I was diagnosed as being hypothyroid a couple of years ago. I was in my 40's with a family history of hypothyroidism, so not a huge shock. However, I had been training hard with a coach for a couple of years, looking to improve my local yokel status, and now I wonder if it may have tipped the balance for me. Once I became hypo, I started to notice how many young talented runners, not your usual demographic, were hypothyroid. I know there have been studies pointing to long distance training suppressing the immune system, could there be something analagous for the thyroid with intense training? Especially if one is prone to thyroid issues anyway?