What Is Cortisol?

Cortisol is a naturally produced stress hormone. When you feel fear or danger, a section of your brain called the hypothalamus activates your "fight or flight" response. It calls the adrenal glands into action. The adrenal glands respond by releasing a wave of stress hormones.

The main stress hormone is cortisol. Its job is to streamline your body's workload so you can concentrate on the immediate threat. Another of the hormones is adrenaline, which tells your heart to beat faster. It also boosts your blood pressure and gives you increased energy.

Cortisol inhibits insulin effectiveness which makes your blood sugar (glucose) levels rise. It raises circulating glucose to the brain providing improved alertness. It also enhances your body's ability to repair tissues. Nonessential functions like growth and development are slowed down. Your reproductive system, digestive system, and immune system responses are also suppressed.

Part 3 of 5: Abnormal Levels

What Can Cause Abnormal Cortisol Levels?

Cortisol levels rise and fall naturally throughout the day. Absent a threat, your cortisol level is highest when you wake up in the morning and lowest when you're ready for sleep. Children tend to have less cortisol than adults do. Aside from stress, quite a few things can affect your cortisol levels, including:

Did You Know?The stress response is a temporary state. Once fear or danger passes, stress hormone levels drop and all systems return to their previous state.

• exercise
• lack of sleep
• shift work
• temperature
• alcohol and caffeine
• infection and trauma
• oral contraceptives and pregnancy
• certain medications, including steroids
• obesity
• disease

If your cortisol levels are abnormally high for a long time, it can cause a rare disorder called Cushing's syndrome. Treatment for Cushing's syndrome may include a cortisol blocker. A rare cause of high cortisol is an ACTH-producing tumor outside the pituitary gland. Adrenal gland problems can also cause high cortisol levels.

According to the Mayo Clinic, overexposure to stress hormones, including cortisol, can cause trouble within almost all your body's processes, increasing your risk of weight gain, sleep problems, and anxiety.

Part 4 of 5: Truth to Claims?