The Thyroid Gland
The thyroid gland, located close to your adam's apple, secretes several hormones
which regulate metabolic rate, or the rate at which your cells burn energy.
Thyroid hormones also help regulate body temperature, sleep and digestive
functions.
Thyroid activity can go either too high or too low. Overactivity is known as
hyperthyroidism and is usually the result of auto-immune disease. (Auto-immune
disease is a form of imbalance in the immune system).
Typical symptoms include anxiety or restlessness, fatigue and weight loss.
Hypothyroidism, or under-activity of the thyroid, is much more common, especially
in women. In this case the symptoms can include fatigue and need for excessive
sleep, weight gain or inability to lose weight, constipation, susceptibiity to
feeling cold, depression and a foggy mind.
The thyroid itself is controlled by the brain, and in particular a region called
the hypothalamus. Both hyper- and hypothyroidism can result from inadequate
brain regulation of the thyroid.
Thyroid Controversy
Some doctors believe that low thyroid function is far more common than is
conventionally thought, and that the standard blood test used by GPs to diagnose
the problem is inadequate, in part because the norms are too broad.