How Too Much Exercise Can Make You Gain Weight

Exercise cause weight gain

Until I turned 27, I had never had an issue with my weight. I was eating a healthy diet and exercising 6 days a week, doing high intensity training for over an hour each day. Yet I was gaining more and more weight, 30 pounds to be exact! I couldn’t understand why I was working so hard and getting the opposite results of all my efforts. I had some other symptoms creeping on too, like extreme fatigue and more and more hair loss. At first, I chalked it up to being in medical school and studying for about 5 hours a night after my 9-hour school days. Plus, all the doctors I went to for help with this told me I was fine.

At this point I was running about 5-6 miles a day and I started to get shin splints, making my runs very painful. I didn’t want to stop running because I was worried I was going to gain even more weight, but knew I had to rest for a while so my body could heal. I decided to start doing Pilates so that I could at least get some type of exercise in. After a couple weeks of doing Pilates with no running I started to lose some weight. This was so weird to me, I thought it had to be a fluke!

I decided at this point that there had to be something to this, so I went on a long search for an answer. This is when I found a functional medicine practitioner that did much more thorough testing than the other doctors I had been to that just blew me off. After thorough testing was done on my adrenal glands and my thyroid gland, I learned that my cortisol was really high. See, cortisol is the stress hormone that the adrenal glands produce. You will never guess what the biggest sign of high cortisol is…Yep, that’s right, weight gain!! The high intensity exercise I was doing was pushing my cortisol higher and since the adrenal glands and the thyroid gland work together, this was causing my thyroid to under function as well.

The adrenal glands and the thyroid gland run on the same axis, HPAT axis (Hypothalamic-Pituitary-Adrenal-Thyroid), so one can greatly affect the other. When cortisol is high, it not only can cause weight gain, but it can also cause fatigue, insomnia and a number of other unwanted symptoms. Strenuous exercise can cause an increase in cortisol levels. Strenuous exercise can also cause suppression of the immune system. Since about 97% of thyroid disease is autoimmune in nature, this can also cause strain on the thyroid gland leading to weight gain.

What is Considered Strenuous Exercise?

Having an elevated heart rate for more than a few minutes at a time is considered strenuous when there is adrenal insufficiency. You should be able to carry on a conversation the entire time you are training. Interval training is a better option because you are doing about 1 minute of high intensity training followed by a minute or so of rest. HIIT training and Tabata training are two popular methods of doing this type of burst training. For some with high cortisol and/or a thyroid condition, you may need to start with something like yoga or Pilates until the adrenal glands and thyroid gland have been supported for a period of time.

What Can You do to Support the Adrenal and Thyroid Glands?

Since these two glands respond so negatively to stress, this is where you must start when supporting these glands. There are many different types of meditation that more and more people are turning to for stress relief like mindfulness training, Vedic meditation, Ziva mediation and more. These types of mediation can help us teach or bodies to respond differently to the daily stresses of life. It has been scientifically proven to work and I highly urge you to give one of these a try. They usually consist of committing to 1-2 sessions of about 20 minutes of meditation each day. When people hear the word meditation, some think it is a spiritual process. It is actually more about brain and body retraining instead.

Next up is blood sugar control. Controlling your blood sugar with diet is key to controlling cortisol levels. Blood sugar greatly affects cortisol and vice versa. High cortisol tends to lead to high blood sugar, which again, can lead to weight gain. A diet low in sugar and higher in healthy fats like avocados, coconut oil, ghee and lean protein like chicken, turkey, grass-fed beef or bison, with tons of fibrous veggies like leafy greens, broccoli and cauliflower is the best way to do this.

How much sleep you get each night also plays a huge role in your weight. Sleep deprivation can raise cortisol levels and make you more prone to making bad choices with diet. Getting plenty of sunlight during the day and keeping things dark at night will help to keep your circadian rhythm in line, helping you achieve a good night’s sleep. Making sure you are in bed by 10pm is the best way to ensure that you will get an adequate amount of sleep. I recommend doing something calming like reading while diffusing some essential oils before bed instead of watching TV or working on your computer or phone.

Adaptogenic herbal supplements like ashwagandha and holy basil to name a few, can also help to keep cortisol levels from going too high or too low. Selenium rich foods like brazil nuts and organ meats and iodine rich foods like seaweed, raw dairy and eggs can give your thyroid the support it needs as well. I have also found taking adrenal and thyroid glandular supplements to be very beneficial to supporting these glands as well. I would recommend working with a functional medicine doctor to help you with dosing of these glandular supplements however because sometimes they can be too powerful and push the cortisol or adrenal hormones too high.

So, if you are like I was, and feel like all your hard work in the gym is not paying off, high cortisol may be the culprit. I recommend testing your cortisol levels using the DUTCH test which uses dried urine metabolites to determine your free and total cortisol levels. This test has the capability of measuring many other factors like sex hormone levels, oxidative stress levels, methylation status, neurotransmitter levels and more. I use this test in my practice and believe it is far more accurate than blood or saliva testing.

In The 30-Day Thyroid Reset Plan“, I talk more about what types of exercise are best for you cortisol levels. I also include a quiz to help you figure out if your cortisol levels are high and go in to great detail on what to do to support the adrenal and thyroid glands with my 30-day plan. Check it out here!







Hi, I am Dr. Becky Campbell. I work with men and women who’ve had a health set back and are willing to do whatever it takes to reach optimal health so they can perform their best in their careers and be fully present with their family again.

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