Courtesy of Charlotte Brynn, Brynn Swim, Vermont.

Dr. Peter Attia explained the physiological effects of swimming across the Catalina Channel in 2005. A swim that took him 10 hours 34 minutes through an October night [shown above] he described as ‘Swimming in the ICU.’

To study the physiologic impact of marathon swimming I decided to use myself as a guinea pig on during my Catalina swim in 2005.

My friend, Marc Lewis, who is also a doctor, drew my blood for a complete panel of labs 3 hours before I started my swim, and immediately after I finished. Some of the lab results were ‘expected’, such as my sodium level going from a low-normal (142 mEq/L) to a high-normal (148 mEq/L), as a result of ingesting quite a bit of salt-water. Some blood tests that measure dehydration – coupled with an immediate pre- and post-swim body weight – suggested I was neither dehydrated or super-hydrated. However, the lab results that surprised me the most were the counts of my blood cells.

My CBC (complete blood count) was completely normal before the swim.

Immediately after, however, it showed changes compatible with a condition called SIRS, systemic inflammatory response syndrome. Without getting into the details of SIRS, my white blood cell count and platelet count had risen from normal by 5- and 3-fold, respectively. These blood results are typically seen in patients with profound infections or traumatic injuries, as a result of an inflammatory cascade in the body leading to margination of blood cells (e.g., certain types of white blood cells, platelets) and leaking capillaries.

Several months later, we repeated the experiment when Marc swam the Catalina Channel. The results were the similar.

While a sample size of two is hardly worth drawing conclusions from, I am convinced that marathon swimming is stressful enough to induce an ‘inflammatory cascade’ in the body. When the body is under extreme physical stress (e.g., infection, tissue damage), immune cells in the bloodstream are activated and release chemicals (cytokines), which dilate capillaries (leading to capillary leak), and inciting an inflammatory response throughout the body.

– swimming for 10+ hours is as stressful to the body as having the worst infection, or being hit by a car. It is actually like being in the ICU.

Well, I found this very helpful, my blood work was consistent to someone having been hit by a car, add in my water toxicity and we have ME post swim. I continue my research, reading articles on Hyponatremia and electrolytes, helpful reading on recommended electrolyte intake during exercise confirming that my feed mixes were within recommended intakes and mixed correctly, excellent, but how did my body get so out of balance?

For more information and the rest of Dr. Attia’s post-crossing analyses, read Charlotte Brynn‘s blog here.

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