Iodine is classified as a mineral, which of course is a component of T3 and T4. Other minerals such as copper, zinc, magnesium, iron and selenium are needed for proper glandular function and to help with thyroid hormone formation. For example iron for peoxidase formation, which helps with thyroid hormone formation. Selenium is also required form thyroid hormone formation and conversion of T4 in to T3.
Although if taken at the same time as thyroid medications the minerals calcium, magnesium and iron can interfere with the medication.
2. how is it related to lack of exercise?
Exercise can help by increasing circulation, reducing toxins, and most importantly helping to reduce stress, which adversely affects thyroid function.