How your body responds to stress.

Your body's central nervous, endocrine, immune, and cardiovascular systems are involved in responding to stress.

The physical responses can vary: Short-term responses can cause a racing heart, sweaty palms, and a pounding head. Long-term responses can cause back pain, high blood pressure, sleeplessness, and an inability to make decisions. Constant stress floods the body with stress hormones, which can increase the risk of serious health problems.

The hormone that initiates the body's response to stress, CRF, is found throughout the brain. Drugs of abuse also stimulate release of CRF. See the diagram to the right for how this works.

The Stress Hormone Cycle and Drugs

Under stress, the brain releases CRF, a hormone, into the bloodstream. Some drugs of abuse also stimulate the release of CRF. Through blood vessels, CRF travels to the pituitary gland.

Here CRF causes the release of ACTH, another hormone. ACTH travels to the adrenal glands and triggers the release of still more hormones, the most important of which is cortisol.

Cortisol helps you cope with stress. If stress is mild, cortisol prevents further release of CRF and ACTH. If stress is intense, the cycle continues.

[ILLUSTRATION OMITTED]