In my blog, you'll hear a lot about the stress hormone cortisol. If you have ever listened to a stress reduction briefing, or you exercise regularly, then you are likely aware of this hormone. However, what you might not be familiar with is cortisol's connection to the diseases that make up Metabolic Syndrome X. There is good evidence that cortisol is the "X" in Metabolic Syndrome X.
What is Metabolic Syndrome X?Metabolic Syndrome X describes a mysterious connection between heart disease, stroke, high blood pressure, abdominal obesity, diabetes, and high blood cholesterol. For someone to be diagnosed with Metabolic Syndrome, they must have three or more of the following risk factors: (1)
- Blood pressure equal to or higher than 130/85 mmHg
- Fasting blood sugar (glucose) equal to or higher than 100 mg/dL
- Large waist circumference (length around the waist):
- Men - 40 inches or more
- Women - 35 inches or more
- Low HDL cholesterol:
- Men - under 40 mg/dL
- Women - under 50 mg/dL
- Triglycerides equal to or higher than 150 mg/dL
The most interesting part about these risk factors is that they tend to appear together. For instance, if you are obese, then you are more likely to have (or develop) poor blood sugar control, high blood triglycerides, and high blood pressure. (2) Because these risk factors tend to appear (and disappear) together, they likely have a common cause.
While searching for this cause, I happened to read The Potbelly Syndrome by Russell Farris. It was here that I discovered that cortisol was likely the central cause of Metabolic Syndrome. I now believe that chronic stress (from any source) can cause chronic elevation of cortisol, which can cause serious dysfunction in the body. This dysfunction manifests itself as heart disease, stroke, high blood pressure, abdominal obesity, diabetes, and high blood cholesterol (as well as muscle wasting, low energy, accelerated aging, osteoporosis, suppressed immune system, and cancer).
HPA axis) and produced by the adrenal glands. This hormone has several important functions in the body: (3,4)
- It is a "fight or flight" hormone that helps the body deal with the effects of stress.
- It controls blood sugar, gluconeogenisis, blood pressure, and inflammation.
- It keeps the immune system from getting too aggressive.
- It regulates energy availability.
- It causes a person to wake from sleep.
- Poor Diet. A diet that is devoid of essential nutrients, antioxidants, and soluble fiber and filled with toxins and easily digestible fuels can cause digestive distress and inflammation. Some dietary toxins (e.g., gluten, lectins, rancid fats, and high-omega-6 oils) can cause a constant immune response. (5) If a person constantly eats a poor diet, then cortisol is constantly required to control both inflammation and the immune system. (3)
- Chronic Infections. Accumulation of middle path infections increases your infection load. Each chronic infection you acquire requires cortisol to suppress an aggressive immune response. As you collect more and more middle path infections, your body has to produce more and more cortisol to control the resulting inflammation. This further suppresses the immune system and makes you more prone to further middle path infections.
- Chronic Excess Exercise. Excessive high-intensity or heavy exercise can cause too much wear and tear on the body, which causes a stress response. If this stress response is chronic, then a person will constantly have too much cortisol circulating in their blood, leading to poor energy levels, lack of progress (known as plateauing), and muscle loss (known as overtraining).
- Constant Mental Stress. Any mental stress (e.g., worry, anxiety, dread, fear) can cause a stress response. If this mental stress is chronic, then the hypothalamus will constantly react to this stress, causing a chronic elevation of cortisol.
If you are healthy and not experiencing chronic stress, then cortisol does all of its jobs without causing dysfunction. However, when cortisol levels are chronically elevated (or insufficient), lots of things go wrong in the body.
Cortisol and Metabolic Syndrome XI will go more in depth into how cortisol can cause most of the dysfunctions associated with Metabolic Syndrome in later posts, but here's a sneak peak until then:
- Blood Pressure-Cortisol is used to control blood pressure. When present in the blood, blood pressure will rise. If cortisol is chronically elevated, then it can chronically elevate blood pressure. (4,6)
- Poor Fasting Blood Sugar and Type 2 Diabetes-Cortisol tells liver and muscle cells to release their stored sugar (glycogen) to prepare for either fight or flight. This sugar surge makes sure that the brain has enough energy to out-think the cause of the stress reaction. However, when cortisol is chronically elevated then it constantly forces these cells to push sugar into the blood. This causes higher-than-normal blood sugar levels that have to be controlled by higher levels of insulin. Theoretically, this means that when the pancreas can no longer overpower the counter-regulatory effects of cortisol, a person develops Type 2 diabetes. (4,6)
- Large Waist Circumference and Obesity-Because cortisol forces energy storage cells (e.g., liver, muscle, and fat cells) to release their energy, it naturally counter-regulates insulin. This means that cortisol directly causes insulin resistance. (4) For reasons that are not fully understood, chronically elevated levels of cortisol force insulin to store energy (blood sugar and free fatty acids) in visceral fat (which is located primarily in the abdomen) as opposed to subcutaneous fat (which is under the skin). As more and more energy is stored in visceral fat (where it doesn't belong), a person's waist grows. (6)
- Low HDL Cholesterol-The liver produces and regulates high-density lipoprotein (HDL) cholesterol, often called "good" cholesterol. Excess levels of cortisol have been shown to cause liver dysfunction (hepatic insulin resistance and non-alcoholic fatty liver disease). An indication of a poorly performing liver is low HDL. This means that chronically elevated levels of cortisol can be a cause of chronically lowered levels of HDL. (6)
- Heart Disease and Stroke-Cortisol's involvement in heart disease is a bit complicated and involves middle path infections (those infections that your immune system can't kill and don't kill you either). Extra cortisol has to be produced to control your immune system every time you get infected with a middle path infection (e.g., CPN). With your immune system controlled by cortisol, a middle path infection makes its way to your arteries where it takes up residence. Over decades this infection multiplies while your immune system continuously attacks it, producing atherosclerosis. This infection will eventually start to cause infected arteries to close. It can also create a kind of boil that can rupture, dumping its contents into the blood and causing a heart attack or stroke. (6,7)
ConclusionToday, we are plagued by degenerative diseases like heart disease, stroke, diabetes, high blood pressure, and obesity. Up until recently, it was assumed that these diseases are the natural consequence of living longer. But this is far from certain: There are much better explanations for these diseases that have nothing to do with age.
One very good explanation is the chronic elevation of the stress hormone cortisol. In an era of constant stress, poor diets, and sedentary lifestyles, humans living in modern societies are bombarded with stressors that constantly elevate cortisol. When constantly elevated, cortisol can cause many of the degenerative diseases attributed to aging. It is also likely central to Metabolic Syndrome X, which is the relationship between heart disease, stroke, diabetes, abnormal blood cholesterol levels, high blood pressure, and obesity.
Understanding cortisol's involvement in Metabolic Syndrome also means that you can seriously reduce (or eliminate) your risk of developing diabetes, heart disease, stroke, high blood pressure, and obesity by switching to the low-stress Paleo-like diet and lifestyle. These diet and lifestyle changes can improve your nutrition, reduce your chronic stress, and re-enable your immune system, all of which can allow your body to reverse much of the damage caused by years of exposure to excess cortisol.