Stimulants cause increased physical and mental activity. They suppress the sensation of fatigue, increase performance and uplift the mood. The risk of dependence is high. The group of stimulants also includes illegal drugs such as cocaine and ecstasy. Stimulants are prohibited in competition.

The chemical structure of typical stimulants such as amphetamine or ephedrine is similar to that of adrenaline and noradrenaline, the body's own stress hormones produced in the adrenal medulla. As a result, their effect on the organism is also similar. By increasing, accelerating or improving nerve activity, they stimulate and imitate the sympathetic nervous system which controls blood vessels and glands.

This leads to an improvement in concentration and alertness, an increase in self-confidence and the suppression of fatigue. In addition, stimulants help the body achieve greater performance by widening the airways (improved oxygen uptake) and increasing cardiac output and heart rate (improved oxygen transport).

Administered stimulants act predominantly on the autonomic nervous system. They stimulate and imitate sympathetic activity, which increases alertness, boosts the body's energy turnover and delays fatigue. They raise body temperature, heart rate and blood pressure and uplift the mood (euphoria).

⬆ Sympathetic activity

⬆ Mood

Nervous system and brain

Stimulants act on the nervous system. The do not supply energy to the body but only activate the mobilisation of energy. Body temperature rises sharply and sensations of hunger and thirst are suppressed, leading to a major loss of fluid.

At high doses, the arousing effect of stimulants can quickly turn into restlessness, hyperexcitability and aggressiveness. Other possible consequences include persistent sleep disturbances as well as acute hallucinations, anxiety states, delusions and depression. The addiction potential is very high!

Because stimulants suppress the sensation of exhaustion, the body mobilises even the autonomously protected reserves, which can lead to total exhaustion and in extreme cases to death.

Cardiovascular and respiratory systems

Stimulants place strain especially on the cardiovascular system. Constriction of the blood vessels causes an increase in blood pressure and body temperature. This is life-threatening and can lead to a heart attack.

Heart rate irregularities, convulsive fits and circulatory failure can also be caused by the consumption of stimulants. Especially in conjunction with sporting activity, life-threatening respiratory paralysis can occur.

Stimulants are used particularly in competition because they improve concentration, suppress fatigue and make it possible to mobilise the autonomously protected energy reserves. These are the energy resources the body keeps specifically protected for emergency reactions, mainly to safeguard vital functions such as respiration, brain activity and blood circulation.

The most widespread abuse of stimulants occurs in endurance and power sports. But they are also frequently used in combat sports such as boxing.

Although stimulants are easily detectable, they continue to be abused for performance-enhancing purposes. In addition to anabolics, they are the second most frequent substance class detected by anti-doping laboratories worldwide.

Ephedrine and pseudoephedrine in over-the-counter cold remedies

Ephedrine, which is contained in many over-the-counter flu medicines, is a prohibited substance. It acts on the airways by relaxing the bronchi and decongesting the nasal mucosa. To avoid a positive test, athletes must stop taking such medicines at least 48 hours before competition.

Caffeine is not prohibited

From 1984 to 2004, caffeine was on the IOC/WADA Prohibited List. However, since tolerance and the breakdown of caffeine in the human body are subject to great individual variation and its stimulant effect is weak compared to other stimulants, caffeine was removed from the Prohibited List in 2004.

Cocaine

Positive doping tests for cocaine have emerged repeatedly in recent years. In 2012, cocaine was the second most frequent stimulant, following methylhexanamine, detected in doping controls. In sports such as football, ski jumping or tennis, well-known athletes have admitted to the consumption of cocaine. Examples include the former Austrian ski jumper Andreas Goldberger (one of the most successful ski jumpers of the 1990s) and the Romanian footballer Adrian Mutu, who had to pay Chelsea FC around 17 million euros in damages as a result of his cocaine abuse. Other athletes have tried, with greater or lesser success, to protest their innocence after positive tests for cocaine.