Saturday, April 21, 2012

Running to endocrine exhaustion

Last year I went for VO2max testing and learned that my body was burning protein for energy and was in a state of catabolism. Nutritional blood markers suggested that I was not eating enough calories and that my muscles were glycogen depleted. Follow up blood testing showed that my endocrine system was out of whack with very low levels of vitamin D, IGF-1 and testosterone. Since that time, I have been struggling to get my body back into balance and find new ways to train to avoid ending up back in the same place. Several repeated blood tests over the course of 2011 showed no real change in nutritional markers or hormone levels despite increasing my calorie intake to first 3,000 and then 4,000 calories a day (easy to track with myfitnesspal). I quickly put on twenty pounds, but my body was still in a catabolic state. After my running season ended in October with a glorious day in the Grand Canyon, I decided to limit the length of time running on any given day to two hours or less for a couple of months to see if this would help. Finally, when the blood test results came back in January, almost a year after the first tests, the nutritional markers and most of the hormone levels were back to normal.

Prior to getting my test results and doing some research on the connection between endurance exercise and endocrine system, I wasn't really aware that there was a connection. I had heard of the female athlete triad (you can read about Anna Frosty's experience here), but I wasn't aware of the more general connection between exercise and hormones in athletes of both sexes. I have been reluctant to write about this experience on the blog since it is impossible to analyze my experience and understand what caused the problem in the first place or understand which if any of the various changes I made in nutrition and exercise habits that hopefully has fixed it. However, it did seem possible that endurance exercise or excess amounts thereof was at the root of the problem and if that is the case it seems likely that other ultrarunners may experience similar problems so I thought it might be helpful to link to some of the information I found on this subject.

There are publications in the scientific literature documenting a connection between endurance exercise and hormone imbalances although I couldn't find anything very useful in terms of how frequently this happens or how much exercise might cause it. Some exercise and fitness web sites advocate weight training to improve anabolic hormone production and avoid the "negative catabolic (breakdown) effect of hard endurance training". Ben Greenfield says that "hormonal deficits are the biggest problem among endurance athletes" and he advocates weight training and increased fat consumption to stimulate anabolic hormone production while replacing or minimizing long endurance training sessions with shorter higher intensity workouts to minimize the negative effects of endurance training. Lucho has posted a nice article from UltraRunning Magazine on his blog that describes the importance of the endocrine system for endurance athletes, although it doesn't address any of the specific imbalances that appeared in my tests.

I have made a variety of changes in order to try to fix the endocrine problems. In addition to increasing calories, I began taking vitamin D and magnesium supplements. I added weight lifting and sprint sessions to my workout schedule last year. Now that I have completed the Coyote Two Moon 100 miler, I currently don't have any races on my calendar for 2012 and am starting to experiment further with my training. I have continued the weight training sessions and am again limiting weekly long runs to two hours. I am running with a heart rate monitor for the first time in years see if that will improve the quality of the running sessions. The good news so far is that after two years of mostly running on tired and sore legs, I now have a lot of days where my legs really have a lot of energy. The jury is still out on whether or how that translates into performance at an ultra.

Any other endurance athletes out there with similar experiences?


  1. Wow. Did you wind up going on thyroid medication? I have had to adjust my thyroid medication dosage a few times. I have been on thyroid meds for about 20 years and it has only been in the past few years that I have had to increase the dosage, most likely from endurance training. I also have had to increase my vitamin D and that is still a work in progress. It does seem like the new trend is higher intensity training vs long slower-paced training. I find it makes a difference and perhaps help keep the body balanced both physically and mentally. Did you consult a nutrionist at all about eating for endurance training/racing? If you are interested in talking to a nutritionist, I know of a really great one who is herslef an endurance athlete. Are you planning on doing an other races this year?

  2. @Allison No, the doctor was concerned about thyroid, but the various tests for thyroid function have been within normal ranges so far. The doctor did refer me to a nutritionist and I went although I did not work with the nutritionist very much. I am not signed up for any races at the moment and am planning to do more adventure runs than races this summer but we'll see.

  3. Hi,
    I have a quick question about your blog, do you think you could email me?