For people with significant hyperthyroidism, commonly caused by the autoimmune disorder Graves' disease, exercise can overheat the body in a dangerous way.

What is the best exercise for hyperthyroidism?

This doesn't mean you should avoid exercise if you have hyperthyroidism — on the contrary, it may be helpful to start off with lower intensity exercises. Walking, yoga, and tai chi fall into these categories. It might be worth seeking out a personal trainer with experience helping hyperthyroid clients.

What can worsen hyperthyroidism?

Iodine-rich foods

Too much iodine can make hyperthyroidism worse by leading the thyroid gland to produce too much thyroid hormone. A person with hyperthyroidism should avoid eating excessive amounts of iodine-rich foods, such as: iodized salt. fish and shellfish.