Everything You Need to Know About the Stress Hormone
Cortisol plays an essential part in our body’s handling of stressful, threatening or dangerous situations. But chronically elevated levels of cortisol can compromise our health and well-being.
What is cortisol?
Cortisol is a steroid hormone, produced in the adrenal glands. Most cells in the body have cortisol receptors, so it can affect many different bodily functions. The brain – specifically the hypothalamus, which regulates the autonomic nervous system, and the pituitary gland – monitors the amount of cortisol in your blood. When levels are off, the brain sends a signal to the adrenal glands, which receive that information and adjust the amount of cortisol they make and release.
How does the body respond to stress?
As we evolved as humans, our bodies became hard-wired to protect themselves against threats. In today’s world, it’s unlikely that we’ll be caught unawares by a hungry saber-toothed tiger and need to make a run for it, but that doesn’t mean our modern lives are free of stress. And when push comes to shove, our bodies don’t draw a distinction between fighting off a ferocious predator and the daily stressors of paying bills, feeding the kids and hitting your work deadlines. Any feelings of stress or fear – whether from a real or perceived threat – cause the adrenal glands to release adrenaline, which raises your heart rate and blood pressure and increases energy stores, then cortisol. It controls mood, motivation and fear, but is best known as controlling your “fight-or-flight” response to high-stress situations. When your body is on high alert, it can shut down systems it deems unnecessary in the current situation, like the digestive, reproductive or immune systems, to conserve energy for the task at hand. When the threat passes, your body systems regulate and go back to normal.
But what if they don’t?
If you are under constant stress, the body’s fight-or-flight response stays turned on. That over-activation of the stress response and over-production of cortisol can lead to a whole host of unwanted symptoms, including anxiety, depression, headaches, heart disease, high blood pressure, digestive issues, thyroid problems, decreased bone density, difficulty sleeping and trouble focusing. High cortisol levels can also cause the breakdown of muscle tissue, and because cortisol is a powerful anti-inflammatory and inflammation is needed to heal muscle tissue, too much cortisol can delay muscle repair and reduce long-term strength adaptations. Cortisol also controls how your body metabolizes carbohydrates, fats and proteins and can therefore cause weight gain. So, if you’re in a training ‘rut,’ high stress levels could be the culprit.
Chronically high cortisol levels can also lead to Cushing syndrome, or hypercortisolism. Tell-tale symptoms include a fatty hump between the shoulders, a rounded “moon” face or pinkish-purple stretch marks on the skin.
How do cortisol levels vary naturally?
Our cortisol levels are generally higher in the morning when we wake up, then gradually fall throughout the day, in accordance with our Circadian rhythm. The pattern repeats daily, but if you work a night shift, this could be reversed, as the release of cortisol is linked to daily activity patterns. Small releases of cortisol in response to stressors do also have some positive effects, including a quick burst of energy, a feeling of alertness and a lowered sensitivity to pain.
How to know if your cortisol levels are too high or too low?
Off-kilter cortisol levels can have a variety of effects on your body, including fatigue, dizziness, weight gain, high blood pressure, muscle weakness, mood swings, lack of sex drive and irregular periods. If you think your cortisol levels are not optimal, see your doctor. Cortisol levels can be tested through blood, saliva and urine testing, and may require samples to be taken at several times during the day.