall, our high altitude endeavors are to add to our understanding of the cognitive effects of mild anoxia, and to our understanding of the impact this has climbers and mountaineers. Our planned Kilimarjaro study will be used to inform a larger study for the purpose of developing recommendations for high-altitude adventurers to detect impending problems at higher altitudes and perhaps even optimize training in order to preserver decision making.  We will continue to post information pertaining to our preparation and our actual trip up Kilimanjaro over the months to come.

1 comment:

Jayna Brulotte said...

This is amazing! A friend of mine, who was at the Madness on Saturday, posted your video, and i was like 'hey, i've met that guy before!' (at a party of Cheri's a while back). Your work sounds very interesting. The Kilimanjaro climb will be an amazing experience, no doubt. Hope that you are doing well!