The effects of caffeine on physical and mental performance
For Phytocea by Léa Bathily, Dietitian
Physical performance is the subject of much research and inquiry regarding ways to optimize it. Today, several categories of nutritional products exist that aim to improve comfort and performance during exercise. Among these products, those rich in caffeine, such as energy drinks, have become widespread. What does science say about the effects of caffeine on physical performance? Is the combination of these two components safe for health? What are the limits to caffeine consumption?
What is caffeine?
Caffeine (or trimethylxanthine) is a molecule belonging to the methylxanthine family; it is found naturally in certain foods but can also be synthesized.
Although its name is similar to that of coffee, caffeine is a molecule naturally present in many other foods and plants (more than 60 plants contain caffeine). It is found in tea and yerba mate leaves, guarana seeds , kola nuts, and also in small quantities in cocoa. Furthermore, it has different names depending on its origin. For example, you have probably already heard of theine, which is simply the caffeine found in tea.
What are the physicochemical properties of caffeine?
One of caffeine's unique characteristics is that it is completely absorbed by our intestinal cells and then enters our bloodstream. This property is advantageous because a minimal amount of only 75 mg is sufficient to produce effects on our nervous system. Another important characteristic is caffeine's half-life. The half-life of a substance is the time it takes for half of it to become inactive. The average half-life of caffeine is 4 hours, but this obviously varies between individuals. To put it simply, this means that when we consume a substance (coffee, tea, etc.) containing a certain amount of caffeine, half of that initial amount will be metabolized by our body after an average of 4 hours.
What are the effects of caffeine on the body?
The functions of caffeine on the nervous system
Caffeine acts on various parts of our body, particularly the nervous system. Caffeine is considered a psychotropic drug because it stimulates the central nervous system, which is responsible for controlling sensory perception, movement, and the functioning of certain organs.
More specifically, it is well known that caffeine reduces fatigue and increases alertness. This characteristic is explained by caffeine's inhibitory effect on the sleep-wake cycle. This cycle is regulated by adenosine, a molecule that accumulates in the brain during wakefulness. Adenosine then binds to its specific receptors. At a certain concentration, this process promotes sleep. Caffeine has a biochemical structure similar to that of adenosine. In practical terms, this means that caffeine binds to adenosine receptors without replacing the reactions that would have triggered adenosine. Physiologically, caffeine blocks adenosine from binding to its receptors and therefore the resulting processes, such as falling asleep. Caffeine is said to be a competitive inhibitor because it prevents a reaction by competing with the molecules involved. At the same time, caffeine increases the concentration of excitatory hormones, adrenaline and dopamine. These hormones have the effect of increasing alertness and concentration in the nervous system.
What is the effect of caffeine on the cardiovascular system?
As we mentioned earlier, caffeine induces the release of adrenaline, and this phenomenon has consequences for the cardiovascular system. Indeed, adrenaline leads to:
-
A vasoconstrictive or vasodilatory action, that is to say the narrowing or widening of blood vessels;
-
Increased heart rate;
-
Increased blood pressure;
-
Increased blood flow to the muscles.
Normally, adrenaline is released in situations of stress and/or intense physical activity. This hormone allows us to react quickly in these kinds of situations. For example, in the case of stress in the event of a threat, adrenaline allows our body to act accordingly and prepare itself to flee (for instance, by increasing heart rate and improving blood flow to our muscles so they can function effectively).
It is not recommended to consume caffeine while engaging in physical activity. Indeed, the high concentration of adrenaline induced by caffeine, combined with that caused by physical activity, could have cardiovascular consequences.
What is the effect of caffeine on lipid metabolism?
Caffeine affects lipid metabolism by promoting lipolysis. In our bodies, lipids are stored in a specific tissue: adipose tissue. The cells that compose it are adipocytes, and their main role is to store lipids as triglycerides in a compartment called a lipid vacuole. To provide energy, triglycerides are broken down into fatty acids by enzymes; this is called lipolysis. The fatty acids are then released into the bloodstream to be used by cells in other tissues to produce energy through complex enzymatic reactions.
Furthermore, adrenaline also plays a role in lipolysis, as this hormone primarily serves to mobilize resources to cope with situations requiring energy. Adrenaline thus promotes the breakdown of triglycerides, which subsequently leads to the release of free fatty acids into the bloodstream, and so on. In addition, adrenaline also promotes energy production from glucose stored in the muscles and liver.
What is the relationship between caffeine and athletic performance?
Note that caffeine is not a miracle molecule, and its role in physical performance is not universally accepted within the scientific community. Nevertheless, the various mechanisms identified are thought to play a role in physical performance, as caffeine is believed to have an ergogenic effect. This means that this molecule could improve muscle work and overall muscle capacity. Several theories support this phenomenon.
Indeed, due to its effects on cognitive functions, caffeine may improve endurance by altering the central nervous system's perception of exertion. Furthermore, some studies have shown that intakes of 3 to 6 milligrams of caffeine per kilogram of body weight enhance endurance. Others have identified that a certain dose of caffeine improves physical performance during short, intense activities. Another theory focuses on caffeine's effect on lipolysis, which would allow muscles to access energy more quickly. These studies were conducted under various conditions that did not necessarily simulate real-life exercise situations. However, many of them agree on the role of caffeine in athletic activity.
What are the disadvantages of caffeine?
Beyond its nootropic effects, caffeine has drawbacks, and its effects vary depending on the individual, their genetic makeup, and their health status (the effects of caffeine are notably amplified in certain gastrointestinal conditions). Depending on your susceptibility to its effects, it is important to pay particular attention to the amount of caffeine consumed.
Among the disadvantages of caffeine consumption are:
-
The risk of degraded sleep quality (do not consume caffeine too late);
-
Disruptions in thermoregulation;
-
Changes in bowel movements;
-
During physical exercise, it constitutes a risk factor for cardiac events in predisposed individuals;
-
It can cause an increase in heart rate during exertion;
-
It can cause agitation and tremors;
-
The risk of inducing psycho-behavioral disturbances in some people: nervousness, irritability, anxiety or panic attacks.
These disturbances are more common in people who are sensitive to or unaccustomed to caffeine consumption and are often dose-dependent. For example, chronic use of high doses of caffeine (i.e., above 300 mg/day) is likely to exacerbate psycho-behavioral effects.
Therefore, one should pay attention to one's sensitivity to caffeine before consuming it.
What are the recommendations of the health authorities?
The European Food Authority recommends a maximum caffeine intake of 400mg per day to avoid side effects.
In addition, ANSES (the French Agency for Food, Environmental and Occupational Health & Safety) warns of the effects of caffeine on the body during prolonged physical exercise. Caffeine interferes with the proper functioning of thermoregulation during exertion, and the sweating process is therefore impaired, preventing the body from cooling down effectively. This phenomenon can lead to hyperthermia.
Caffeine should therefore be consumed separately from physical exercise. It is thus preferable to avoid consuming energy drinks high in caffeine during exercise.
To give you an idea, here are the amounts of caffeine present in everyday drinks:
-
One cup of filtered coffee: 90 mg of caffeine
-
A short coffee/espresso: 80 mg of caffeine
-
An energy drink (250ml): 80 mg of caffeine
-
A cup of black tea: 50 mg of caffeine
-
A cola-based drink (330ml): 40 mg of caffeine
-
One bar of dark chocolate (50g): 30mg of caffeine
Phytocea has the right food supplement for physical and mental performance.
Caffeine consumption is not recommended during exercise, but it is very useful for improving cognitive performance. Currently, the French Agency for Food, Environmental and Occupational Health & Safety (ANSES) has validated the following health claim: "Caffeine contributes to increased alertness." This health claim applies to a minimum consumption of 75 mg.
Therefore, for optimized effects on concentration, we formulated Reboost , a dietary supplement rich in caffeine derived from guarana seeds. This nootropic helps increase alertness, reduce fatigue and mental exhaustion, and improve mental performance.
If you're looking for a dietary supplement to support your physical activity, we recommend ReCharge , a magnesium-rich supplement. Magnesium loss and specific magnesium requirements increase during exercise, impacting physical performance. ReCharge is therefore the ideal supplement to minimize discomfort such as cramps during sports activities. This supplement is formulated with high-performance, next-generation magnesium forms: magnesium glycerophosphate and magnesium pidolate. Combined with vitamin B6 , the magnesium in ReCharge is truly effective in restoring normal magnesium levels. It thus helps improve athletic recovery by addressing trace element deficiencies after exercise.
If you would like to learn more about the link between the role of magnesium in physical performance, we invite you to read the following article: " Magnesium and physical performance, what is the link between the two? ".
=== content-split ===
7883973853398
=== content-split ===
Sources
EFSA: Risk assessment explained by EFSA, caffeine
ANSES: Caffeine: a substance that's not so harmless
ANSES: Dietary supplements for athletes
