Adrenaline Rush, Definition, Meaning, What Is Adrenaline?


Adrenaline is a naturally occurring hormone in the body. During an adrenaline rush, the hormone, which is also known as epinephrine, is released in response to situations which may be exciting, dangerous or threatening.


An adrenaline rush can be important in a "fight or flight" situation as the effects that the hormone has on the body temporarily improve physical performance.


Epinephrine has many effects on the body including increased oxygen and glucose to the brain and muscles, dilated pupils, increased heart rate and the elevation of blood sugar levels.


There are some people who have become addicted to having an adrenaline rush. If the hormone is released often enough, the body begins to memorize the associated feelings which can ultimately lead to a serious addiction which can be just as difficult to quit as any other addictive drug.

Amazing Fact

Certain people have experienced "super" strength during an adrenaline rush in emergency situations and have been able to lift cars, helicopters and other heavy objects that humans cannot lift under normal circumstances.

Adrenaline Definition

Sense 1


A catecholamine secreted by the adrenal medulla in response to stress (trade name Adrenalin); stimulates autonomic nerve action

Classified under:

Nouns denoting body parts


Adrenalin; adrenaline; epinephrin; epinephrine

Hypernyms ("adrenaline" is a kind of...):

pressor vasoconstrictive; vasoconstrictor (any agent that causes a narrowing of an opening of a blood vessel: cold or stress or nicotine or epinephrine or norepinephrine or angiotensin or vasopressin or certain drugs; maintains or increases blood pressure)

endocrine; hormone; internal secretion (the secretion of an endocrine gland that is transmitted by the blood to the tissue on which it has a specific effect)

neurotransmitter (transmits nerve impulses across a synapse)

catecholamine (any of a group of chemicals including epinephrine and norepinephrine that are produced in the medulla of the adrenal gland)

The Adrenal Glands

The adrenal glands are found directly above the kidneys in the human body, and are roughly 3 inches (7.62 cm) in length. Adrenaline is one of several hormones produced by these glands. Along with norepinephrine and dopamine, it is a catecholamine, which is a group of hormones released in response to stress. These three hormones react with various body tissues, preparing the body to react physically to the stress causing situation.

The function of the adrenal gland and the release of adrenaline helps a person to cope with stressful, live threatening or emergency situations. A boost of glucose and oxygen are sent to the brain and muscles while other bodily functions are suppressed.

Adrenaline Rush Meaning and Facts

An adrenaline rush can happen in a variety of situations, such as being chased by a bear in the woods or taking a biology final. An adrenaline rush is the body's natural reaction to a threat. It is a physiological process that prepares the body for battle or escape, often called the "fight or flight" reaction. It's what helped early humans survive the dangers in their environment. Though we rarely find ourselves in situations where we have to ward off a mountain lion or run from a herd of charging buffalo, the adrenaline rush still happens in modern times of stress.


Adrenaline is another name for epinephrine, the substance that is secreted by the adrenal gland. The adrenal gland is located right above the kidney.

Adrenaline is a natural stimulant produced by the human body. Adrenaline is produced by the adrenal glands in your body when stress, danger, excitement or any unexpected changes in the environment occur. This sensation is often called an adrenaline rush. When adrenaline is in your bloodstream, it quickly prepares your body for action in these stressful, emergency situations. It causes increased heart rate, sweating, and increased metabolism.

Although adrenaline is usually associated with stress and emergencies, athletes who are under pressure to excel, including competitive inline skaters, may also experience adrenaline rushes. These athletic adrenaline rushes can provide a skater with a positive boost that may briefly improve or extend his or her physical performance capabilities. Some athletes may even become adrenaline junkies who constantly seek unusual adventures to trigger an adrenaline rush. In inline skating sports, these rush seekers usually migrate toward the aggressive and gravity-based roller sports.

Physical Effects

When adrenaline is released into the blood system, it goes to work to make some changes in the way the body is functioning. The heart begins to pump harder, and blood pressure goes up. Airways in the lungs open up while blood vessels in the skin and intestines narrow. This causes blood to flow away from these organs and flow into major muscle groups. The body is preparing the muscles so that they may fight or have the energy to run away.

Rational Thinking

The fight-or-flight response brought on by an adrenaline rush is not easily controlled by your rational mind. You may be able to logically understand that taking a biology test cannot kill you or physically harm you. However, the response from your adrenal gland bypasses any form of rational thought.

Chronic Stress

Some complications can occur with excess adrenaline. People who experience chronic stress and anxiety disorders can incorrectly perceive a threat from their environment. They may worry about something simple like being late to a meeting or something complicated like a relationship with a spouse. Either way, the body doesn't differentiate the threat of bodily harm from the threat of stress from emotions. It reacts in the same way, causing symptoms of panic and anxiety. This can become a source of severe distress for some people.

Thrill Seekers

An adrenaline rush is not always a negative experience. Many people relate an adrenaline rush to extreme sports and adventures. Someone might say that they love roller coasters because of the adrenaline rush. The excitement of these kinds of activities results in the same bodily response as threatening situations. When a person knows he is not in harm, the fluttery feeling in his chest and accelerated heartbeat can be fun and exciting.

Alternative Names

Also Known As: Epinephrine

Alternate Spellings: Adrenalin

What Is Adrenaline?

Adrenaline is a hormone produced by the adrenal glands during high stress or exciting situations. This powerful hormone is part of the human body's acute stress response system, also called the "fight or flight" response. It works by stimulating the heart rate, contracting blood vessels, and dilating air passages, all of which work to increase blood flow to the muscles and oxygen to the lungs. Additionally, it is used as a medical treatment for some potentially life-threatening conditions including anaphylactic shock. In the US, the medical community largely refers to this hormone as epinephrine, although the two terms may be used interchangeably.

The Fight or Flight Response

The term "fight or flight" is often used to characterize the body's reaction to very stressful situations. It is a created evolving adaptation that allows the body to react to danger quickly. Dilated air passages, for example, allow the body to get more oxygen into the lungs quickly, increasing physical performance for short bursts of time. The blood vessels contract in most of the body, which redirects the blood toward the heart, lungs, and major muscle groups to help fuel the reaction.

When a person encounters a potentially dangerous situation, the hypothalamus in the brain signals the adrenal glands to release adrenaline and other hormones directly into the bloodstream. The body's systems react to these hormones within seconds, giving the person a nearly instant physical boost. Strength and speed both increase, while the body's ability to feel pain decreases. This hormonal surge is often referred to as an "adrenaline rush."

Side Effects

In addition to a noticeable increase in strength and performance, this hormone typically causes heightened awareness and increased respiration. The person may also feel lightheaded, dizzy, and experience changes in vision. These effects can last up to an hour, depending on the situation.

When there is stress but no actual danger, a person can be left feeling restless and irritable. This is partly because adrenaline causes the body to release glucose, raising blood sugar, and giving the body energy that has no outlet. Many people find it beneficial to "work off" the adrenaline rush after a particularly stressful situation. In the modern world, high-stress situations often arise that involve little physical activity. Exercise can use up this extra energy.

Though adrenaline can play a key role in the body's survival, it can also cause detrimental effects over time. Prolonged and heightened levels of the hormone can put enormous pressure on the heart muscle and can, in some cases, cause heart failure. Additionally, it may cause the hippocampus to shrink. High levels of adrenaline in the blood can lead to insomnia and jittery nerves, and are often an indicator of chronic stress.

Medical Uses

First synthesized in 1904, adrenaline is a common treatment for anaphylaxis, also known as anaphylactic shock. It can be quickly administered to people showing signs of severe allergic reactions, and some people with known severe allergies carry epinephrine auto-injectors in case of an emergency. For these individuals, dosage should be assigned by a licensed medical professional in advance, and instructions should be given on how and where it should be administered.

Adrenaline is also one of the main drugs used to treat low cardiac output — the amount of blood the heart pumps — and cardiac arrest. It can stimulate the muscle and increases the person's heart rate. In addition, by concentrating blood in the vital organs, including the heart, lungs, and brain, it helps increase the chances that the person will recover more fully.

What Happens During an Adrenaline Rush?

Adrenaline, or epinephrine, is a stress hormone secreted from the adrenal glands on the kidneys. It plays a major role in preparing the body for a fight-or-flight reaction in threatening environments. An adrenaline rush is a sudden increase in the secretion of adrenaline from the adrenal glands. This happens when the brain communicates to the glands that there will be a need for a fight-or-flight response. The cause of an adrenaline rush need not be an actual physical threat but can also be an imagined threat, strenuous exercise, heart failure, chronic stress, anxiety or a disorder of the brain or adrenal glands.

Adrenaline Rush

When you perceive something as threatening or exciting, the hypothalamus in the brain signals to the adrenal glands that it's time to produce adrenaline and other stress hormones. The adrenal glands produce adrenaline by transforming the amino acid tyrosine into dopamine. Oxygenation of dopamine yields noradrenaline, which is then converted into adrenaline. Adrenaline binds to receptors on the heart, arteries, pancreas, liver, muscles and fatty tissue. By binding to receptors on the heart and arteries, adrenaline increases heart rate and respiration, and by binding to receptors on the pancreas, liver, muscles and fatty tissue, it inhibits the production of insulin and stimulates the synthesis of sugar and fat, which the body can use as a fuel in fight-or-flight situations.

Detrimental Effects

An adrenaline rush can have detrimental effects on health. In people with heart disease, it can cause a weakening of the heart muscle, heart failure or a heart attack. It can also affect the brain in negative ways. Continuous heightened levels of stress hormones can lead to a shrinkage of the hippocampus, the brain's main memory center, according to a research team in the January 2008 issue of PNAS. Stress hormone stimulates the production of IL-1 beta, a cytokine, or signaling molecule, that creates inflammation in the hippocampus and prevents the formation of new neurons. IL-1 beta also binds to sites in the hypothalamus, pituitary and the hippocampus, the researchers found.

Beneficial Effects

While hyperactivity in the adrenal gland can have detrimental effects on health, mildly increased levels of stress hormones can have positive effects on the blood content of leptin, a protein that is produced in the body's white fatty tissue and that accelerates the growth of cancer cells, according to a research team in the July 2010 issue of Cell. While the blood content of leptin normally is directly proportional to the amount of fatty tissue in the body, stress hormones may play a role in regulating how much leptin the fatty cells produce. The less they produce, the slower cancer cells will grow, the researchers say.

Stress Hormones and Memory

While adrenal glands constitute a major site for adrenaline synthesis, adrenergic neurons in the brain stem also produce adrenaline. These neurons contain the enzyme PNMT, which is required for a gland or neuron to convert noradrenaline into adrenaline. Stressful situations accelerate the activity of adrenergic and noradrenergic neurons. This can have a profound, negative effect on memory, according to a research team in the October 2008 Journal of Neuroscience. When stress chemicals function as neurotransmitters, they affect the storage of memories by activating the amygdala, a center of the brain involved in the processing and storage of negative emotions. Normally, people remember things better if they are replayed many times in the mind, but a single emotionally significant event may suffice for neurons to generate long-lasting networks.


Intermittent adrenaline rushes occurring for natural reasons do not require treatment. If chronic stress, anxiety or panic disorder triggers an excessive secretion of adrenaline, anti-anxiety medications, such as selective serotonin reuptake inhibitors, can alleviate symptoms by blocking the trigger. Beta-blockers, which bind to receptors on the heart, are commonly used to prevent a failing heart from going into overdrive from an excessive secretion of stress hormones. According to a report published in the February 2007 issue of Nature Medicine, another treatment for heart patients still under investigation consists in blocking adrenal gland GRK2, an enzyme that regulates adrenaline secretion.

5 Symptoms of an Adrenaline Rush

An adrenaline rush is an extremely intense feeling. Adrenaline is a natural hormone that is produced by the body and secreted throughout the body when you undergo some type of traumatic experience. For instance, if you are attacked by a dog or you get into a fist fight, you will notice an energetic feeling that gives you the power and strength to either escape or to attack. Because of this, an adrenaline rush can be intense and can be used in order to help you out. There are a number of different symptoms that you will probably experience if you undergo an adrenaline rush. Here are just a few of the symptoms of adrenaline:

1. Noticeable Increase in Your Strength

People who undergo an adrenaline rush during a major emergency have been known to do some crazy things. Some have lifted cars off the bodies of children. If you undergo an adrenaline rush, it's likely that you will have greater strength than when you do not have adrenaline on your side. If you are in the gym and you get an adrenaline rush, you may be able to life more weight than you ever could before. An adrenaline rush gives you a great deal of strength throughout your body.

2. No Feelings of Pain

An adrenaline rush can also be used to protect your body. If you've ever played a sport and injured yourself, there's a good chance that, initially, you didn't feel much pain. Even if you broke a bone, your body helps protect you from the pain by using an adrenaline rush. Once the adrenaline wears off, you'll be able to feel the pain again, but for the time being, the adrenaline will stop the pain.

3. Heightened Senses

From your vision to your touch, your senses will be dramatically heightened when you are undergoing an adrenaline rush.

4. Sudden Boost of Energy

Again, if you have ever played sports, you're usually more likely to be super pumped up when the game or match first starts. This is because an adrenaline rush will give you a large amount of energy as the body releases glucose and sugar directly into your bloodstream.

5. Increased Breathing

Because everything happens so fast during an adrenaline rush, your breathing and your heart rate will jump suddenly. Your blood pressure will also go up, and you may even start to sweat to prevent your muscles from getting overworked during an adrenaline rush.

Stopping an Adrenaline Rush

Typically, you body releases adrenaline only when you need it. However, if you are suffering from an extreme adrenaline rush, it's important that you try to calm yourself down. Monitor your breathing and look to take long, deep breaths to slow your heart rate and blood pressure down. Sit down and try to focus on what's happening as well. The trick is not to panic and to let the adrenaline rush wear off by relaxing. Once the adrenaline rush subsides, you can resume your normal activities.
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