Ellis? - Isn't this a hyperthyroidism question above? - I was just making sure.
If I am reading it right you posted "hyperthyroidism" which can change up the answer on your question.
Would it be possible to post your labs to see where you are at? - and also know if this is autoimmune related.
Many factors with cardio if hyper can contribute to this suggestion. At least for me - I'd like to make double sure before I post.
The short answer, as it always is, talk to your Doc before starting exercising or playing sports.
But here are some sites that might help you: http://www.thyroid-info.com/articles/exercise.htm... and....http://www.gffi-fitness.org/Art_10.htm They are both sites dedicated to hypothyroid an exercise and/or lifting weights.
Hope this helps.
Ellis