Baxter Bell's reply:
It's easy to say that yoga can cure just about any malady, given the media's tendency to metamorphose yoga's potential benefits into "cures." Yet, to the best of my knowledge, hatha yoga cannot cure hyperthyroidism (HT), a condition in which the thyroid—the small bow-tie-shaped gland in the throat—is overactive.
Western medicine has effective treatments that can help this condition, but they can sometimes leave you with an underactive thyroid gland. It can therefore be beneficial to seek out options for treatment other than Western pharmaceuticals and surgery. One good friend of mine with Grave's disease (the most common of the more than 10 different variations of hyperthyroidism) was able to bring her thyroid hormone levels down to normal using traditional Chinese herbs and acupuncture.
Because HT has potential life-threatening complications, it's best to begin with Western or effective complementary medicine therapy. Then you can add a hatha yoga practice to support those therapies. HT can have dangerous heart-related effects, such as a sustained elevation of heart rate, congestive heart failure, and, most worrisome, a rapid and irregular heart rhythm. Other complications can include shortness of breath (both at rest and when active), bone loss (which can lead to osteoporosis), hyperactivity, anxiety, insomnia, muscle weakness, excessive sweating, and abnormal weight loss despite an increase in appetite.
If your hyperthyroidism is in its early stages, tailor your yoga to quiet your body and mind. An aggressive practice could worsen the heart-related complications, so try focusing on restorative postures and continue to do so even after the illness has gone on for a while, since your body can become depleted of energy (as evidenced by continued weight loss).
According to yoga tradition, Sarvangasana (Shoulderstand) has a powerful effect on the thyroid. Although there are no Western studies to support this assertion, Sarvangasana can be safely included in your repertoire of asanas as long as your cardiac status is stable and you don’t have high blood pressure. You might also consider modifying it using a chair to make it more restorative; ask your yoga teacher how to do this.
Baxter Bell, M.D., teaches public, corporate, and specialty back-care yoga classes in Northern California, and lectures to health care professionals around the country. A graduate of the Piedmont Yoga Studio's Advanced Studies Program, he integrates the therapeutic applications of yoga with Western medicine.