Tuesday, March 6, 2018

KSI Results: Part 1

I got my results back from my testing at the Korey Stringer Institute at UConn and to say I learned a lot about my body would be an understatement. Not only have I been racing and training for triathlons for a number of years now, but I work in this field too, so it's important that I keep myself knowledgable about the many aspects of this sport. I've been following general protocols for nutrition and hydration, specifically for the ironman distance, because that is the main discipline that I train for, and it is the one that requires the most attention to detail. I've even worked with a nutritionist to dial in my race day fueling strategy, but even that wasn't enough.

I've had some decent results in the first 4 ironman races that I competed in. I qualified for Kona, had a few podium finishes, and some relatively speedy times as well. When I DNF'd Ironman Los Cabos this past November, it forced me to have to address some of the issues* I'd been facing if I wanted to continue racing.

*Issues are outlined in previous blog post (bloating, swelling, hyponatremia).

I visited the Korey Stringer Institute in January to go through some testing in their brand new Heat Lab. The first day of testing consisted of a Substrate Utilization Test on the bike to determine how many calories I'm burning at different intensity levels (levels determined by power output, heart rate, and perceived exertion) and what percentage of fat vs. carbohydrate I burn at each level. Most endurance athletes rely primarily on burning fat for fuel (especially at low intensities) because it is a more efficient, longer lasting fuel source. I have always thought that my body was more well-suited for shorter, faster races because of my background playing anaerobic, high intensity sports, and now I have the proof for that right here in this graph:

I'm a sugar burner. There are no points in this graph, even at low intensities, where I rely primarily on fat for fuel. Granted, I did this testing during the time of the year when I'm the most de-conditioned, so I might become more efficient as I increase my fitness, but this data definitely doesn't scream "ironman athlete." Regardless, I am an ironman athlete in my heart and soul, so my body is just going to have to deal with that. The Substrate Utilization test is only a small piece of the puzzle, and while this information will help me determine my caloric intake for races, it doesn't explain the bloating and swelling that I undergo while I'm racing.

Substrate Utilization Test

At the end of Day 1, I picked up my "temperature pill," and started a 24 hour diet log and urine collection, which meant I was going to be walking around carrying a jug of my own pee. No one ever said this was a modest sport. I then set an alarm for 2:00am, when I was supposed to wake up and take my "temperature pill," which was actually a tiny thermometer that we needed to be sitting in the upper part of my intestines by the time we were going to begin testing later that day. If I took it too late and it traveled down to my stomach, the temperature readings would be thrown off by my fluid intake during testing. If I took it too early, we would risk me pooping it out. The risk was high for this timing because if I missed the window, I'd be doing 3 hours of testing with a rectal thermometer.

I prayed to anyone who was willing to listen, set a whole bunch of alarms, and showed up the next morning with my thermometer right in place. For the Sweat Rate & Electrolyte Tests (both bike and run), I had to drop off my clothes the night before to be washed free of electrolytes, and the first thing I had to do upon arrival was take a shower with no soap or shampoo, and try to wash any tiny amount of anything that could simulate an electrolyte off my body... and then not put on anything afterwards, like deoderant, or moisturizer. #sacrifices

We then took my weight, and I got on the bike in the 96 degree, 60% humidity Heat Lab, aka indoor Kona. The goal was to ride at Ironman intensity for 2 hours, to determine how much sweat I lose (in fluid and electrolytes) in those conditions, so that I can replace what I lose, accordingly. Since we knew that my previous nutrition and hydration plan that I had in place for Cabo didn't work, we decided that I should just drink to thirst during the session. That ended up being a good plan because I ended up replacing my fluids at an ideal rate to which I was losing them (athletes should ideally be replacing 70-90% of their fluid losses during activity). We also had an idea going into this that I had a low sweat rate, and we confirmed that as I lost only 1.3L/hour in those conditions. Now I know how much fluid to aim to replace per hour on the bike (which I was previously over-consuming), and I also know how many electrolytes to replace per hour (which I was substantially under-consuming):

Electrolyte Loss (mg/h)Loss (g/L)Normal Ranges
Na+6821.160.79 - 1.2 g/L
K+2070.210.20 - 0.27 g/L
Cl-9200.920.78 - 1.48 g/L

My heart rate response and core temperature response remained relatively stable throughout the test. This is a good sign because sweating is the body's cooling mechanism, and I am able to keep my core temperature under control, despite my low sweat rate.


In order to gather all of this data for the Sweat Rate & Electrolyte Test, at the end of my session, the team put me into a bucket with the towels that had been used to wipe my sweat throughout the test, and systematically rinsed me off in order to collect every droplet of sweat that I had excreted, into a "sweat soup," to be weighed and measured.

"Sweat Soup" Collection

After we took a lunch break, it was time for another soapless shower and the Sweat Rate & Electrolyte Run Test. The Kona conditions remained the same and I was thankful that this test was only an hour. Ryan even volunteer to run on the treadmill next to me for this last test but no one is allowed to enter the heat lab without a rectal thermometer, so he opted out. 

I lost another 1.3L/hour of fluid on the run, which is out of the ordinary since your core temperature is typically higher while running, and therefore your sweat rate is typically higher as well. However, I was losing electrolytes at a greater rate, and with my previous race plan, I was only replacing about 1/3 of what I was losing, contributing to my hyponatremia:

Electrolyte Loss (mg/h)Loss (g/L)Normal Ranges
Na+10300.930.79 - 1.2 g/L
K+3640.330.20 - 0.27 g/L
Cl-13841.250.78 - 1.48 g/L

Unlike the bike test, my heart rate and core temperature responses were indicative of someone who is not heat acclimated, and I sure felt as uncomfortable as these numbers look:  


Just imagine running with a 103 degree fever. That's kind of what it feels like to compete in Kona.... with a headwind. 

Because my next race will be Ironman Texas, in April, and I'll be coming from mild Colorado temperatures, it's going to be really important for me to become heat acclimated before racing. 

This blog post seems long enough for now so the next one will include strategies for heat acclimatization, race day fueling and hydration, and the results of my Sodium Balance Test (pee jug and diet log), and how that corresponds to daily hydration levels and daily electrolyte needs.

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