Hypothyroidism occurs when your thyroid gland doesn't make enough thyroid hormones. The thyroid is a small, butterfly-shaped gland located in the front of your neck. It produces hormones that regulate the body's metabolic rate by constantly releasing thyroid hormones into the bloodstream.

If you have hypothyroidism, your metabolism slows down and you burn less energy, which can lead to weight gain. Also, many people with this condition feel tired, which may prevent them from exercising.

The body's control of the thyroid levels helps stabilize mood. Patients with hypothyroidism may experience symptoms of depression, restlessness and anxiety. Studies have also found that people with bipolar disorder often have abnormal thyroid function.

Hypothyroidism slows down your metabolism. Research shows that eating a higher protein diet can help increase the rate of your metabolism.

Exercise can be dangerous for people with uncontrolled hypothyroidism. Because your metabolism and heart rate are slower, certain types of exercise can be hard on the heart. Always talk to your physician before beginning a fitness routine.