Friday, August 27, 2010
The Long Road to Nutrition Self-discovery
In rethinking "the whole race," I have to start by analyzing exactly what went wrong nutritionally during the run at Ironman Lake Placid five weeks ago. All my fueling up UNTIL the run seemed to be working great. Even up until the SECOND HALF of the run. There were no obvious warning signs -- no extreme fatigue, thirst, or lightheadedness -- until it was too late. Even the vomiting I did around mile 15 did not give me the sense there was a larger problem. But in analyzing the data, I've narrowed it down to two causes: hyponatremia and an overly-aggressive run pace. They were probably co-conspirators in my take-down.
I didn't just pull these two things out of thin air. I read. A LOT. I thought about my nutrition issues. A LOT. And I had help. My friend Jo-Lynn is a nurse and an honorary member of the J-Team. She took the scientific approach and explained what was going on with my stomach when it "shut down." I also have a friend who told me where to take a second look -- at my "run splits." After a 100-mile ride in 90-degree temperatures, Julie (J3) is convinced it was "the heat." I took all these things into consideration, looked back at my training and racing nutrition in the recent past and started to draw conclusions.
Starting with when things began to look "not quite right" in Lake Placid -- I guess it was that mile 15 or 16 of the marathon. I think I misdiagnosed my first bout of nausea and vomiting as caused by eating/drinking too much (a.k.a. the dreaded "sloshy stomach"). It was more likely the beginning of my stomach shutting down. Vomiting appeared to solve the problem because I already had enough hydration in me to last several more miles. But everything I drank after that never got into my system. Thus, when I had my seemingly unending "vomit-fest" at mile 20 and when I was diagnosed with "dehydration," the underlying cause was probably hyponatremia. I didn't just need more fluid, I needed more salt to help me absorb the fluid and balance the electrolytes in my system.
I've been aware of this thing called hyponatremia since 2008 when I was training for the Philadelphia Marathon. During that time, I would vomit during most of my runs over 2.5 hours, and I usually vomited at the top of the last hill (after fatiguing my legs the most). I was baffled. I never had this problem when I trained for marathons in the 1990s (in my 30s). I did some reading, learned about the condition, added electrolytes to my training runs and the problem went away. I concluded my body chemistry had changed over time, and I was sweating out more salt now that I was "old."
Of course, the hotter the weather, the more we sweat, the more we need to replace fluids, and therefore the more salt I need. Not everyone will have this problem. Jo-Lynn wrote in her assessment: "All people's body chemistries are different and Ph's slightly different, sweat rate, and sweat composition." It's not my sweat rate I'm worried about, it's the saltiness of my sweat. How do you measure that? You can measure how much fluid you lose in a run by weighing yourself before and after, but how does one determine how much salt is needed? Is it just trial and error? Is there some kind of salt litmus paper?
The kicker came in a half-iron triathlon race I did last weekend. I got off the bike in relatively cool temperatures and then the sun came out and turned the heat index up to about 84 degrees F. I had forgotten my Hammer Endurolytes, so I replaced them with the brand "Salt Stick" which we were told had five times the amount of sodium. I took one near the beginning of the run, but about half way through, I started to feel nauseous again. I slowed my pace, drank only sports drink and took an Endurolyte at an aid station -- that pretty much cleared up the problem.
So, then, why do I also think an overly aggressive run pace added to my problem in Lake Placid? Because in looking at my splits, I was out way faster than I had planned. I was attributing it to the downhills, but near the beginning of the second loop, I did start feeling a little pain in my quads that might suggest I was running too fast. This also messes with your fluid absorption rate -- blood is shunted away from your stomach for use in other muscles. I think it was a contributing factor in the early part of the marathon.