adrenaline , also known as epinephrine , is one of those multi-purpose substances that our body uses to regulate different body processes.

It is a hormone, since it travels through the blood to reach different areas of the body and fulfill its task in the most remote corners of it, but is also a neurotransmitter , which means that it acts as an intermediary in the communication between neurons that is established in the synaptic spaces.

Below you can read the main characteristics of adrenaline and the functions it performs in our brain and beyond.

Where’s the adrenaline?

Adrenaline is produced by our body, specifically in the adrenal glands which are located above the kidneys. However, it can also be synthesized in laboratories to create drugs administered in medical emergencies. The latter, by itself, serves to give us an idea of the importance for our organism of the existence of a substance such as adrenaline, which intervenes in several of the most basic survival processes.

Adrenaline: the substance of activation

It is true that adrenaline has many functions, but that does not mean that we cannot recognize a more or less clear pattern in the different effects it has on us. This pattern can be summarized as follows: adrenaline is the hormone and neurotransmitter of the situations in which we have to be alert and activated . In other words, adrenaline predisposes us to react quickly and prepares us to get the most out of our muscles when it is necessary to move with a certain speed, either because of the danger we are in or because we find ourselves in situations where we are offered the opportunity to win something if we are agile enough.

Adrenaline prepares us for situations in which we need to be especially active both physically and psychologically. That is why it can be said that adrenaline triggers survival mechanisms that are set in motion in emergency situations, such as those in which danger is perceived or one has to react quickly.

Different activation mechanisms

Adrenaline does not act globally by activating our organism, since there is no single “spring” that puts us in that state of alert. Instead, it goes to different parts of the body to produce different effects that, in their interaction with each other and with the rest of the vital functions, have as a consequence the activation .

These are the most important warning processes that adrenaline triggers when it is secreted in relatively high quantities:

1. Dilates pupils

Adrenaline makes the pupils dilate, so that more light enters and we are more aware of what is going on around us. This is a biological mechanism that for millions of years has helped us to adapt to our environment and to react quickly to possible dangers.

2. Dilates blood vessels

Thanks to the adrenaline, the blood vessels most related to the vital organs are widened, while those that are thinner and close to the outer layer of the skin are compressed (giving us a somewhat pale appearance), as they are not as important and in dangerous situations they could even break. The result is an increase in blood pressure , and a greater resistance to possible attacks or accidents.

3. Mobilizes glycogen

The release of adrenaline is related to the breakdown of glycogen, which is the energy reserved in the muscles and other parts of the body for those more physically demanding moments. The consequence of this is that the concentration of glucose in the blood ready to be burned (for example in case of imminent danger) increases .

4. Increases heart rate

It gets the heart rate to become faster so that we can cope with large efforts more easily . By pumping more blood, our muscles are better supplied with oxygen, so they can cope with greater efforts.

5. Stops the movement of the intestines

It slows down the movement of the intestines, since consumes energy that is not as necessary in times of alert . A way to ensure that the energy is concentrated in the muscles.

6. Increases the rate at which we breathe

Adrenaline increases the rate at which we breathe in and out, to better oxygenate the blood and perform more physically . This allows us to react more energetically to stimuli that indicate danger, even though we were in a state of rest a minute earlier.

7. Consolidates long-term memories

There are studies that suggest a role for adrenaline in making certain learnings more consolidated in emotional memory, so that they are easier to recover in the long term.

Physiological and psychological effects

As with all hormones and neurotransmitters, adrenaline cannot be said to have effects only on the “rational” dimension of our psyche, just as it does not have them exclusively on our more emotional side.

The functions it fulfils are both physiological (such as regulation of blood pressure or breathing rate and pupil dilation) and psychological (keeping us alert and more sensitive to any stimulus), as both domains overlap.

Excess adrenaline is also paid for

An excess of adrenaline is not free for our organism. Rising imbalances in the levels of this substance can lead to hypertension, headache, increased temperature and symptoms associated with anxiety disorders or chronic stress, such as nausea, trembling or sleep problems. In addition, adrenaline peaks can make vision more blurry , as they increase pressure in the eyes.

This is something we should take into account when assessing the quality of our lifestyle. Being very active all day can be more or less productive depending on the person and the context, but it is certainly not healthy. The body needs to rest and that is why we should pay attention to the signals our body sends us in the form of tiredness and sleep.

Bibliographic references:

  • Cahill L, Alkire MT (March 2003). “Epinephrine enhancement of human memory consolidation: interaction with arousal at encoding”. Neurobiology of Learning and Memory. 79 (2): pp. 194 – 198.
  • Martin, J.H. (1997). Neuroanatomy. Text and Atlas. Madrid: Prentice Hall.
  • Netter, F.H. (1999). Nervous System: Anatomy and Physiology. Madrid: Masson.
  • Paradisis, M.; Osborn, D. A. (2004). Adrenaline for prevention of morbidity and mortality in preterm infants with cardiovascular compromise. The Cochrane Database of Systematic Reviews (1): CD003958.
  • Soler, M. (Ed.). (2003). Evolution. The basis of Biology. Granada: Proyecto Sur de Ediciones.