Exercise reduces T3, Vitamin C lowers high cortisol, Interesting theory about iodine…and more.

POTBELLY PIGDESICCATED THYROID QUOTE OF THE DAY:I had potbelly pigs as pets for 18 years (my kids were allergic to cats and dogs). I took darn good care of them! Now pigs are taking care of me! :c)”  ~Thyroid Patient Tula


Look for a future announcement! It will only be available via the publishing company at first, which is here: http://www.laughinggrapepublishing.com


There has been some hoopla around the net about the possibility of endurance training affecting thyroid function in a negative way, especially in women (but could happen to men). And when women stop their endurance or cardio training, they see their T3 levels come back up where they should be. One article cites 80 difference references about problems caused from excess training or exercise. But what I fail to see mentioned in many articles is the potential physiological reason why. First, more intensive exercise raises cortisol levels (in those with healthy adrenal function–not in those with sluggish adrenal function). Both higher levels of cortisol, as well as increased inflammation, inhibit the conversion of T4 to T3. This inhibition raises the levels of Reverse T3, which lowers the cellular receipt of T3. And here’s something quite interesting also found in this article:

“….low intensity exercise (40%) does not result in significant increases in cortisol levels, but, once corrections for plasma volume reduction occurred and circadian factors were examined, low intensity exercise actually resulted in a reduction in circulating cortisol levels.”

The above biological fact about exercise and cortisol is another reason why intense exercise becomes a no-no if saliva testing proves you already have an adrenal (sluggishness) or HPA feedback issue.


I thought I knew a lot about Vitamin C until thyroid Patient Kristian told me about Vitamin C helping to lower high cortisol. Well Blimey and Blow me down!! This article reveals, via certain studies, that taking 1,000 mg of vitamin C before a workout lowered high cortisol even 2 and 24 hours after the workout, or taking 1500 mg Vitamin C for eight days put cortisol 57% lower….and more. So perhaps we have another treatment for thyroid patients who find themselves with high cortisol (as revealed by a saliva test, NOT a blood test) or a mix of highs and lows. This Psychology Today article says Vitamin C might be an essential part of stress reduction, which a mix of highs and lows in which saliva testing reveals.


From 2004, the article titled “Nutrition, evolution and thyroid hormone levels – a link to iodine deficiency disorders?” proposes that iodine deficiency may be more about historical changes in what humans now eat rather than a decrease of iodine from the environment. He explains that T3 is actually dependent on the amount of carbs we eat. He states:

While our Paleolithic ancestors subsisted on a very low carbohydrate/high protein diet, the agricultural revolution about 10,000 years ago brought about a significant increase in dietary carbohydrate. These nutritional changes have increased T3 levels significantly. Higher T3 levels are associated with an enhanced T3 production and an increased iodine requirement. The higher iodine requirement exceeds the availability of iodine from environmental sources in many regions of the world, resulting in the development of IDD.


Normally, inflammation is a naturally healthy and positive response of your immune system to counter the infectious problem of a virus, bacteria or fungal excess. It can also be activated by an irritant (picture a splinter in your finger) or damage to your cells from an injury.

But in thyroid patients, especially those who have remained undiagnosed or poorly treated on T4-only meds, the inflammation response can become chronic and problematic! You might even get the diagnosis of Fibromyalgia because of it! And while many thyroid patients may be clear they have inflammation, others may have it with no clue!  See the newest page on Stop the Thyroid Madness concerning the problem of inflammation, how to detect it, and what you need to do about it.

24 Responses to “Exercise reduces T3, Vitamin C lowers high cortisol, Interesting theory about iodine…and more.”

  1. Jill

    I tested the theory that exercise immediately before your thyroid blood tests changed hormone levels. I had two tests done one with no exercise in the previous 5 days and the next one a week later. During that week, I ran 3 miles every other day for 6 days. So 9 miles total in the week with the last run about 15 minutes before being tested. The results were exactly the same. I was hoping for different results, because at the time I was under dosed by my doctor and he proceeded to reduce my meds even more. I now have a new doc and who has increased my dose and I feel much better.

  2. Katy

    I am on T3-only treatment, and have found that I need to take more T3 on days that I exercise.

    • Cindy

      Katy, that is very interesting! I have found exercise to be harder while on T3 only rather than NTH……maybe I just need to increase on those days to accomidate!

  3. machteld

    There are three components for my recovery in the last 12 months.
    After years of suffering serious adrenal fatigue caused by T4 only meds, culminating in high bloodpressure, constant heart palpitations at night and taking more anti-biotics and getting allergies to them than in the previous 60 years combined
    I started
    1) taking 1000 mg of vit C before going to sleep. It calmed down my heart immediately. I kept them on my night table and chewed one in the middle of the night if necessary.
    2) I changed taking my T3 to 4am, noon and 8pm.
    3) I take DHEA drops 2x4dropos a day out of a bottle containing 30ml total.
    and 2×12 drops of pregnenelone out of a bottle of 30ml total. The very low dose was the secret for me. I could not tolerate anything at that point.
    Now I am back to a much more normal life. I feel stable for the first time in years.
    The Vitamin C was a life safer.

    • Brenda

      This is my first time on the site. I would love to hear more about heart palpitations, Vit. C and anything else that will lower my cortisol. I’ve had Hashi for years, but have not been on any meds. My T4 is now low and I have a 2 cm by 2 cm nodule. The biopsy came back clean this week. I have a 19 year old son dying of lung and liver failure. Stress is high. Sleep is crucial, but my heart often goes crazy in the evening/at night. 2 questions.
      1) Why? What’s causing the rapid heart rate?
      2) Can you send me a link to understand what’s going on from what you’ve discovered about low functioning thyroid and high cortisol/adrenal activity (or bursts).
      Can’t thank you enough! I’ve already popped 1,500 mg of C.

      • Renee


      • sandy schmitt

        I too would like to know how to handle stress along with hypo/high cortisol? please,,,,

        • sandy schmitt

          also the rapid heartrate is caused by the high cortisol. the high cortisol wakes me every a.m. at 3. and no longer can sleep. I wish too there was a safe way to lower it. i have been on a supplement called cerenity pm with the phosphatidylserine but this will not let me sleep at night at all for the last week and i am exhausted. anyone have any ideas of what to do?

  4. Eve Ferguson

    Why do some countries recommend keeping natural “Thyroid” in the fridge but some do not???? I do now since I found at the end of my 3 month supply I had “a crash and burn” until I was on the new batch.

  5. Karen

    I think the T3 reduces after exercise because carbohydrates are the main fuel for this. Carbohydrates are needed for T4 to T3 conversion so as the carbs are used up for the exercise, it is not available for thyroid conversion. So if one is going to exercise, they would need to increase carbs to accommodate.


      seems to be true for me.. i am a runner and find the more miles i log the higher my carb intake has to be. i do just fine with very little carbs at all and only from non starchy veg when my exercise is minimal

  6. Sharon

    I was on Armour thyroid several years ago and it didn’t help, but I also had adrenal fatigue, which I think needed correcting before thyroid supplements would work. I felt much better after taking adrenal support. Now I know I’ve had Lyme disease for a long time, so that adds a lot of symptoms itself.
    I recently had a biofeedback scan done and it showed I have other parasites, insecticides, and other things in my system and explains how they block nutrients and other things that contributed to my current decline. I’ve been an organic gardener my entire life, so it was a little disheartening to see the pesticides show up. It shows viruses too, one of which was distemper. We had 2 cats that contracted it, so that’s likely where it came from. Any way…it just shows how many things impact our bodily functions.

  7. James Z

    “While our Paleolithic ancestors subsisted on a very low carbohydrate/high protein diet, the agricultural revolution about 10,000 years ago brought about a significant increase in dietary carbohydrate. These nutritional changes have increased T3 levels significantly. Higher T3 levels are associated with an enhanced T3 production and an increased iodine requirement. The higher iodine requirement exceeds the availability of iodine from environmental sources in many regions of the world, resulting in the development of IDD”

    It would be interesting to know what the prevalence of thyroid problems are around the world, and how this may relate to diet, pollution (Americans seem to be inordinately sicker on average than people in almost every other developed nation on this planet!), lifestyle, etc… I think the time has come to “run for the cause” every bit as much as we “run for the cure”! The Medical community always seems to have plausible explanations for every new illness that pops up, without ever knowing what the REAL CAUSE(S) are. Weird, I’m certain that it has absolutely nothing at all to do with the profit motive and the continued growth of the Medical Machine(sarc)!! Wake up people, we are being poisoned from every direction! Our food, our water, and the very air we breathe (here they have a winner, try and escape inhaling unfilterable nano-particles)!

  8. connie

    I dont know if anyone has ever heard of this before, but to help lower your cortisol without taking any supplement, you would try “Earthing”. There is a website for this. I purchased the book and one of the smaller earthing pads that I used when I slept. My sisters holistic doctor in Atlanta had told her of this and she shared it with me. Once I bought the ” Earthing pad” my cortisol went so far down that when my gyn at the time (last year) said she had NEVER seen anyone’s cortisol so low. Yes, my cortisol went way low. Now since she had done the one time blood draw and didn’t seem to informed on the cortisol testing of saliva, I just quit using the ‘Earthing pad’ but will have my adrenals and cortisol tested more in depth. Now I know alot of thyroid patients suffer lower cortisol. But if anyone has this problem, I can promise you the Earthing pad will bring it down. It is not electric, but runs on the earth’s current, like walking barefoot and you are exposed to the vibration which does wonderful things to a body. Anyhow, there’s alot of info on helping the thyroid as well.

    • Teri

      Connie, I find earthing fascinating!
      When my biorhythms go haywire and so does my sleep, time at the beach always corrects them and gets me in sync.
      I always assumed it was the negative ions and sun but earthing makes perfect sense!

      Never considered its affect on cortisol.
      Thanks for sharing!!

  9. Eaamon

    after being on this and many other web sites. the iodine thing makes me wonder how many self health GURUs have sea salt on their tables. they have all done them selves in by displacing the iodine in iodized salt. I did….thinking vitamins or veggies I eat will supply it all.

    • DSchwab

      Misconception that sea salt does not have iodine. Iodine is processed out of table salt and thus it needs to be added back.

      • Eaamon

        yes DSchwab, sea salt was the health fad in the 1980’s and many still think iodine free salt is the way to go…more healthy since it is natural. but as time goes on iodine from foods is becoming less and less as soils are depleted of it. the more I study iodine, it is the natural health way of being the bodies anti-biotic, angiogenesis (prevents cancer/tumor cells from growing a blood supply) and anti-yeast compound of everyone. just beware of sites over doing doses. I for one do not believe that sea salt has any iodine as the sea salt I have does not list it on the bottle.

        it is funny that it is not the first thing on this site that iodine or the lack of it might just be what some people really need.
        the US recommended daily intake should be 150 mcg……regular salt that is iodized does not give you but a smidge per dose. but you do get some.

        T4 has 4 iodide parts, T3 has only three and it is necessary for hypothyroid patients….maybe more than you know. you can check some of this out at wikipedia, browse ‘thyroid’ t3 and t4 and it’s relationship with iodine is partially explained…..

        the best way to get some might be kelp. but put ‘foods with iodine’ in your search engine.

    • Susan

      Studies show that only 10% of the iodine in iodine salt is actually absorbed by the body, and 96% of Americans are low on iodine. Symptoms: goiter, fatigue, infertility, retarded babies, fibrocystic breasts, heart problems, breast cancer.
      A lot of many is being spent trying to cure these ‘after-the-fact’, when they could all easily be prevented by taking Iodoral or eating more seafood and kelp.
      Read Dr.David Brownstein’s ‘Iodide’ book for more info, and Dr. Joel Wallach’s books for preventing other diseases (like strokes = lack of copper; early symptom is gray hair and spider veins).

  10. Maria

    *this is an extension of a very long post I tried to send twice, maybe it’s waiting for approval because of length?

    Also want to mention that I have tried several OTC desiccated supplements for adrenal and thyroid, colostrum and lactoferrin. All made me lethargic.
    I’m on a ton of vitamins and supplements that are specific to my symptoms and iodine protocol, now thanks to this thread, will be adding vitamin c. I have had a side effect of constipation, not sure if it’s the iron or the iodine, double dosing magnesium, not helping, hopefully vit c will do the trick.

  11. Anne

    I need information on hyperthyroidism. Now currently on medication and experiencing very bad symptoms.

  12. Anne

    Sorry, not currently on medication.

  13. A.omran

    May you please explain the full mechanism for cortisol reduction in low intensity exercise and increase in high intensity exercise ?

  14. A.omran

    May you please explain the full mechanism for cortisol reduction in low intensity exercise and increase in high intensity exercise?


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