More than 26 million Americans have thyroid disease, although at least 60% of them are unaware they have any issues. Many doctors do not test for thyroid conditions or use a full thyroid panel to correctly diagnose a thyroid condition. Women have a 75% higher risk of developing thyroid problems, and the majority of cases are believed to be autoimmune responses.
You can test your thyroid function at home. Let’s take a look at how to do this. Depending on the results, you may want to check in with your doctor to discuss a possible thyroid condition.
Thyroid hormone and body temperature
Thyroid hormone plays a key role in the metabolism of every cell of your body. It helps to increase the metabolic activity of most cells and helps to regulate the body’s temperature levels. When thyroid hormone expression is dysregulated, your body temperature will be off.
In addition, you may experience symptoms like unexplained weight gain, menstrual or fertility problems, fatigue, dry skin and hair, high cholesterol, and more.
Thyroid and basal body temperature (BBT)
A major clinical sign of hypothyroidism is low body temperature. Analyzing the body’s basal body temperature (BBT) through axillary (underarm) testing is an effective method to determine your thyroid function in an inexpensive, non-invasive way. Some research has been conducted on BBT that found it is highly correlated with low thyroid activity.
While the standard body temperature is 98.6 degrees F, the normal underarm temperature is 97.8-98.2 deg F. If your temperature is consistently under 97.4 deg F, then you most likely have under-functioning thyroid activity. If the temperature is consistently above 99 degrees then you may have hyperactive thyroid activity.
The importance of normal basal body temperature
Low body temperature can point to a possible thyroid or adrenal dysfunction. In addition, it can create an environment for other problems. Our body temperature is critical for circulation, enzyme activity, immune function, and more.
An abnormally low body temperature produces an environment that is welcoming to pathogens like viruses and bacteria. Our bodies respond to bacterial and viral infections with a high fever making the environment inhospitable to pathogens. And it activates powerful immune activities within the body.
In addition, enzymes are temperature-dependent and won’t function poorly at lower than optimal temperature ranges. A low-body temp will reduce enzyme activity which slows the body’s intracellular metabolism and causes an inability to buffer oxidative stress effectively. It also leads to poor digestion, liver metabolism and an inability to deactivate and excrete toxins from the body.
Instructions for the basal body temp
- Get an old-fashioned mercury thermometer or Galinstan and put it by your bedside.
- Shake it down to 95 degrees F.
- Before you get out of bed in the morning or eat or drink anything, put the thermometer in your armpit for 10 minutes and record the temperature.
- The temperature should be taken for 4 consecutive days.
- If you are using an oral thermometer in the mouth for this, you must realize that the oral temp is typically about ½ degree higher. So be sure to subtract ½ degree from your result to make it closer to your underarm temperature. If using the Galinstan or mercury thermometer in your mouth…leave it in for 5 minutes.
Other factors involved in BBT readings
If you have an infection or a fever, do not take the test as your temperature will naturally be higher than normal. Infections and fevers drive up body temperature and may cause a false negative. If you notice the temperature going up and down between days, it may be an indication of adrenal hormone dysregulation.
If your temperature is lower, it may be an indication of thyroid issues, but a blood panel should be done for confirmation. If your temperature is high, yet you have hypothyroid symptoms or have been diagnosed with hypothyroidism, it may be indicative of Hashimoto’s thyroiditis or autoimmunity against your thyroid.
In autoimmune-based hypothyroidism, your thyroid hormones may vary, and you have an increased risk of higher inflammation within the body. Both of these mechanisms can raise the BTT. High temperatures can also be a sign of anemia or low estrogen levels.
Using the BTT for thyroid and adrenals
An individual can use this test to help them find out about their thyroid function as well as adrenals. In fact, you can see how your supplement or medication dosage is supporting your body. Here are 5 ways this test can benefit your treatment.
- It can help you assess your adrenal function, which plays a role in the basal temperature as well. This is most notable in phase IIIA-IIID adrenal dysfunction.
- It can help you change the dosage of your adrenal supplements based on the results you are getting.
- After several days of taking thyroid medication or thyroid glandular, you should begin noticing an improvement in the temperature.
- It can help you change the dosage of your thyroid medication or supplement.
Using BTT to look at adrenal function
The adrenals work to increase blood flow throughout the body as cortisol works with its cousin aldosterone, which are both made in the adrenal cortex. Cortisol helps to maintain blood sugar, while aldosterone helps to retain sodium and maintain blood pressure. When you retain more sodium, you also retain more water, which increases blood volume and blood pressure. When you retain less sodium, we also retain less water, which decreases blood volume and blood pressure.
When people have hypertension or high blood pressure, they often take an angiotensin-converting enzyme inhibitor (ACE inhibitor) to lower aldosterone levels and therefore lower blood pressure. When the signaling process in the body, called the hypothalamic-pituitary-adrenal (HPA) axis is dysregulated, we can end up with either high or low cortisol/aldosterone levels.
Low blood pressure (under 100 systolic and 60 diastolic) is a common symptom for an individual with low cortisol, while high blood pressure (over 140 systolic and 100 diastolic) is common for individuals with high cortisol.
Testing your adrenals with BTT
The way most people experience low morning cortisol would be in an inability to get out of bed. If this is the case, it is most likely a low functional HPA axis in the morning.
To test your BTT to analyze cortisol levels throughout the day, follow the following strategy:
- 3 hours after waking
- 3 hours after that (6 hours after waking)
- 3 hours after that (9 hours after waking)
- Take these 3 temperatures and add them up and divide by 3 to get your daily average temperature (DATS).
- Do this for 5 days and analyze the results of each day. If any of the day’s temps are more than .2F off from another, it may be a sign of adrenal dysfunction.
- Do not test in the evening or at night because cortisol should normally be low at that stage. Cortisol should be at its highest in the morning and slowly taper down as the day goes on.
What is the best thermometer to use?
Most specialists believe that the digital thermometers are not accurate enough and the temp range can vary significantly. It is recommended to use the old-fashioned mercury thermometer. The downside of a mercury thermometer is that if it were to break, toxic mercury vapor would be released.
You might consider using a Galinstan, which is a liquid non-mercury thermometer that has a great degree of accuracy. If you are going to use a digital thermometer, this one seems to work well.
With the Galinstan or mercury thermometer, be sure to shake it down to 95F/ degrees the night before checking or if doing the adrenal test, right before testing. Be sure to hold it under your armpit for a full 10 minutes before checking. Be sure not to move around other than the lightest of movements as needed. If you have any questions about the readings, talk to your functional medicine doctor.