An adrenaline rush---also called the fight-or-flight response---is caused by a hormone release from the adrenal gland. In healthy people, the hormone release consists of 80 percent epinephrine (also called adrenaline) and 20 percent norepinephrine. It is the body's natural coping reaction for activities or environmental situations that are exhilarating, stressful or physically demanding.
When epinephrine and norepinephrine are released into the body, your body's airways and large blood vessels dilate to funnel larger amounts of oxygen, glucose and blood to the respiratory system, muscles and brain. This hormone release also increases your heart rate and blood-sugar levels, improving the body's performance for the short term. Those experiencing adrenaline rushes typically feel temporarily stronger, faster and more tolerant of pain.
While the stress response is an important part of managing fear and excitement, an adrenaline rush can produce feelings of anxiety, tension and panic---also part of the body's fight-or-flight response. That's why it's important to allow your body to work off the hormones released during an adrenaline rush. When you encounter a high-stress situation that does not include physical activity, you may be faced with lingering hormones that cause jittery, anxious or sleepless feelings. After dealing with high amounts of adrenaline-producing stress, take a walk, go for a jog or engage in deep-breathing exercises until the hormones leave your system.
The duration of an adrenaline rush varies by person and situation. Typically, the epinephrine and norepinephrine triggered during fight-or-flight are metabolized as the body deals with the physically demanding situation. When the threat is resolved, the body begins to return to its normal state. However, as mentioned above, you may need to exercise in order to metabolize remaining hormones and decrease lingering feelings of panic.
While adrenaline rushes are normal, some people may experience harmless side effects during the hormone release. These effects may include severe sweating, trembling in the extremities, knots in the stomach or an inability to speak, which typically resolve after the body returns to a normal metabolic state.
See your health practitioner if you experience adrenaline rushes that occur frequently or last for long periods. Prolonged releases of stress hormones may have a negative effect on the body and may be caused by an underlying medical condition.