Could a Thyroid Problem Be Causing Your Fatigue?

The thyroid, a butterfly-shaped gland in the neck, makes hormones that regulate the body’s metabolism, controlling how efficiently it converts nutrients and oxygen into energy.

Some of these hormones, particu­larly T3 and T4, affect how quickly the body burns calories at rest. When the thyroid produces optimal levels of these hormones, body temperature and heart rate increase, and the nervous system activates to produce quicker reflexes and greater alertness. But when the thyroid grows sluggish, so do we.

An underactive thyroid — a condition known as hypothyroidism — can leave you “feeling like you’re carrying around bags of cement,” says Haas. You might also feel cold, dry, constipated, and foggy.

“Thyroid [production] has to be very low for prolonged periods of time for a lot of these symptoms to appear,” notes ­functional-medicine physician Gregory Plotnikoff, MD, MTS, FACP. This means that low-grade thyroid problems may be sapping stamina well before the classic signs emerge.

How to Address:

A basic clinical ­approach often includes testing for thyroid-stimulating hormone (TSH), but it can be worth going deeper with a full thyroid panel, says Haas. “There’s a pretty broad range in which TSH is considered to be normal, but it can still be suboptimal.”

Even if TSH is normal, suboptimal levels of T3 and T4 can cause symptoms.

If testing indicates a sluggish thyroid, a combination of treatment and lifestyle adjustments can help get things back on track: targeted thyroid medication when appropriate plus steady, protein-anchored meals; stress and sleep support; and follow-up labs to make sure the complete thyroid picture (not just TSH) is improving.

“These are easy things to test and relatively easy to correct when they’re out of whack,” Haas says.