Maybe you are one of the many people that say that they have a slow metabolism. But how can you know for sure? One way is to see if you exhibit some of the signs of a low metabolism. This includes having chronic low energy and feeling cold, particularly in your hands and feet. Another way is to take some simple measurements to make an assessment of your metabolism at home. In this article I will describe two basic tests for metabolism that you can do at home.
The information I share in this article is inspired by the work of researchers such as Broda Barnes and Ray Peat. They were amongst the first scientists to promote this test for metabolism in the health sphere. These guys were way ahead of their time and really were the forerunners of the “pro-metabolic” movement. Since then, many others have shared or built on their theories. I have learned from the ideas of Danny Roddy, Matt Stone, Keith Littlewood and Emma Sgourakis to name a few.
I will link other peer-reviewed sources of information at the bottom of this post. Definitely check those out if you are interested in reading more into the science of this test for metabolism!
Link between slow metabolism and thyroid function
The underpinning theory is that your metabolic rate is driven by your thyroid function. A sluggish thyroid results in a “slow metabolism” otherwise known as hypothyroidism. Conversely, an over-active thyroid means a fast metabolism, aka hyperthyroidism. For optimal health and wellbeing, you want your thyroid to be functioning in the healthy range. This means producing normal amounts of thyroid hormones which are also being used appropriately by your cells.
Dr Denis Wilson, claimed that of every 100 patients with a low body temperature and hypothyroid symptoms, only 5 will show up as having abnormal TSH levels and therefore a diagnosis of hypothyroid. He labelled this condition of low metabolism symptoms with normal thyroid test results as Wilsons Temperature Syndrome. He believed that basal body temperature was a good test for metabolism function, regardless of blood levels of thyroid hormones.
Reference: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4566469/
I have to make clear that this is not an accepted diagnosis according to most medical professionals. However, I view it alongside Adrenal Fatigue as a description of a common adaptive state of the body functions which leads to particular symptoms. Perhaps the diagnosis is not accepted but if the treatment works then I don’t see it as a problem.
Interestingly, both slow metabolism and adrenal fatigue are conditions primarily linked to stress! But we won’t go there for today. We will quickly review the common signs and symptoms of a slow metabolism. Then I will introduce you to the two tests for metabolism you can take an home.
Signs and symptoms of low metabolism
To clarify, symptoms are health effects identified by the individual whereas signs can be observed and measured by others. Often experiencing symptoms like fatigue and low energy can be frustrating. This is because you are made to believe by doctors and others that it is all in your head. There are many symptoms related to a low metabolism. Often they go unnoticed because they are subtle or seen as normal.
Broda Barnes in his book Hypothyroidism: The Unsuspected Illness, argued that many common symptoms are a result of sub-clinical hypothyroidism. Some of the symptoms associated with a low thyroid function are:
- Fatigue
- Headaches
- Depression
- Anxiety
- Low libido
- Constipation
- Low mood
- PMS
- Insomnia
- Easy weight gain
Reference: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4566469/
If you are experiencing several of these symptoms on a regular basis, potentially you are dealing with a low metabolism.
Two major signs of a low thyroid function and slow metabolism are low body temperature and low pulse rate. These two signs are consistently associated with the symptoms above. Measuring these two indicators can therefore be a helpful test for metabolism function. Other signs include dry skin, dry hair and slow growing or brittle nails. All of the signs and symptoms are a result of reduced cellular respiration and energy generation.
Now let’s see, is your metabolism low?
Test for metabolism 1: Basal body temperature
Broda Barnes pioneered low basal body temperature as a sign of hypothyroidism, aka a slow metabolism. Therefore, the first of the two test for metabolism is to measure your core body temperature and compare it to the healthy range. Do this upon waking every day for a week and record your results. You can use any thermometer just make sure to warm it up first to avoid skewing your measurements.
A healthy functioning metabolism should result in an oral temperature of 36.6°C or above (armpit temperature is usually approx. 0.3-0.6°C lower). If your temperature is consistently below this, it may be a sign of a low metabolism. Especially if you also have some of the signs of a low metabolism. Remember, this is your temperature upon waking. After eating, drinking and moving your body, your temperature should increase above this minimum.
For females, remember that your basal body temperature can increase by up to 0.5°C following ovulation. It then then decreases again once menstruation begins. This is due to an increase in metabolic rate during the luteal phase of your menstrual cycle. The numbers above refer to your temperature in the first half of your cycle. Make sure you do the test for metabolism before ovulation for an accurate assessment.
Reference: https://www.ncbi.nlm.nih.gov/books/NBK546686/
As a side note, observing this temperature rise is a good sign that you are ovulating. This is a good sign of a healthy menstrual cycle and fertility!
Test for metabolism 2: Resting pulse rate
The second test you can use to determine whether your metabolism is low is to measure your resting pulse rate. Measuring heart rate is a well established method for determining metabolic rate. A pulse rate of 70-85 beats per minute (bpm) is generally an indicator of a healthy metabolism. The exact number range differs but there is agreement in the pro-metabolic world that a pulse rate of <60bpm is a sign of low metabolism. Especially when combined with low temperature and other signs of low thyroid function.
Reference: https://www.sciencedirect.com/science/article/pii/S1095643310004988
Although many health professionals state that a pulse rate <60bpm is a sign of fitness, this is not the whole truth. Yes, it is true that athletes have a low pulse rate as a result of their fitness. However, fitness and health do not always go together! A low pulse rate, or bradichardia is a sign of metabolic adaptation. Therefore pulse rate can be useful test for metabolism. That is a modification of the metabolic processes in order to do more with less energy input. This is a useful adaptation in athletes as it allows them to perform at a higher level in sport. But it says nothing about their general health.
For example, many female athletes suffer from the Female Athlete Triad. This is a combination of low energy availability, disrupted menstrual cycles and decreased bone mineral density. Usually this is a stress state caused by too much exercise and not enough energy intake. This can affect any woman who is very active and not fueling correctly, not only professional athletes.
Reference: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3435916/
But isn’t a high pulse rate unhealthy?
It does get a little complicated as increasing resting heart rate is also associated with increased incidence of metabolic syndrome. According to the NHS, metabolic syndrome is “the medical term for a combination of diabetes, high blood pressure (hypertension) and obesity“. This test for metabolism is not perfect and the results need to be taken in context of an individuals’ lifestyle. That is why it is important to work with a health professional.
Having a high temperature and pulse rate whilst eating well and being active is different than achieving the same outcome by being sedentary and eating unhealthy food. The best thing to do is keep an eye on your other health markers such as blood pressure, glucose and weight alongside your temperature and pulse to find the lifestyle that works best for you.
What if the test for metabolism shows it is slow?
If you try out these two test for metabolism and think that you do have a slow metabolism, what can you do about it? I shared some simple tips for how to speed up a a slow metabolism in a previous post. In that post I also describe some of the potential causes of a low metabolism so make sure you check it out. You can also try incorporating my top foods to increase your metabolism into your daily diet. For individual support in discovering the best lifestyle to support your body, please reach out.
Over to you…
If you would like to work with me to balance your hormones and improve your health, contact me to set up a free 15 minute discovery call. I am a nutritionist, yoga teacher and women’s wellness coach. We work together using a combination of modalities to support your individual needs and help you to feel your best.
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