Caffeine, the intimate enemy
Sport and caffeine have a sulphurous love affair. After being considered a doping product and then removed from the Prohibited List, this familiar substance is once again making its place in WADA's monitoring program this year. Here is what you need to know.
Divine nectar, evil drink
The long history of the origins of coffee resonates surprisingly with recent reports that caffeine has with sport. The mythology of this drink is that it was an Ethiopian shepherd, responding to the name of Kaldi, who noticed the sudden gain in liveliness of his goats after they had grazed near coffee trees. Legend has it that this same shepherd was seduced by the aromas emanating from the burning of the branches of this shrub. Genetic studies now prove that coffee is originally from Ethiopia and that its local consumption probably dates back to prehistoric times. Its stimulating virtues are at the origin of its legend.
From the XNUMXth century, coffee went back to the Middle East through Yemen, via the Sufis, who appreciated its effects on the clarity of mind of those who consumed it. From the XNUMXth century, the Ethiopians began to roast coffee in embers in addition to grinding it into porridge used in pharmacy, like cocoa among the Aztecs. Coffee or K'hawah quickly became a real religion in the countries bordering the Red Sea. It then spread to all of Persia and then to Turkey. Very quickly, we wondered about the effects of coffee. At the beginning of the XNUMXth century, while attempts were made to find out whether this ink-black drink conformed to the Koran - the latter forbidding all forms of intoxication and all consumption of charcoal - an opponent of coffee claimed that it had the same intoxicating power as wine. The experts in Holy Scriptures remained skeptical and preferred to beat the opponent who obviously knew a little too much about the effects of wine! It was not long before doctors recognized the powerful effects of coffee, which was banned for a short time before its popularity overwhelmed any prohibition and forced the Sultan of Cairo to authorize the drink.
Same story in Europe, where the coffee craze spread rapidly from the 50th century. Pope Clement VII was even asked to prohibit the trade in this drink "of infidels", but the latter, after having dipped his lips in a small cup, judged that it would be a pity that the Christian world deprived itself of it. such a pleasure and decided, on the contrary, to baptize the coffee which then gained the whole world. Cafes quickly become places of freedom where liberal ideas are expressed and where revolutions are born, reinforcing its sulphurous image. Throughout its rapid conquest of manners, coffee has always been viewed in an ambiguous manner, between seduction for its stimulating virtues and repulsion for its addictive quirks and some of its deleterious effects on health. Balzac, known to drink up to XNUMX cups of coffee a day in order to bring down his Herculean labor, died of caffeism, a coffee overdose. Drink for fools for some, divine nectar for others, coffee quickly became the drink of poets, writers, intellectuals… but also sportsmen.
Coffee is divided into two large families: robusta, common and with a more bitter taste, and arabica, whose slow maturation gives it more subtle aromas. Caffeine is however present in many other plants, such as tea, chocolate or guarana.
To summarize :
- Coffee and caffeine have been consumed since the dawn of time and their psychotropic effects have been known since prehistoric times.
- The history of coffee and caffeine constantly oscillates between adoration, for their action on drowsiness, concentration and liveliness, and rejection, for their dangerousness and their propensity to make you "addicted".
Caffeine belongs to the large family of alkaloids, where we also find nicotine, morphine or cocaine.
To summarize :
- Caffeine, by its proximity to adenosine, crosses the blood-brain barrier that separates the blood circulation of the brain and that of the rest of the body.
- Caffeine inhibits adenosine, which is responsible for, among other things, the body's slow-wave sleep (physical repair), and increases the secretion of adrenaline and dopamine.
- Caffeine reduces the feeling of fatigue (and not the fatigue itself), acts as a psychostimulant and increases concentration while having a limited analgesic effect
- Caffeine, metabolized by the liver, also increases lipolysis (transformation of fat into glycogen and fatty acids), the amount of urine (diuretic effect) and acts, weakly, on the smooth muscles of the bronchi (treatment against asthma ).
Fast action
Caffeine was discovered in 1819 by the German chemist Friedlieb Ferdinand Runge who called it so ("Kaffein") because of its presence in significant quantities in coffee. But we find caffeine, or methyltheobromine, in many foods, such as chocolate, or in many leaves, such as mate, tea or guarana. It is also used today in the composition of famous sodas or in those of energy drinks. Its psychotropic power, as we have seen, has been known since the dawn of time. In nature, caffeine serves as a natural insecticide, paralyzing or even killing insects that can feed on plants that contain it.
Caffeine belongs to the large family of alkaloids, alongside morphine, cocaine and even nicotine. In pure form, these molecules are highly toxic and cause addictive effects. Caffeine is no exception to this rule. Caffeine acts on the receptors for adenosine, a neural neurotransmitter, the main maker of slow-wave sleep, the one in charge of repairing physical fatigue. By “preventing” the action of adenosine, caffeine thus acts directly on drowsiness. This results in increased alertness and improved concentration. Contrary to many popular beliefs, caffeine is quickly absorbed by the digestive tract. Numerous studies show that the effects start 15 minutes after absorption and that the peak concentration in the blood is reached after an hour. After 24 hours, all traces of caffeine in the body disappear.
Its proximity to adenosine allows it to cross the blood-brain barrier, making it possible for it to access neurons. By "taking the place" of adenosine, caffeine has a disinhibitory action on brain activity, causing the production of adrenaline and dopamine. If these substances can have interesting virtues in the sports context (increase of blood supply to the muscle or increased resistance to pain), they also have deleterious effects, such as increased heart rate and blood pressure.
Metabolized by the liver, caffeine is transformed into three isomers with different properties. The vast majority is metabolized to paraxanthin, the effect of which is to increase lipolysis, the mechanism which “breaks” fats and transforms them into fatty acids and glycerol. This property explains the preponderant place taken by caffeine in diets. It is still important to keep in mind that this action does not increase according to the dose of caffeine ingested: from a reduced amount (2 to 6 mg / kg / day), effects on lipolysis no longer increase. Just over 10% of an ingested dose of caffeine is also metabolized into theobromine, which is known to dilate blood vessels and increase urine volume, hence the diuretic property of caffeine. Finally, less than 5% of caffeine is transformed into tehophylline, whose action on the smooth muscles of the bronchi is proven. At doses much higher than that induced by normal caffeine consumption, theophylline is used to treat asthma.
Precarious balance
As we have seen, caffeine, in moderate doses, ie a maximum of half a dozen cups of coffee or three liters of tea per day, increases the capacity for mental and physical work. Various studies show a significant difference in performance between athletes who have consumed caffeine and other non-consumers, mainly in endurance and distance events (cycling, running, etc.). However, these properties are quickly counterbalanced by the side effects of caffeine, largely incompatible with sports activity and, above all, with obtaining results. One thinks of its diuretic effect, coupled with the fact that caffeine causes the relaxation of the internal anal sphincter and therefore diarrhea, for example. Hyperglycemia, due to hypolysis, increased heart rate, drowsiness or anxiety are all effects contrary to effective sports practice which appear even within the framework of reasonable absorption. In addition, it should be borne in mind that adenosine stimulates slow wave sleep, that in charge of muscle repair and physical fatigue ... at least useful for an athlete! Caffeine consumption therefore directly influences the ability to recover quickly.
Beyond the maximum recommended doses, the negative effects become dangerous. Anxiety, excitement, insomnia, flushing of the face, digestive disturbances, involuntary contractions, irritability, cardiac arrhythmia and tachycardia are common. At higher doses, delirium hallucination, psychosis and rhabdomyolysis (destruction of muscle tissue) have been observed. The overdose is difficult to achieve by conventional consumption of coffee or caffeinated drinks. However, there are food supplements that contain it in very concentrated amounts, up to 3 mg in some products sold in the United States for example. At this level of concentration, the lethal limit is not far and cases of lethal overdoses have already been identified. In 200, for example, a young American wrestler died in the middle of a fight. His autopsy will reveal the presence of 2014 micrograms of caffeine per liter of blood, more than 70 times the dose contained in soda or coffee. Energy drinks are responsible for the increase in the number of caffeine poisonings.
Energy drinks (Red Bull, Burn, Monster, etc.) are at the origin of the drastic increase in cases of caffeine poisoning since 2000. A cup of Robusta coffee contains around 115 mg of caffeine (between 1,5, 3 and 59%), it is twice as much as a cup of Arabica which has 120mg. There is approximately 2mg in an espresso and 80mg in a "decaf". Count 0,25 mg of caffeine in a 40 cl Red Bull and 33 mg in a 50 cl Coca Cola. Two teaspoons of tea contain between 150 and 100 mg of caffeine depending on the variety (white and green teas are very concentrated). Finally, 85g of 130% cocoa contains 15 mg of caffeine, while the same serving of milk chocolate contains “only” XNUMX mg.
To summarize :
- Caffeine, by its proximity to adenosine, crosses the blood-brain barrier that separates the blood circulation of the brain and that of the rest of the body.
- Caffeine inhibits adenosine, which is responsible for, among other things, the body's slow-wave sleep (physical repair), and increases the secretion of adrenaline and dopamine.
- Caffeine reduces the feeling of fatigue (and not the fatigue itself), acts as a psychostimulant and increases concentration while having a limited analgesic effect
- Caffeine, metabolized by the liver, also increases lipolysis (transformation of fat into glycogen and fatty acids), the amount of urine (diuretic effect) and acts, weakly, on the smooth muscles of the bronchi (treatment against asthma ).
Consumption and dependence
By crossing the blood-brain barrier, caffeine easily settles in the brain, which gets used to its presence and takes a taste. In regular coffee consumers, there is thus a multiplication of adenosine receptors, those which welcome caffeine. In fact, as with any addiction, for the same dose, the psychotropic effects become more and more reduced. Then, caffeine withdrawal, allowing the active return of adenosine, will multiply its physiological powers (fatigue, dilation of blood vessels leading to headaches, nausea, bradycardia, loss of concentration, etc.) and cause a sensation of lack, with all the withdrawal symptoms that come with it. We then notice the appearance of headaches, increased irritability, difficulty concentrating… These perverse effects generally disappear after five days, once the number of adenosine receptors has returned to their normal amount.
Many experts believe that the psychotropic effects of caffeine have long been overestimated because of these withdrawal symptoms: by comparing the states between a person on caffeine and a person who is deprived of it during their withdrawal period, the big difference is in glaring effect, but does not take into account the normal condition of the subject. Addiction occurs from 400 mg three times a day for seven days and dependence appears when consumption is continuous, as was the case with Balzac. The best way to wean yourself is to gradually reduce your intake and not stop suddenly. Be careful, “decaffeinated” coffees always contain significant amounts of caffeine.
To summarize :
- A dose of less than 500mg of caffeine / day (about 6 cups of coffee) is rarely dangerous
- Caffeine addiction, however, occurs quickly.
- Weaning is quick but can lead to painful ailments
- It is advisable to gradually reduce your dose of caffeine in order to wean without discomfort
- Decaffeinated coffees contain caffeine
Leads for Parkinson's disease
Like any psychotropic substance, caffeine therefore offers certain advantages and no less implacable drawbacks. Recent large-scale studies have shown that caffeine may reduce the risk of developing Parkinson's disease. The process is still poorly understood by researchers, but is believed to be linked to the balance of power between adenosine receptors (which multiply with prolonged or frequent use of caffeine) and dopamine receptors (which decrease when adenosine receptors are increase), involved in Parkinson's disease. Be careful though, the decrease in dopamine has many perverse effects, which can go as far as depression. Further proof of the ambiguity of caffeine, which always oscillates somewhere between poison and cure.
Leads for Parkinson's disease
« The first bans in sport logically focused on stimulants and it is even they who feed the longest list of prohibited substances. WADA specifies that "all stimulants are prohibited" and that all analogues, by chemical structure or biological effect, of a listed stimulant molecule are also prohibited. » explains Doctor Jacomet, member of the Monegasque Anti-Doping Committee. Caffeine definitely falls into that box. In fact, from 1999, when WADA was created, to 2004, caffeine was on the Prohibited List. Extensive consumption and the difficulty in achieving precise and fair controls forced WADA to remove caffeine from the List, much like the Sultan of Cairo in his day lifted the prohibition. "There is no other solution than to keep caffeine under surveillance since it can neither be authorized nor prohibited, as the World Sport Code would like," concludes Dr Jacomet. Caffeine is therefore returning to the monitoring program this year. the WADA List.
