Could your thyroid make you a bad driver?

Could your thyroid make you a bad driver?

Being under the influence of drugs or alcohol apparently isn’t the only thing that can impair your diving. A new study from theUniversity of Kentucky and the Veterans Affairs Medical Center in Lexington, KY suggests that people with significant hypothyroidism can experience impaired driving similar to those who are driving when intoxicated by alcohol.

Hypothyroidism is a condition in which the thyroid gland is underactive, according to the American Thyroid Association. Hypothyroidism means that the thyroid gland can’t make enough thyroid hormone to keep the body running normally.

“Hypothyroidism, insufficient thyroid hormone, is very common and has been known to cause impairment of many bodily functions, including brain function,” said lead investigator, Dr. Kenneth Ain, in a statement. “Until now, studies have not sufficiently explored the extent of brain impairment and whether hypothyroid people are safe drivers.”

In this study, thirty two patients with thyroid cancer, who were undergoing preparation for radioactive iodine scanning by stopping thyroid hormone, were evaluated with a battery of neurological and psychological tests, as well as testing on a driving simulator. They were studied when they were taking thyroid hormone, again when they were off of thyroid hormone, and then finally when they were back on thyroid hormone therapy.

Hypothyroid patients had depression and also showed declines in neurological function that resulted in increased automobile braking times; similar to the performance of drivers with a blood alcohol level of 0.082 g/100 mL. Taking thyroid hormone reversed all of these effects.

“Our results uncover a potential public and personal health hazard regarding impaired hypothyroid drivers,” Dr. Ain said.

Symptoms of hypothyroidism may be vague and can often mimic other conditions so be sure to talk with your doctor. Below are some of the most common symptoms:

  • Changes in the menstrual cycle
  • Constipation
  • Depression
  • Dry hair and hair loss
  • Dry skin
  • Fatigue
  • Greater sensitivity to cold
  • Slow heart rate
  • Swelling of the thyroid gland
  • Unexplained weight gain or difficulty losing weight
  • Carpal tunnel syndrome

Related Posts



  1. No comments by an Advocate endocrinologist—why???

  2. Hi Jay, do you have a question we can send to an Advocate endocrinologist? We are happy to help point you in the right direction.

  3. Why are the “new” guidelines, actually from 2002, followed per the AACE? It used to be .5-5.5 and now it is .3-3.0 for TSH? Advocate still uses the older guidelines. This is very frustrating for hypothyroid patients, especially Hashimoto’s patients.

  4. Don’t bother if you have Medicare- doesn’t even recognize it as a disease. Blame all on anything they can make $$$$$$$$$$$$$$$$$ off of. CORRUPT!!!!

About the Author

health enews Staff
health enews Staff

health enews staff is a group of experienced writers from our Advocate Aurora Health sites, which also includes freelance or intern writers.