Dr. Singh explains that muscle tissue converts thyroid hormone T4 into its active form T3. Exercise preserves muscle mass and boosts T3 production. Stress and inflammation raise reverse T3, which blocks T3 and causes hypothyroid symptoms even when T4 and T3 levels look normal.
The conversion of T4 to T3 doesn't only happen in the liver. It also occurs in the kidneys and significantly in the muscles. This is a key reason why maintaining a good muscle mass and regular exercise are so beneficial for thyroid function, because they help convert the T4 into T3, which in turn improves your thyroid efficiency. And in addition, I would also like to add a very important player in the thyroid health dynamics, which is the role of reverse T3. So unlike T3, 3, reverse T3 does not support thyroid function. Instead, it blocks it. It competes with your T3 for receptors and can inhibit its action, leading to symptoms of low thyroid function even when T4 and T3 levels are normal. So this commonly happens during periods of stress or inflammation.
