Best evidence I have is that I was diagnosed with an underactive thyroid about 13 years ago (my TSH was 314 when I gave the blood sample for the test). Over the next 8 years, I had my TSH checked every 6-8 weeks. After doing 50+ tests over time and keeping track of how I felt every day, my training level, racing performance, etc, I found that for myself, when my TSH was over 2, I was having problems in training and feeling far more tired outside of training than I ordinarily would, all things being equal. I also found that in general, I was training/racing the best when my TSH was in the 0.3-0.8 range. I don't have any links to provide you on articles, but I remember reading a few articles in 2001/2002 postulating that optimum TSH level varies in individuals. I am much too busy to look for the links at this point (and honestly, I don't care much because I don't run competitively anymore), but I'm sure a simple google search would reveal some good in-depth info.
noname wrote:
Californian wrote:The optimal TSH level varies for each individual. But I think doctors typically consider the range of 0.4 - 4.0 to be normal for the population as a whole. Which is a shame because some doctors fail to realize that you could have an underactive thyroid with a 2.5 TSH or an overactive one with a 0.8 TSH.
I'm not saying you are wrong. If you have scientific evidence that this is true, you would be giving alot of runners some great advice. But can you provide some research to back this up...and not a website with weight loss ads done by a "patient advocate".