Many of us notice that weight gain is all too common at midlife. We want to look for a reason...or an excuse. Often, a butterfly-shaped gland in the neck gets the blame: the thyroid. When it's underactive, a condition called hypothyroidism, your metabolism slows down. If the hypothyroidism continues to be untreated, you can experience a number of problems including dry skin, slow pulse, diminished reflexes and yes, weight gain.
But that's probably not the reason you seem to be putting on many extra pounds. Doctors say that a patient with hypothyroidism might gain as much as 10 pounds; more than that would be unusual. If you have gained more, the culprit is likely aging. Metabolism slows as you age, which means that you have to eat less and exercise more just to stay at the same weight.
Still, if you've noticed an unexplained weight gain, you should check with your doctor to see if something other than aging is involved. Hypothyroidsm is more likely as you get older with the peak coming between the ages of 35 and 60. It's diagnosed by a simple blood test, which measures levels of the thyroid hormones T4 and T3 as well as thyroid-stimulating hormone (TSH) in the pituitary gland. You need all three to make a diagnosis.
If you have hypothyroidism, your doctor will prescribe a medication to replace the missing hormone. You will need to be on it for the rest of your life.