Your thyroid plays such a tremendous role in your metabolism.1 When your thyroid is slow, it can impair your metabolism by up to 30%.

In this article, we will discuss how optimizing your exercise routine, TSH levels, and iodine intake can help restore you back to your normal metabolism.

Exercise & Metabolism

Exercise is very important for boosting metabolism and helping weight loss.2 In fact, exercise has many additional benefits, including:

  • Releasing endorphins
  • Improving insulin sensitivity
  • Helping with sleep

Key Insight: One of the pitfalls of exercise, though, is that it also makes us hungrier. The threshold for exercise making us hungry is right around 300 calories for women.

On top of this, an increase in appetite often outweighs increased metabolism. This equals 3 miles walking or running, up to 45 minutes of gym activities, or 8 miles of cycling.

Ultimately, a variety of exercise is important. No one type is “good” or “bad.” What you have to do is pick an exercise regime you enjoy doing and cycle through different types of exercises.

Some of the exercises you should be considering include:

  • Steady-state cardio
  • Flexibility training
  • HIIT
  • Strength training
  • Long slow distance

Bottom Line: Interested in learning more about exercises for thyroid disease? We have written at length about it before and would love for you to learn more. (Read: What is the best exercise for thyroid disease)

TSH & Metabolism

There is a dramatic difference between normal and optimal ranges for thyroid dosing. Although you may fall within a normal reference range on your labs, you could still be underdosed.3

The reference ranges on labs are wide – up to 4.5, optimal TSH falls between 0.5 – 1.5 (Read: The right thyroid dose for better energy and weight loss).

Body-Mass Index

Within a normal range, your TSH is related to your body-mass index (BMI).4 Dialing in your TSH will help with maintaining an ideal weight. Overall, an Increase in TSH is correlated with an increase in weight.

Elevations of TSH in the upper half of the reference range have been shown to be associated with a risk for carbohydrate and lipid metabolism disorders in a recent study of teenagers.5 In turn, this increases your risk of metabolic syndrome.

Lower Iodine & Metabolism

Iodine is crucial for proper thyroid function. Here’s the thing, though: too much or too little iodine is harmful because it has a very narrow therapeutic index. This is what we know as the Wolff Chaikoff effect – above 300 mcg iodine can inhibit thyroid function.6,7

Key Insight: 100-300mcg a day is the sweet spot which you typically should get with a day’s food intake.

While iodine deficiency is possible, it is very rare in America. Therefore, excess supplementation of iodine outside of the diet will place most Americans over the recommended limit.

Some common sources of iodine include:

  • Supplements
  • Multivitamins
  • Thyroid medications
  • Bakery items (dough conditioners)
  • Dairy
  • “Sea veggies”

Please keep in mind that it is important to remember that natural desiccated thyroid (NDT) does contain iodine and must be taken into consideration when taking supplements with additional iodine.

Bottom Line: Too much iodine is dangerous, especially in the long run, and can cause health complications (like goiters). That is why more is not better. When it comes to our supplements, we keep them iodine-free (Iodine free supplements).

NDT & Weight Loss

At the same dose, NDT is more effective than synthetic thyroid medication for weight loss.8

NDT is a combo of:

  • T4
  • T3
  • T2
  • T1

Ultimately, this provides comprehensive thyroid support and benefits to your metabolism.

When we think of thyroid regulation, we are aware of T3 and T4 but often forget about T2 which has metabolic effects.9 With synthetic thyroid options, you will not have the additional benefit of T2 (Read: How to lose weight with thyroid disease).

Bottom Line: There are a variety of NDT options on the market, making the switch is relatively simple by seeing a qualified physician – like the ones at Integrative Health (Read: The complete thyroid medication guide).

Your Thyroid & Your Metabolism

An underactive thyroid can slow metabolism, and making simple changes can boost your metabolism. Here are just some of the things we have covered today, and what you should take with you when it comes to making changes to your health:

  • Being aware of the amount and type of exercise you are performing
  • Optimizing your TSH score
  • Lowering your overall intake of Iodine
  • If you are on synthetic thyroid medication, asking your doctor about changing to natural desiccated thyroid

Talk to Your Doctor

Make sure to always speak to your doctor before deciding on a treatment option or making changes to your treatment plan. If you’d like to speak to a professional, the doctors at IH would be happy to chat. Please feel free to reach out to us today (Click Here).


1. Mullur R, Liu Y-Y, Brent GA. Thyroid hormone regulation of metabolism. Physiol Rev. 2014;94(2):355-382. doi:10.1152/physrev.00030.2013

2. Donnelly JE, Honas JJ, Smith BK, et al. Aerobic exercise alone results in clinically significant weight loss for men and women: Midwest exercise trial

3. Obesity. 2013;21(3):E219-E228. doi:10.1002/oby.20145

4. Chakera AJ, Pearce SHS, Vaidya B. Treatment for primary hypothyroidism: current approaches and future possibilities. Drug Des Devel Ther. 2012;6:1-11. doi:10.2147/DDDT.S12894

5. Nyrnes A, Jorde R, Sundsfjord J. Serum TSH is positively associated with BMI. Int J Obes. 2006;30(1):100-105. doi:10.1038/sj.ijo.0803112

6. Korzeniowska KA, Brzezinski M, Szarejko K, et al. The association of thyroid-stimulating hormone (TSH) and free thyroxine (fT4) concentration levels with carbohydrate and lipid metabolism in obese and overweight teenagers. Endokrynol Pol. November 2018. doi:10.5603/EP.a2018.0090

7. WOLFF J, CHAIKOFF IL. The temporary nature of the inhibitory action of excess iodine on organic iodine synthesis in the normal thyroid. Endocrinology. 1949;45(5):504-513. doi:10.1210/endo-45-5-504

8. WOLFF J, CHAIKOFF IL. The inhibitory action of excessive iodide upon the synthesis of diiodotyrosine and of thyroxine in the thyroid gland of the normal rat. Endocrinology. 1948;43(3):174-179. doi:10.1210/endo-43-3-174

9. Hoang TD, Olsen CH, Mai VQ, Clyde PW, Shakir MKM. Desiccated Thyroid Extract Compared With Levothyroxine in the Treatment of Hypothyroidism: A Randomized, Double-Blind, Crossover Study. J Clin Endocrinol Metab. 2013;98(5):1982-1990. doi:10.1210/jc.2012-4107

10. Hernandez A. 3,5-diiodo-L-thyronine (t2) in dietary supplements: what are the physiological effects? Endocrinology. 2015;156(1):5-7. doi:10.1210/en.2014-1933