Chemical Changes That Occur during Stress

When you find yourself in a situation that your body perceives as stressful, a number of chemical reactions occur that push certain body systems into higher gear by shutting down or cutting off energy to others.

1. Stress affects the cardiovascular system. The first to be affected is the cardiovascular system. In the presence of danger, much of the blood in your outer extremities is shunted to organs that need more oxygen, such as the brain (the decision maker), the heart, and your other vital organs, such as the lungs and the liver. The constricting of the blood supply to your hands, arms, feet, and legs has another role—it decreases your blood loss should you be injured. Your body also increases its production of endorphins and other pain-reducing chemicals so that you won’t feel the injury as keenly as you normally would. When these changes happen, your blood pressure rises, your pulse races, and your heart must beat faster and harder to handle the strain. Adrenaline causes glucose and fat to be released from your tissues to give your body a much-needed energy surge in case you must fight or flee.
2. Some systems shut down. This enormous surge of energy comes at a price, however. Certain other bodily systems must be shut down somewhat in order to compensate. Your reproductive system, which is normally very energy intensive, is suspended so that its energies can be directed elsewhere. In the short term, this isn’t a bad thing, since you would never think about fighting off the cave bear and making love to your mate at the same time. But you can see how living in a constant state of stress would erode your libido over the long term.
3. How cortisol affects the body. Another chemical downside following the release of stress hormones is that cortisol accumulates in your body. As the adrenaline rush that released fat and glucose as an energy source subsides, the stress hormone cortisol becomes active, causing insulin to be released to stimulate your appetite so that you can replenish your fat stores. Since most of us don’t reach for an apple or a piece of swordfish when we are ravenous, this usually leads to craving a quick carbohydrate snack such as candy, pizza, cookies, ice cream, or high-carbohydrate fast foods. Unfortunately, living with a high level of daily stress causes the body to produce a consistently high level of cortisol, leading to overeating and weight gain, especially in the all-important abdominal area in men.
   
4. The immune system is weakened. One of the more serious effects of stress is the redirecting of energy away from the immune system. A tremendous amount of energy is necessary to operate the complex cells, hormones, and organs that make up this system. Fifteen minutes of danger and a return to normal isn’t going to compromise your immune system, but living with constant stress will surely make you more susceptible to illness.