Updated: Mar 30
By Raphael Gabiazon
It is commonly known that caffeine is primarily used to help people with their daily tasks to feel more awake, alert, and reduce their fatigue. This may be why most people in the world consume this psychoactive drug – a substance that alters the functioning of the brain and impacts one's mood, consciousness, thoughts, emotions, or actions (1, 2). Many food items we consume are prevalent in caffeine like in coffee, tea, chocolate, and energy drinks. Although the benefits of caffeine are well-known, the specific mechanisms for how it exerts its effects are not widely understood. This article will discuss the research behind caffeine and examine how it functions in the body to boost energy and improve focus.
The main reason most people consume caffeine is to increase their energy levels. This effect is a characteristic of a stimulant – a group of substances that can increase activity in the brain and nervous system (3). To fully understand the mechanisms of caffeine, it is important to first provide some background information. Throughout the day, a naturally occurring chemical in the body called adenosine builds up in the brain as a byproduct of metabolism (4). Adenosine plays a role in regulating sleep and primarily interacts with receptors which are special protein molecules that are located on the surface of cells and play a crucial role in the way that cells communicate with each other (5, 6). High levels of adenosine in the body have been reported to increase feelings of tiredness but are significantly reduced upon sleeping (7).
It appears that if the levels of adenosine are lower, it would decrease feelings of tiredness and sleepiness which can make one feel more awake. Although caffeine does not directly reduce the levels of adenosine, it works by impacting its receptors in the brain. Namely, it works by easily passing the barrier that separates the blood from the brain, so it can reach these adenosine receptors (8). Once it reaches the brain, caffeine prevents adenosine from attaching to its receptors (8). Specifically, caffeine blocks the action of a certain subtype of adenosine receptor called A2a, which results in the wakefulness effects of caffeine (9, 10). While there are more processes involved, caffeine's main mechanism of action on adenosine receptors in the brain is the primary factor behind the feeling of enhanced energy.
Another significant benefit of caffeine is its ability to improve focus. Research has shown that caffeine can enhance attention and concentration, which can allow for improved productivity and efficiency. For example, in one study by Zabelina & Silvia (11), 80 participants were administered either a 200 mg caffeine pill, equivalent to 12 oz of strong coffee, or a placebo pill 20 minutes prior to performing the Compound Remote Associates test (12) – which measures problem-solving and focused attention (13) – and other neuropsychological tasks.
They found that those who consumed caffeine performed better on the Compound Remote Associates test which meant that there was an improvement in the participant's ability to solve problems and indicated an enhancement in focus. The greater focus is believed to be due to caffeine's ability to boost dopamine - a chemical in the brain that primarily helps regulate movement, emotion, motivation, and feelings of pleasure (14). Contrary to this belief, research has shown that caffeine does not increase the amount of dopamine in the brain, but rather increases the availability of certain dopamine receptors in the brain (15). The increase in these receptors was associated with higher alertness – which is the state of being awake, aware, attentive, and prepared to act or react (15, 16). From these findings, it is likely that caffeine could improve focus and attention, as shown by increased alertness, through its effect on specific dopamine receptors.
Another reason that may explain the effects of caffeine on focus relates to catecholamines which are active molecules in the body that play important roles in maintaining balance through the nervous system and are made up of dopamine, norepinephrine (also known as noradrenaline), and epinephrine (also known as adrenaline) (17). These substances, in particular noradrenaline, are thought to assist with maintaining attention (18). One study found that there was an increase in adrenaline and noradrenaline in participants after having ingested coffee (19). Taken together, these findings suggest that caffeine consumption may improve focus through its impacts on specific dopamine receptors through elevating catecholamine levels.
In conclusion, extensive research supports the energy-enhancing effects of caffeine. This is mainly due to its classification as a stimulant, which works by blocking adenosine receptors in the brain to reduce feelings of fatigue. The benefits of caffeine can be observed in improved focus which could have implications for one’s productivity and efficiency. It is likely that this effect may be due to greater increases in certain dopamine receptors and catecholamine levels which can affect alertness and attention, respectively, which seem to be necessary for the ability to enhance focus. Whether it's combating tiredness or boosting work performance, caffeine can be a valuable tool to aid in these endeavors.
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