Medical Specialty >> Endocrinology

Doctors Lounge - Endocrinology Answers

Back to Endocrinology Answers List

If you think you may have a medical emergency, call your doctor or 911 immediately. Doctors Lounge ( does not recommend or endorse any specific tests, physicians, products, procedures, opinions, or other information that may be mentioned on the Site.

DISCLAIMER: The information provided on is designed to support, not replace, the relationship that exists between a patient/site visitor and his/her physician. Please read our 'Terms and Conditions of Use' carefully before using this site.

Date of last update: 10/17/2017.

Forum Name: Endocrinology Topics

Question: Training for distance running...Thyroid trouble

 running - Sat Feb 14, 2009 7:17 pm


Thank you for your help. I am a 41yo woman with an excellent health history. I started running athletically last year, I am training for a marathon. I work in health care. Recently I ran a long course and afterward experienced symptoms similar to those I had when diagnosed with a goiter and hyperthyroid problems at the beginning of my last pregnancy: increased heart rate, fatigue, headache, light sensitivity, anxiety. I ran my own labs: TSH = 0.384, Free T4 = 1.17, Free T3 = 3.0, and Antithyroglobulin antibody = 131. My non-fasting triglycerides are at 44.

My symptoms were bad for about ten days, then improved and I have been feeling mostly better the past week, but not great. I went for another long run today and felt O.K. but did not have nearly my normal level of energy. I wear a heart rate monitor to track my running statistics and was surprised to find when I got home that my heart rate for the last third of my run jumped suddenly to consistently over 200 (max 240) compared to my normal 140 or so. Again, I feel O.K. but not great and my heart rate is still a little high several hours later (85 vs. my normal 60-65).

I realize my labs are somewhat subclinical. I want to keep training. I am a breastfeeding mom.

Would you advise me to seek treatment? Is it likely that I would be started on PTU? Should I just wait and repeat my TSH if my symptoms worsen? Will I cause muscle damage, or moreover, is it likely that I am endangering my health to continue training? I have been trying L-Carnitine and have been thinking that it perhaps helps somewhat with the headache. After my run today I am wondering whether I should be more concerned about my heart. I'm at a point in my life when
I really don't want to have to slow down and stop running if I can avoid it. Please let me know your thoughts. I sincerely appreciate it!
 John Kenyon, CNA - Mon Feb 23, 2009 9:36 pm

User avatar HI there -

Everything you describe regarding your body's response to vigorous exercise corresponds with your original diagnosis of hyperthyroidism with goiter, yet your labs (which should be repeated completely independently) are not only subclinical but within normal limits near as I can tell (given that T-4 range will probably soon be lowered to .3 - 3.0). You may have triggered a response by your running program (remember, thyroid disease is not a fixed entity and can be variable, which is why you need to have levels checked periodically). Since your levels will likely be similar to what they were (about normal) when retested, you may not be put on PTU. However, you need to have the cardiac response to exercise evaluated anyway, independent of the thyroid issues. While what you report is commonly seen in hyperthyroidism, and your own labs don't reflect a parallel with the symptoms, you do have something going on. With your history the first suspect has to be hyperthyroidism. You also may have learned, due to your original bout with hyperthyroid state, some faulty breathing patterns which have been found, in studies, to affect runners and other athletes with this problem. There isn't increased airway reactivity, but the respiratory muscles are weaker and for some reason the compensatory breathing pattern becomes faulty (rapid and shallow).

You should probably have a formal thyroid workup as well as LFT and at least a resting 12-lead EKG. Correlate these findings to determine what may be going on. It could still be thyroid-related, or it may be some sort of secondary heart problem (not structural, but perhaps due to residual sympathetic imbalance) (Kendrick, O'Reilly and Laszlo).

You won't likely cause muscle damage, at least not of any lasting sort, but you could precipitate thyroid storm by working out at your existing pace, even though your labs appear, at worst, subclinical and at best, normal, right now. There's also the risk of developing A-fib, as you know.

I just don't think self-management is the best route. We in the business tend toward this sort of approach quite often, and there's an old maxim that covers this: "A doctor who treats himself has a fool for a patient." Doesn't have to be a doctor to fit the category, but we can really make some bad calls when we're at the center of our own process. For this reason I hope you'll have the affected systems evaluated and come up with both a diagnosis and program that will fit your situation. If you do wind up hyperthyroid (and it does seem likely), there are ways of accomodating a pretty solid fitness regimen. Certain things simply have to be recognized first.

Hope this is helpful. Best of luck to you. Please follow up with us as needed.

| Check a doctor's response to similar questions

Are you a Doctor, Pharmacist, PA or a Nurse?

Join the Doctors Lounge online medical community

  • Editorial activities: Publish, peer review, edit online articles.

  • Ask a Doctor Teams: Respond to patient questions and discuss challenging presentations with other members.

Doctors Lounge Membership Application

Tools & Services: Follow DoctorsLounge on Twitter Follow us on Twitter | RSS News | Newsletter | Contact us