Cortisol - what is it and what does it do
Published February 27, 2020
Your body is hard-wired to react to stress in ways meant to protect you against threats from predators and other aggressors. Such threats are rare today, but that doesn't mean that life is free of stress.
On the contrary, you undoubtedly face multiple demands each day, such as taking on a huge workload, paying the bills and taking care of your family. Your body treats these so-called minor hassles as threats. As a result you may feel as if you're constantly under attack. But you can fight back. You don't have to let stress control your life.
Understanding the natural stress response
When you encounter a perceived threat — such as a large dog barking at you during your morning walk — your hypothalamus, a tiny region at your brain's base, sets off an alarm system in your body. Through a combination of nerve and hormonal signals, this system prompts your adrenal glands, located atop your kidneys, to release a surge of hormones, including adrenaline and cortisol.
Adrenaline increases your heart rate, elevates your blood pressure and boosts energy supplies. Cortisol, the primary stress hormone, increases sugars (glucose) in the bloodstream, enhances your brain's use of glucose and increases the availability of substances that repair tissues.
Cortisol also curbs functions that would be nonessential or detrimental in a fight-or-flight situation. It alters immune system responses and suppresses the digestive system, the reproductive system and growth processes. This complex natural alarm system also communicates with the brain regions that control mood, motivation and fear.
When the natural stress response goes wild
The body's stress-response system is usually self-limiting. Once a perceived threat has passed, hormone levels return to normal. As adrenaline and cortisol levels drop, your heart rate and blood pressure return to baseline levels, and other systems resume their regular activities.
But when stressors are always present and you constantly feel under attack, that fight-or-flight reaction stays turned on.
The long-term activation of the stress-response system and the overexposure to cortisol and other stress hormones that follows can disrupt almost all your body's processes. This puts you at increased risk of many health problems, including:
- Digestive problems
- Heart disease
- Sleep problems
- Weight gain
- Memory and concentration impairment