When Carmichael Training Systems (CTS) Coach Jason Koop and I looked into building a training program for Dean Karnazes's attempt to run the Endurance 50 last fall (50 marathons in 50 days in 50 States), we scoured reams of medical studies to see if anyone had charted the physiological demands of doing any activity for 50 straight days. We found nada. And after looking into this gaping vacuum of science, I decided there was only one thing to do: add to our endurance performance expertise by making a case study out of Karnazes's runs. Throughout his seven-week blitzkrieg, we'd take blood and urine samples from him, analyzed them, and use the results to tweak Karnazes's day-to-day runs.



We took samples every three days to measure, among other things, creatinine phosphokinase (CPK)-an enzyme found in muscles that pours into the bloodstream if there's any muscle damage, which materializes as soreness. The greater the damage, the more CPK ends up in the blood. The revelations started streaming by his 8th marathon in Boulder, Colorado. Bryan Bergman, a CTS coach with a Ph.D. in exercise physiology, reviewed the data and noticed that Karnazes's CPK only started to slowly increase after a week of marathons. By marathon 25 in Baton Rouge, Louisiana, the CPK count had increased again, but not by much.



"What impresses me about Dean is his low level of CPK (447units/liter) after completing 25 marathons without a rest day," says Bergman. "A 'normal' response for a moderately-trained runner completing one marathon is a CPK jump from 163u/l at the start to over 2,400u/l a day after the race. Two days later it's still over 1,800u/l. Dean's number stabilized at 450 and even started dropping."



In other words, over the course of 50 marathons, his body had adapted to his running schedule to the point that pounding out 183.4 miles a week caused no more muscle damage than walking the halls at an office job.



In addition, we tracked Karnazes's hemoglobin and hematocrit numbers to tell us if he was malnourished or dehydrated. His first blood draw showed us that he suffered from mild athletic anemia: his red-blood-cell count was low enough that a non-athlete would have been advised to start taking iron supplements. But Karnazes's numbers were the result of endurance training; his plasma volume, the non-red blood cell component to blood, was greater than most peoples'. And what initially seemed like a concern was actually a benefit. This plasma volume meant there was more total fluid in his bloodstream which allowed him to resist dehydration and optimize his body's ability to cool itself by shunting a higher volume of blood-and heat-towards the skin's surface.



Even so, both Bergman and Koop, who was on the road with Karnazes, had to stay on top of his food and fluids. After Karnazes knocked off the most grueling travel section of the E50, with fluid-sapping, round-trip flights to Anchorage, Alaska and Maui, Hawaii, he started showing signs of dehydration in his hematorcrit and hemoglobin concentration levels even though he was chugging roughly a 1 3/4 gallons of liquids a day.



"Worse than the travel was the climate extremes Dean experienced on the western swing," says Koop. "He went from the cool of Portland, Oregon to the cold of Anchorage to the humidity of Maui then on to the blazing heat of Arizona over five days. That really threw his assumed hydration needs out of whack. Considering how vigilant both Dean and I were about keeping him hydrated throughout that experience, it was an eye-opener to learn that we should've had Dean drink even more."



By October 24th, Day 37, Karnazes's samples showed that Koop had brought Karnazes back to a fully-hydrated state and his CPK number showed a runner in prime working order. He'd stay that way through the end, clocking a 3:00:30 marathon in New York City.



So, what did we learn from Karnazes? It confirmed the value of high-volume training for endurance athletes. I'm not talking about volume in terms of months, or even years, but decades. Karnazes's ultramarathon habit has, over the last 13 years, built up his bone-density, joints, and running muscles and blood transport system to the point where he can motor along forever at a 7:00- to 10:00-mile pace is only limited by his supply of food and fluids not muscle damage or joint pain.



Chris Carmichael is founder of Carmichael Training Systems and author of 5 Essentials for a Winning Life (Rodale).

This content is created and maintained by a third party, and imported onto this page to help users provide their email addresses. You may be able to find more information about this and similar content at piano.io