Hypothyroidism

If you have hypothyroidism (underactive thyroid), your thyroid gland is not producing enough of the various hormones that keep your body in good working order. Low thyroid slows your metabolism, so you're likely to feel tired, gain weight and feel unusually sensitive to cold. Being a woman over 60, having an autoimmune disease and being pregnant are some factors that can put you at risk.

Low thyroid symptoms can vary. For some people, they come on very gradually -- in others, they appear more suddenly, over a few weeks or months. In general, symptoms will get worse as your thyroid levels get lower. The best way to find out if your thyroid is low? Ask your doctor for a thyroid test, also called a TSH test. In some cases, your doctor may also want to test your thyroxine level. 

Hypothyroidism is most common in people over 50 and women past menopause. If you've already been diagnosed with hypothyroidism, be aware that symptoms can get worse with age, so you might need to adjust your medications accordingly.