Category Archives: Inflammation and Stress

What can cause low cortisol levels?

Cortisol is a steroid hormone that has many important roles in the body, including of course its most well-known role as part of the stress response. Receptors that cortisol can bind to are found in almost all tissues in the body, which means that cortisol is able to affect nearly every organ system (1).

What are the functions of cortisol?

  • Controls the inflammatory response in an immune response
  • Cortisol surge helps provide energy during stressful situations
  • Role in the metabolism of fats, protein, and carbohydrates
  • Helps control blood pressure and salt and water balance
  • Involved in memory formation
  • Enhances the activity of epinephrine (adrenalin)
  • Supports developing fetus during pregnancy

How are cortisol levels controlled?
Cortisol is synthesized from cholesterol in the adrenal glands, with secretion controlled by the HPA axis. The HPA axis is a combination of glands that includes the hypothalamus, the pituitary gland, and the adrenal gland. This HPA axis follows a circadian rhythm, which means that cortisol levels are generally higher in the morning and lower at night (1).

When the hypothalamus detects low cortisol, low blood sugar, or times of stress, it releases corticotropin-releasing hormone (CRH), which signals for the pituitary to release adrenocorticotropic hormone (ACTH). ACTH then acts on the adrenal gland to trigger the synthesis and secretion of cortisol. Elevated cortisol levels inhibit the release of CRH and ACTH, providing a negative feedback loop to control cortisol levels (1).

What can cause low cortisol levels?
Low cortisol can be caused by different abnormalities in the HPA axis.

Primary adrenal insufficiency (Addison disease) is when there is an issue with the adrenal gland that inhibits cortisol production and release. This is most commonly caused by an autoimmune reaction (where the body’s own cells target and destroy cells in the adrenal gland), but can also be due to cancer, an infection (e.g., tuberculosis, AIDS, syphilis), an inherited disorder, drug use, or some other disease (2). Damage to the adrenal gland cells also affects the production of mineralocorticoids (e.g., aldosterone that control blood pressure) and sex hormones (e.g., testosterone and estrogen that are produced in low levels in the adrenal gland) (3).

Secondary adrenal insufficiency occurs when the pituitary gland does not produce enough ACTH; hence there is reduced stimulation of the adrenal gland and less cortisol produced. This is commonly caused by chronic exogenous glucocorticoid use but can also be due to pituitary disease, pituitary tumors or trauma, other infections (e.g., meningitis), or genetic disorders (1,2).

Tertiary adrenal insufficiency is an abnormality one step further back when the hypothalamus does not release enough CRH, therefore less stimulation of the pituitary gland, and subsequently less stimulation of the adrenal gland and less cortisol produced. It is most commonly caused by chronic exogenous glucocorticoid use, and can also be due to hypothalamic tumors, infections, and trauma (2).

What are the symptoms of low cortisol?
Generally, the symptoms of low cortisol are quite similar regardless of the cause (2). Symptoms can include:

  • Weakness
  • Fatigue
  • Weight loss and anorexia
  • Abdominal pain
  • Low blood pressure
  • Salt craving
  • Nausea
  • Vomiting
  • Diarrhea (may alternate with constipation)
  • Diminished sex drive
  • Menstruation may stop in women
  • Less pubic hair
  • Low blood sugar

Primary adrenal insufficiency is also characterized by hyperpigmentation of the skin. This is due to increased production and secretion of ACTH from the pituitary gland, as there is not enough cortisol present for the negative feedback loop to be working effectively. This hyperpigmentation does not occur in secondary and tertiary adrenal insufficiency as ACTH production is not increased (2).

The onset of adrenal insufficiency is often gradual, particularly for primary adrenal insufficiency, when more than 90% of the adrenocortical tissue is lost before symptoms occur. Often an illness or some other stress is what triggers an adrenal crisis, typically characterized by shock, and then other symptoms also become apparent (2).

How is adrenal insufficiency diagnosed?
There are three parts to an adrenal insufficiency diagnosis:

  • Demonstrating low cortisol levels: Serum cortisol levels < 3 µg/dL (80 nmol/L) at 8 am are strongly suggestive of adrenal insufficiency, while <10 µg/dL (275 nmol/L) make the diagnosis likely. Low salivary cortisol can also be used for a diagnosis (2). We offer a test of serum cortisol levels from a self-collected finger-prick blood sample. Our cortisol test is available here.
  • Determining whether the cortisol deficiency is due to primary, secondary, or tertiary adrenal insufficiency: This involves various different analyses, including measuring ACTH and CRH levels, and insulin tolerance tests (2).
  • Determining the cause: Again, various different analyses may be required here, including autoantibody screens and CT and MRI imaging (2).

1. Thau L, et al. Physiology, Cortisol. StatPearls [Internet].
2. Nicolaides NC, et al. Adrenal Insufficiency. Endotext [Internet].
3. Grossman AB. (Reviewed Oct 2020). Addison Disease. Merck Manual Consumer Version.

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C-Reactive Protein (CRP) Quick Facts

What is C-reactive protein (CRP)?
C-reactive protein (CRP) is a protein in the blood that non-specifically increases during inflammation and infection, as well as following a heart attack, surgery, or trauma. In many instances, tissue damage causes a significant spike in the blood concentration of CRP. However, even just minimal but persistent levels of inflammation result in small CRP increases.

Why measure CRP levels?
CRP is a very sensitive marker for inflammation and infection. It tends to rise before any other symptoms (e.g. fever and pain) occur, meaning it is an excellent option to detect underlying inflammation or an infection that is yet to cause any health issues.

What is the link between CRP and heart health?
There are numerous risk factors associated with heart (cardiovascular) disease, including high cholesterol, high blood pressure, being overweight, and diabetes. However, many individuals who develop cardiovascular disease do not appear to have any of the obvious risk factors (1).

The development of a high sensitivity CRP assay has allowed for the identification of individuals that have CRP levels within the higher end of the reference range (3-10 mg/L), who are not identified in standard wide-range CRP assays (2). These slightly elevated CRP levels in otherwise healthy individuals are indicative of the development of atherosclerosis (cholesterol deposits and plaque in the blood vessel walls) and help to predict the future risk of heart attack, stroke, and peripheral artery disease (3).

In addition, measurements of CRP are useful in patients who have already suffered a myocardial infarction. Elevated CRP in these patients is associated with subsequent risk of major adverse cardiovascular events and death (4).

Ways to lower CRP
Non-pharmacological methods for reducing CRP (and the risk of heart disease) include aerobic exercise, abstaining from smoking, losing excess body weight, and following a heart-healthy diet with whole grains, reduced unhealthy fats and sodium, and lots of fruits and vegetables. Various medications are also available that have been shown to reduce CRP levels, including statins, aspirin, and vitamin E (5).

Is CRP elevated in other health conditions too?
Yes, elevated CRP is not specific to just heart health. CRP values greater than 10 mg/L occur due to infections and diseases that cause inflammation, such as:

  • Cancer
  • Lupus (immune system disease)
  • Rheumatoid arthritis (swelling in the joints)
  • Inflammatory bowel disease
  • Osteomyelitis (bone infection)

It is important to note that although CRP tests are very useful to detect inflammation, they do not specify where the inflammation is located or what is causing it. Other tests will be required for additional information on the source and cause of the inflammation.

1. Fonseca FAH, and de Oliveira MC. (2016). High-Sensitivity C-Reactive Protein and Cardiovascular Disease Across Countries and Ethnicities. Clinics (Sao Paulo). 71(4), 235-242.
2. Pearson TA, et al. (2003). Markers of Inflammation and Cardiovascular Disease, Application to Clinical and Public Health Practice, A Statement for Healthcare Professionals from the Centers for Disease Control and Prevention and the American Heart Association. 107(3), 499-511.
3. Kamath DY, et al. (2015). High sensitivity C-reactive protein (hsCRP) & cardiovascular disease: An Indian perspective. Indian J Med Res. 142(3), 261-268.
4. Carrero JJ, et al. (2019). hsCRP Level and the Risk of Death or Recurrent Cardiovascular Events in Patients with Myocardial Infarction: a Healthcare‐Based Study. JAHA. 8.
5. Prasad K. (2006). C-reactive protein (CRP)-lowering agents. Cardiovasc Drug Rev. 24(1): 33-50.

How does stress increase cortisol levels?

Cortisol is widely known as the “stress hormone” and for good reason, as stress triggers a surge in cortisol. Cortisol also influences various other functions throughout the body too.

How are cortisol levels controlled?
Cortisol is a steroid hormone synthesized from cholesterol in the adrenal glands, with secretion controlled by the HPA axis. The HPA axis is a combination of glands that includes the hypothalamus, the pituitary gland, and the adrenal gland. This HPA axis follows a circadian rhythm, which means that cortisol levels are generally higher in the morning and lower at night (1).

When the hypothalamus detects low cortisol, low blood sugar, or times of stress, it releases corticotropin-releasing hormone (CRH), which signals for the pituitary to release adrenocorticotropic hormone (ACTH). ACTH then acts on the adrenal gland to trigger the synthesis and secretion of cortisol. Elevated cortisol levels inhibit the release of CRH and ACTH, providing a negative feedback loop to control cortisol levels (1).

What are the roles of cortisol?
Cortisol mediates the stress response, as well as helping regulate metabolism, the inflammatory response, and immune function. In times of stress, a surge in cortisol helps provide energy to the body by increasing blood sugar through gluconeogenesis (synthesis of ‘new’ glucose). Glucose is especially important as an energy source for the brain, helping to give that extra mental boost, such as when there is an important deadline approaching!

Cortisol is also involved in the metabolism of fat, protein, and carbohydrates. It helps control blood pressure and is even involved in memory formation. In addition, cortisol enhances the activity of epinephrine (adrenalin), which is what causes a faster heart rate and faster breathing in times of stress (1,2).

What happens if cortisol levels stay high for a long time?
Usually, cortisol only remains elevated for a few hours after a stressful event. However, in people who are suffering from chronic (long-term) stress, cortisol levels can remain elevated for several months. These persistently elevated levels of cortisol can increase the risk of various health complications, including anxiety, depression, digestive problems, weight gain, and insomnia (2).

1. Thau L, Gandhi J, Sharma S. (2020). Physiology, Cortisol. [Updated 2020 May 29]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan-.
2. What is Cortisol? (Nov 2018). Hormone Health Network, Endocrine Society.

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How to keep a healthy heart

Heart disease is the most common cause of death in the United States (1) and the second leading cause of death in Canada (2). Approximately 18.2 million adults in the United States have coronary artery disease (the most common type of heart disease), and every year about 655,000 Americans die from heart disease (1).

One of the main reasons for these very high numbers is that people are following lifestyles that are harmful to their heart health and overall health too. Following a heart-healthy lifestyle not only reduces your risk of heart disease but also lowers the risk of other complications including type 2 diabetes (3).

Understand your risks
First up, it is important to understand what risk factors you have and what you can do about them (4). Risk factors for heart disease include:

  • High blood pressure
  • High blood cholesterol (our simple at-home test kits can detect this)
  • Being overweight or obese
  • Having prediabetes or diabetes
  • Smoking
  • Sedentary lifestyle
  • Family history (may indicate a genetic risk factor)
  • Unhealthy diet
  • Older than 55 for females or older than 45 for males

Of course, it isn’t possible to change some of these risk factors, including age and family history. But simple lifestyle changes can be made to reduce other risk factors.

Get your blood pressure and cholesterol checked
Visit your healthcare professional to measure your blood pressure. It is simple, painless, and very quick. Or purchase a self-measured blood pressure monitor (SMBP) to easily monitor your blood pressure at home (3).

Get a blood test to check your cholesterol levels. This can be through your doctor or simply use one of our at-home heart health tests for an accurate analysis.

Follow a heart-healthy diet
Focus on consuming lots of nutrient-rich foods to obtain plenty of vitamins, fiber, and other nutrients (4). Include these in your diet:

  • Vegetables
  • Fruits
  • Whole grains
  • Fat-free or low-fat dairy products
  • Good protein sources including fish, lean meats, eggs, nuts, seeds, legumes
  • Oils and foods high in monounsaturated and polyunsaturated fats (e.g. olive oil, nuts, salmon, avocadoes, tofu)

And try to limit your intake of salt, saturated and trans fats, and sugar. This means less:

  • Added salt (use herbs and spices instead for additional flavoring)
  • Premade sauces, mixes, and instant pouches (they tend to have added salt)
  • Fatty meats (opt for leaner, lower-fat meats instead)
  • Full-fat dairy (switch for lower-fat options)
  • Foods with partially hydrogenated oils (trans fats), such as microwave popcorn, margarine, coffee creamers
  • Sugary foods – swap those sweetened drinks for some water!

Try to keep a healthy weight
Being overweight or obese significantly increases the risk of heart disease, as well as high blood pressure, type 2 diabetes, breathing problems, and certain cancers (4). Aim to keep a weight that is within the “healthy weight” body mass index (BMI) range of 18.5 to 24.9. To maintain a healthy weight, it is important to have good nutrition, control your calorie intake, and obtain adequate physical activity on a routine basis.

Manage your stress levels
Stress, particularly long-term, can contribute to increased blood pressure (4). In addition, for many people, the usual response to stress is to do something unhealthy, like overeat, smoke lots, or consume more alcohol (5).

Healthy ways to reduce and control your stress include:

  • Consulting a professional counselor
  • Meditation
  • Physical activity
  • Stress management programs
  • Relaxation techniques

Abstain from smoking
Smoking contributes to a multitude of health problems, including as a major contributor to heart disease.

The chemicals in cigarettes can cause the cells lining the blood vessels to swell and become inflamed, narrowing the blood vessels. This contributes to the formation of atherosclerotic plaques, which occur when fat and cholesterol build-up. These cigarette chemicals also cause the blood to thicken and increase the risk of blood clots forming (6).

The more you smoke and the longer you continue to smoke, the higher your risk of heart disease. Quitting smoking immediately reduces your risk of heart disease. Consider joining a support group if you are having trouble quitting smoking on your own.

Keep physically active
Being physically active every day has numerous health benefits, including maintaining a healthy weight, lowering “bad” LDL cholesterol and increasing “good” HDL cholesterol, reducing stress, and lowering blood pressure. All of these are important for a healthy heart.

Manage diabetes
Diabetes and heart disease share many of the same risk factors. In the United States, at least 68% of people over 65 years with diabetes die from heart disease (5). Monitoring and effectively controlling your blood sugar levels is very important for diabetic people to reduce the risk of heart complications as well as other diabetic complications.

Limit alcohol intake
There is evidence that moderate alcohol consumption is beneficial for heart health. However, drinking too much alcohol contributes to many health issues, including obesity, high triglycerides, high blood pressure, irregular heart rate, and cardiovascular disease (5).

Men should not consume more than two alcoholic drinks per day, while women should limit their consumption to one drink per day (5).

Get enough sleep
Good quality sleep is vital for optimal health. It is important for healthy brain function, maintaining a healthy hormone balance, a good immune system, and healing and repairing heart and blood vessels (4).

The American Academy of Sleep Medicine (AASM) recommends that adults should get 7-9 hours of sleep a day (7). Consistently less sleep can increase the risk of heart disease, obesity, high blood pressure, diabetes, and stroke (4).

Take medication as directed
If your doctor has prescribed medication to help control elevated cholesterol, high blood pressure, or diabetes, it is important that the medication is taken as directed (3).

1. Heart Disease Facts. Heart Disease. CDC (Reviewed Sept 2020)

2. Heart Disease in Canada. Government of Canada (Modified Feb 2017)
3. 7 Strategies to Live a Heart-Healthy Lifestyle. National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP). CDC. (Reviewed Feb 2021)  
4. Heart-Healthy Living. National Heart, Lung, and Blood Institute. NIH. 
5. Lifestyle Changes for Heart Attack Prevention. Heart Attack. American Heart Association. (Reviewed July 2015) 
6. Smoking and Cardiovascular Disease. CDC Fact Sheet. 
7. Sleep Education. AASM.