"Foot power" is the standard mode of transport for a lot of Manhattan workers. But attorney Diane Wolf grew so tired that walking to the end of a block "felt like climbing Mount Everest and back."
Wolf, in her 50s, was also badly constipated, deeply depressed, and had gained 20 pounds. She tried to work out, but she could barely pedal past the "0" mile mark on her stationary bike. Baggy eyes, brittle nails, and thinning hair rounded out her symptoms. "I was a mess," she says.
Like millions of other Americans—most of them women—Wolf was enduring the effects of a faulty thyroid gland.
The thyroid makes thyroid hormone, which governs heart rate, metabolism, and other organ functions. When your thyroid is underactive, called hypothyroidism, the more common glitch, you may slow down. You're tired. Depressed. Fuzzy in your thoughts. Constipated. You gain weight. Your skin dries out. You feel cold when it's warm. You may have heavy periods.
On the flip side, if you have an overactive thyroid, called hyperthyroidism, you're apt to lose weight, sweat more, and have trouble sleeping. Your heart rate rises. You may feel jittery.
What causes thyroid disorders, and why do they strike women five to eight times more often than men? The answers aren't clear.
"We know there is a family history link and very likely a tie to autoimmune disorders like lupus," says Rhoda H. Cobin, M.D., an endocrinologist in New York City. Thyroid deficiencies also rise with age. After age 60, about one in five women has low thyroid hormone.
The symptoms are not specific and can mark a lot of other disorders. That makes a thyroid problem easy to miss.
"Roughly half of the people with thyroid conditions may be undiagnosed and continue to struggle with symptoms," says Dr. Cobin. As Diane Wolf put it, "I saw specialists to get at the bottom of my depression, constipation, and chronic fatigue, but nothing worked."
That is, not until a doctor ordered a blood test to check Wolf's thyroid stimulating hormone (TSH), which controls production of thyroid hormone. When TSH is high, it means production of thyroid hormone is slowing. When TSH is low, thyroid hormone production is in overdrive.
Wolf's TSH was high, meaning her thyroid was underactive. Thyroxine, a thyroid replacement pill, helped normalize her thyroid, restore her energy, melt the weight, and end other symptoms. "Even my hair became shiny again," she says.
But that doesn't mean everyone with these symptoms should start popping thyroid pills, warns Lawrence Wood, M.D., from the Thyroid Foundation of America. "Too little thyroid hormone can set you up for infertility and heart disease, but too much thyroid when you don't need it can hurt your heart and your bones," he says.
"As baffling as weight gain, fatigue, and other symptoms may be, there's no justification for treating with a thyroid hormone if you have no measurable deficiency," adds Dr. Cobin.
Doctors don't agree what a measurable deficiency is. Dr. Cobin suggests you discuss treatment with your doctor if your TSH is above the "normal" levels of 4 or 5. Your doctor may suggest a repeat test, a trial of medication, or both to see if your symptoms start to clear up.
What if the results are borderline but you still have symptoms? Ask your doctor to repeat the test later. That may show if a possible thyroid deficiency is worsening, Dr. Cobin says.
Who should be tested? Women who are pregnant or planning a pregnancy top the list. One in 50 U.S. pregnant women is diagnosed with underactive thyroid. "Even a mild thyroid deficiency can affect the baby's developing brain," says Helena Rodbard, M.D., a past president of the American Association of Clinical Endocrinologists.
After pregnancy, some women come down with a thyroid deficiency when the immune system goes into hyperdrive and suppresses production of the thyroid hormone. "Women should be monitored before, during, and for six months after pregnancy," Dr. Rodbard says.
If you're a woman older than 50, ask your doctor about a TSH test. It's also wise to seek a test if you have:
A family history of a thyroid disorder, abnormal cholesterol, or an autoimmune disease, such as lupus, diabetes, or rheumatoid arthritis.
A set of underactive thyroid symptoms that includes cold intolerance, fatigue, forgetfulness, heavy periods, dry hair, mood swings, weight gain, a hoarse voice, dry skin, constipation, thinning hair, and loss of the outer third of your eyebrows.
A set of overactive thyroid symptoms that includes heat intolerance, sweating, weight loss, changes in appetite, frequent bowel movements, changes in vision, impaired fertility, anxiousness and sleep problems.