Effect of exercise on thyroid blood tests? - Thyroid UK

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Effect of exercise on thyroid blood tests?

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Just wondering,what effect have people noticed on their blood tests if exercising the day before/same day/other time?

SlowDragon has previously shared that the ideal time for thyroid blood tests is just before 9am, and I'm wondering if exercising should also be taken into account?

pubmed.ncbi.nlm.nih.gov/163... "Results: The results of this study show that exercise performed at the anaerobic threshold (70% of maximum heart rate, lactate level 4.59 +/- 1.75 mmol/l) caused the most prominent changes in the amount of any hormone values. While the rate of T4, fT4, and TSH continued to rise at 90% of maximum heart rate, the rate of T3 and fT3 started to fall.

Conclusions: Maximal aerobic exercise greatly affects the level of circulating thyroid hormones."

Interested and appreciative of people sharing different experiences.

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10 Replies

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2 years ago

Couldn't tell you about bloods but running a half marathon was what pushed me over into hypothyroidism. My body totally gave out and I had a mini breakdown.

• in reply to2 years ago

Hi Wichinghour, thank you for your reply. I hope you are okay now?

Your experience confirms what I have suspected. How long did it take for you to recover after your half marathon?

• in reply to2 years ago

I ran the halfer in Sept 2019 and got my diagnosis in June 2020. Hypo symptoms have been lifelong; defo since my teens anyway! So while it was horrendous at the time I think without doing the halfer is still be bumbling along 'not-quite-right' so I'm glad I did it.

I don't think I ever actually recovered from that race; I've not run a single step since because my health just won't let me.

I'm better that I have been in years and years but I just don't have the reserves for running anymore.

• in reply to2 years ago

Good point of view about finding out...although it has cost you. x

Buddy195Administrator2 years ago

In order to get sufficient blood for a finger prick test, I do exercise prior to an early morning blood draw but haven’t noticed any changes to my test results. I have found that a slightly higher dose of T3 (I’m on combination treatment) has helped me reduce previous fatigue from exercise.

radd2 years ago

Wunderkid,

But those results are taken from people with a functioning thyroid gland who have a normalised response to thyroid hormone converting enzymes and good adrenal reserve.

The adrenals respond to any stress including exercise and I read somewhere that in a healthy person, cortisol kicks in after about 40 minutes of intense training but in compromised adrenals it is much quicker and will be adrenaline if cortisol is in low supply.

Also many of us have a reduced variation of T3 levels being totally reliant upon our meds, as have no thyroid gland, have lost TSH's converting help, and risk the common genetic conversion impairments (DIO1 & 2 mutations).

Exercise should promote well being (eg sensitise cell receptors, improve hormone uptake, etc ) and T3 is known to best promote more protein synthesis and muscle growth but unless you have found a good level of well being on thyroid replacement meds, it is difficult to compare apples with pears.

• in reply toradd2 years ago

Wondering what your direct experience is when you exercise and then have blood tests?

2 years ago

Hi Buddy195.

Good tip about exercising for blood circulation for finger prick test.

The only experience I've had in a similar area, was to use warmth to make a heel prick test easier (in a baby).

Like your tip re T3 and fatigue, thanks. 👍 (Will keep it for future reference if I need it.)

And your experience of needing T3 to combat fatigue, seems to confirm the results of the study.

tattybogle2 years ago

healthunlocked.com/thyroidu... the-effect-of-acute-exercise-session-on-thyroid-hormone-economy-in-rats

healthunlocked.com/thyroidu.... after-a-run-ft4-ft3-go-up-from-your-normal.-but-12-hours-later-ft4-ft3-will-have-gone-down-below-your-normal-.cortisol-affected-too.

• in reply totattybogle2 years ago

Thank you for the links, tattybogle. 👍