Why does exercise wipe me out?: I am 2years post... - Thyroid UK

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Why does exercise wipe me out?


I am 2years post-thyrodectomy. Previously had hyperthyroidism caused by toxic nodules - although never suffered weight loss symptoms. Now on 125mg thyroxine (blood test results within normal range). Two problems remain 1) very slow metabolism - only pass stools 2x per week and 2) each time I push my exercise regime a little harder, I have complete wipe out where I literally sleep for a day. Any suggestions?

6 Replies

Sound like you're either under-medicated, or you have a conversion problem. But, without more information, impossible to say which.

What are you taking?

How much?

Do you have copies of your blood test results?

Have you ever had your FT3 tested?

Thanks. I’m taking 125mg of Levothyroxine - reduced from 150mg 3 months ago. Last blood tests by GP were in June 2018: serum T4 23.1 (0.1 above top of normal range) and serum TSH 0.22 (again just below 0.27 at bottom of normal range). No FT3 measure. Last Blue Horizon test in Feb 2018 showed FT3 as 3 just below normal range. All other results were normal

OK, so you have a conversion problem and your doctor knows nothing about thyroid. Reducing your levo would have reduced your FT3, and it's low T3 that causes problems. It's the FT3 that is the most important number but very few doctors know that.

So, that's why you are wiped out by exercise and have a low metabolism. If I were you, I would give up the exercise until you've raised your FT3 to optimal. Just gentle walking until then. And, what you need to do is add some T3 to your levo. But, I doubt your doctor would prescribe it. He doesn't sound as if he understands much about how these things work. So, you'd probably have to buy your own. Start a new post asking people to PM you their trusted links to buying T3 on-line.

Thank you for your advice. Really helpful. I suspected as much. I’ll start a new post to source the T3

You're welcome. :)


You also need to test vitamin D, folate, ferritin and B12

These often drop too low when we are poor converters

Add results and ranges if you have them

For full Thyroid evaluation you need TSH, FT4, FT3 and also very important to test vitamin D, folate, ferritin and B12

Private tests are available. Thousands on here forced to do this as NHS often refuses to test FT3 or antibodies


Medichecks Thyroid plus ultra vitamin or Blue Horizon Thyroid plus eleven are the most popular choice. DIY finger prick test or option to pay extra for private blood draw. Both companies often have money off offers.

All thyroid tests should ideally be done as early as possible in morning and fasting. When on Levothyroxine, take last dose 24 hours prior to test, and take next dose straight after test. This gives highest TSH, lowest FT4 and most consistent results. (Patient to patient tip, GP will be unaware)

Is this how you do your tests?

Did you feel better when Levothyroxine was at 150mcg?

If so request dose is increased back or ask for referral to endocrinologist of your choice for additional T3

Dr Toft, past president of the British Thyroid Association and leading endocrinologist, states in Pulse Magazine,

"The appropriate dose of levothyroxine is that which restores euthyroidism and serum TSH to the lower part of the reference range - 0.2-0.5mU/l.

In this case, free thyroxine is likely to be in the upper part of its reference range or even slightly elevated – 18-22pmol/l.

Most patients will feel well in that circumstance. But some need a higher dose of levothyroxine to suppress serum TSH and then the serum-free T4 concentration will be elevated at around 24-28pmol/l.

This 'exogenous subclinical hyperthyroidism' is not dangerous as long as serum T3 is unequivocally normal – that is, serum total around T3 1.7nmol/l (reference range 1.0-2.2nmol/l)."

You can obtain a copy of the articles from Thyroid UK email print it and highlight question 6 to show your doctor


Also request list of recommended thyroid specialists. Some will prescribe T3.

email Dionne at


Professor Toft recent article saying, T3 may be necessary for many. Note especially his comments on current inadequate treatment following thyroidectomy


A GP can no longer initiate T3 treatment, it must be diagnosed as clinical need by secondary care.

Personally I was determined NHS would acknowledge my clinical need. You can get T3 on NHS if you push hard enough

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