The hidden dangers of stimulants on the sports field

Stimulants are popular among athletes and exercise fanatics, although mostly prohibited. Those taking the risk may be unaware that they contain substances with dangerous side effects that can cause injury or death.

Sporting ideals are generally centred on health, comradeship and playing the game. But gradually sport has become more about winning and less about playing. The motivation to win is largely based on money and fame and people will take risks or cheat for either. And it’s not just the competition itself, athletes use supplements and stimulants for training too. 

Leaving aside the fact that doping is banned in most countries and prohibited by most sporting bodies, there are other negative consequences of the use of all drug stimulants and supplements. The use of anabolic steroids has been illegal for years but is rumoured still to happen as scientists find new ways to hide the tell-tale signs of drug use. 

Clinicians are becoming increasingly alarmed that some products contain dangerous chemicals that are unrecognised and untested or both. In 2021, Dr Pieter Cohen, Associate Professor of Medicine at Harvard Medical School, said: “We’re urging clinicians to remain alert to the possibility that patients may be inadvertently exposed to experimental stimulants when consuming weight loss and sports supplements.” Steroids are primarily used to build muscle strength and their dangerous side effects such as infertility, heart problems and psychiatric disorders, are well known. However, there are grave risks in using other types of drugs, especially stimulants that are less well recognised.

Although stimulants can boost physical performance and promote aggressiveness on the sports field, they have side effects that can impair athletic performance, including:

  • Nervousness and irritability
  • Heart and circulatory problems
  • Insomnia
  • Poor concentration
  • Dehydration

Central nervous system (CNS) stimulants come in various forms and are often used to reduce tiredness and increase alertness and competitiveness. The most commonly used stimulants such as caffeine, amphetamine and cocaine can all be used deliberately to enhance sporting performance, but sportsmen and women may sometimes get themselves into trouble inadvertently, unaware that their recreational use of drugs has not worn off before they do sports. 

Here are the most common stimulants and the main dangers associated with them:


Caffeine is not currently a banned substance in sport, but its use is being monitored by the World Anti-Doping Agency (WADA). Caffeine is found in many energy drinks as well as tea and coffee. Some energy drinks contain huge amounts of caffeine which can lead to high blood pressure, insomnia, extreme restlessness and dehydration. Although caffeine is perhaps the least harmful stimulant taken by sportspeople, energy drinks, which typically contain large amounts of sugar as well, can negatively impact a person’s health if taken excessively.


These CNS drugs increase alertness and concentration leading to feelings of increased vigour and decreased appetite. They are therefore commonly used for weight loss as well as performance enhancement. They have been banned by WADA but are thought to still be in use by some athletes in forms modified to escape detection. Despite the associated risks, some sportspeople are tempted to use them because small doses may improve awareness, energy and reactions, resulting in slightly better performances.

Amphetamines may not directly damage the body tissues as much as say, steroids but the danger lies in the psychological effects of high doses which manifest as euphoria, inattention and a distorted sense of fatigue and pain. These can lead sportspeople to over-exercise or continue playing after injury with sometimes disastrous long-term consequences. 

Other side effects such as poor balance, increased reaction times, poor coordination and decreased ability to follow directions can also have serious consequences to the user and to others on the sports field with whom they might come into contact.

Sustained misuse of amphetamines at high doses can result in heart and circulatory problems and severe psychosis.


Ephedrine stimulates the heart rate and raises blood pressure. The side effects are similar to those of amphetamines. Athletes have seen ephedrine as a way to unfairly enhance their power, endurance, strength and speed. However, WADA tolerates the medical use of ephedrine within certain limits. This may seem surprising considering a number of well-publicised sporting tragedies where ephedrine has been present. Higher levels (above 10mg/ml) are prohibited.

Ephedrine is present in many nutritional supplements and pharmaceuticals such as decongestants and treatments for coughs, colds and some allergies. These can often be bought without a prescription which may explain the limit allowed by WADA. There is also a danger, however, that sportspeople who self-medicate for common complaints may unknowingly participate in sports while retaining ephedrine levels that pose a danger to themselves and others.


As the most potent natural stimulant, cocaine is a highly popular recreational drug. It is also significantly addictive leading the user to desire larger and more frequent amounts. Contrary to general belief, cocaine does not significantly enhance performance and indeed long-term use can lead to loss of concentration and energy, anxiety and paranoia. Although it may have some legitimate medical uses, it has long been banned by WADA and the IOC.

Nevertheless, cocaine continues to be misused in sports, particularly by those requiring a short burst of intense energy such as sprinting, where the perception is that relatively low doses can improve alertness and general arousal, thus enhancing performance.

Cocaine directly affects the body, causing changes to blood components which lead to a serious risk of heart and respiratory failure. Strokes and heart attacks are not uncommon. The use of cocaine and alcohol together is particularly cardiotoxic.

The addictive nature of cocaine often leads to chronic use and dependence. This in turn leads users to other drugs to help with the low feelings and depression that commonly follow a cocaine binge.

Dealing with stimulant abuse in sports

Few people would disagree that any stimulant or supplement has no place in the sport of any kind. Not only does such use contradict the lofty ideals of sportsmanship and honesty but it also has the potential for dire consequences such as injury, psychosis or death. World governing bodies such as WADA and the IOC address this and their testing programme for banned substances has considerable success. More education of the general public on the dire consequences of drug use in sports would be welcome. 

Away from the big events, it is much more difficult to deal with the problem at lower levels. Sportsmen and women at the grassroots are seldom tested. Such people are able to obtain many ‘performance enhancing’ drugs quite easily and may be unaware of the dangers they pose to themselves or others.

Again, at lower levels of the sports world, players may be participating while completely unaware of the residue of drugs still in their bodies from recent recreational use and the negative consequences that can result.

At Castle Craig, we regularly see the damage that supplements and stimulants can do to sportspeople at all levels. We also see how frequent use of one drug leads to another and how easily sportspeople can become addicted not just to substances but to gambling and other behaviours. Our clinic has successfully treated many sportspeople suffering with drug addiction and alcoholism. Patients work through our treatment programme under the guidance of a personal therapist while also addressing any co-occurring issues.