Caffeine Use & Water Polo: Exploring the Use of Caffeine on Athlete Performance

Abstract

Caffeine is widely used by athletes to enhance performance by combining its stimulant effects with nutrition, training, recovery and mental focus.  This research paper explores the impact of caffeine on enhancing athletic performance, particularly those that require endurance, explosive strength, or a mix of both.  The paper reviews existing research of the full spectrum of caffeine’s physiological effects on athletes themselves, detailing both its positive contributions to near-immediate athletic performance—such as improved muscular strength, endurance, and reduced perceived exertion—and its potential negative consequences post competition, including anxiety, insomnia, and impaired sleep quality.   The paper calls into question the presence of any benefit to performance that could come from caffeine use for athletes in skill-based sports.  Despite the absence of studies specific to the use of caffeine to meet the unique demands of water polo, which require both endurance and explosive strength, the paper predicts the likely consequences by analogy to other sports studies that do exist.  With the available data heavily focused on the short-term benefits and side effects, little is known about the longer-term effects of continuous caffeine use on either an athlete’s performance in their sport of choice or their personal health.  Given both the prevalence and acceptance of caffeine use as part of an athlete’s winning formula, an athlete deserves more information in order to make the right and informed decision for themselves.  It is uncertain what an athlete should do in the meantime, and at what cost to their athletic pursuits and health and wellness.

Introduction

For most athletes, their performance in their sport is many times what’s most important to them in terms of how they see themselves and measure their successes. When competing in any sport, athletes strive to be the best they can be – they seek to maximize their athletic performance. Athletes come to understand over time that maximizing their athletic performance comes from a critical combination of nutrition, hydration, recovery, performance weakness identification and correction, regimented training, and a positive mental perspective.

Many sports require a sudden burst of energy – think power lifting, 100-meter dash, 50- meter swimming events – while other sports require endurance or sustaining athletic performance over an extended period of time – think long-distance running, swimming or cycling. Some sports require a combination of the two – think water polo. While an athlete’s performance on any given day is based largely on discipline with those factors above over a period of time leading up to the competition, achieving an athlete’s peak performance on competition day can also be influenced by last-minute preparations which may be just an hour or less prior to competing. For example, an athlete might consume an energy bar or hydration drink. It’s also well known that athletes may turn to ingesting food or drink just prior to competition that includes naturally occurring stimulants – such as caffeine – to get that burst of energy or to carry them through a long event. But does it truly work? Can caffeine maximize athletic performance potential on a given day? If it can, there must be a host of other considerations that athletes should consider in making decisions related to the use of caffeine.

Literature Review

Caffeine is a stimulant drug. A stimulant, also known as psychostimulant or central nervous system (CNS) stimulant, increases energy, awareness, and activity of the CNS (Evans, et al., 2024). According to Evans et al. (2024), some of the most common, naturally-occurring sources of caffeine are cacao beans and tea leaves. Caffeine can be added to sodas and energy drinks. Energy drinks are one of the most common consumables that athletes get their source of caffeine (Graham, 2001).

As a stimulant, caffeine increases the activity in the brain and throughout the nervous system. This happens by caffeine acting as an adenosine receptor antagonist. That means caffeine blocks adenosine which are neurotransmitters that make a person relaxed and sleepy (Ganio, et al., 2008). Caffeine is absorbed in the gastrointestinal tract and then metabolized by the liver. After ingestion, caffeine starts to circulate into the blood stream within 15–45 minutes (Penney, 2013). It can cross the membranes of nerve and muscle cells, including the blood-brain barrier.

Dosage awareness is an important factor when responsibly consuming caffeine. Unfortunately, many people consume caffeine without knowing the amount that may be present in their food and drink. For example, one can of cola (12 oz.) is around 30-47 mg of caffeine (Penney 2013). The optimal dosage of caffeine a person should take in a day is ~200 mg (Guest, et al., 2022). For athletes, taking even low doses of caffeine has shown to enhance an overall performance by optimizing their energy. Low doses of caffeine improve cognitive performance, vigilance, alertness, and mood during and after exercise. Athletes are sensitive to low doses late in prolonged exercise without ingesting any caffeine before the workout (Spriet 2014).

Researchers have found that taking caffeine 60 minutes before actively is most effective (Guest, et al., 2022). The consumption of caffeine causes maximum plasma peaks of the substance 30 and 90 minutes after consumption (Martins, et al., 2020). On the other hand, taking higher doses than recommended does not necessarily improve an athlete’s physical performance. This is due to the athlete feeling more fatigue and anxiety when ingesting a higher dosage. Higher doses of caffeine can lead to urine caffeine concentrations higher than 15 ug/ml, which is illegal in the National Collegiate Athletic Association (NCAA) (Guest, et al., 2022).

Ignoring the use of caffeine in connection with a sporting event, the use of caffeine is recommended to be in the morning or early afternoon. The later in the day that caffeine is ingested, the more likely it can cause insomnia.

Caffeine Effects on Athletes

Caffeine had been included on the World Anti-Doping Agency’s (WADA) list of banned substances, as it was considered to be an ergogenic aid. Ergogenic aids are substances that athletes use to gain a boost in their athletic performance and increase their time to exhaustion. There are 5 types of ergogenic aids: mechanical, psychological, physiological, pharmacological, and nutritional (Ivy, 2025). Mechanical aids are devices or equipment that are used to improve an athletes performance, such as specialized footwear. The second ergogenic aid is psychological which is influencing the mental processes that improve focus, motivation, and mental resilience, such as making smaller goals to reach a bigger goal.

Next, physiological aids are techniques or methods such as recovery that affect the body’s natural functions to improve performance. Pharmacological aids such as steroids are medical or pharmaceutical mechanisms to enhance an athlete’s performance. Finally, nutritional aids affect one’s metabolism or an effect on the central nervous system by increasing lean body mass or muscle mass (Maughan, 1999).

Caffeine was banned as being an ergogenic aid. In the years that followed its ban, the athletic world began to embrace its use under the belief and experience that it will help an athletes achieve peak performance on a competition day. Due to that increased in popularity of the drug, it was removed from the list of banned substances for sports in 2004 (Jordan, et al., 2022). However, achieving peak performance from the use of caffeine may come at the cost of an athlete’s health and possibly future athletic performance. We first explore the positive effects before pivoting to the negative consequence of the use of caffeine in sports.

Positive Effects of Caffeine Use on Athletic Performance

Caffeine has many benefits to an athlete’s performance in their sport. Researchers have found that caffeine advances muscular strength and power, endurance performance, sport-specific skills, anaerobic power, and cognitive functions (Grgic, et al., 2018). Athletes use caffeine to boost their energy, resulting in increased competition. It is possible that caffeine uses can improve athletic performance by 10% (Penney, 2013).

Caffeine has a strong, positive effect on sports that focus on endurance and strength, such as swimming, weightlifting, and running (Grgic, et al., 2018). Since caffeine enhances strength, athletes use caffeine as an advantage in these kinds of sports, such as reducing RPE (Rate of Perceived Exertion; Doherty, et al., 2005). Athletes that participate in sports that focus on strength and endurance use the nerves and other side effects of caffeine to enhance their performance.

Athletes commonly ingest caffeine because it has been said to give athletes more energy. Caffeine has been reported to improve physical performance by increasing mobilization of intracellular calcium, increasing free fatty acid oxidation, and serving as an adenosine receptor antagonist in the CNS (Ganio, et al., 2008). The use of caffeine for athletes has been reported to improve endurance time to exhaustion (Penney, 2013). Due to the increase in endurance, athletes tend to keep ingesting more caffeine to increase this time range to exhaustion. Researchers have found that caffeine should be taken both before and after exercise to enhance an athlete’s performance (Tallis, et al., 2022).When increasing endurance time to exhaustion it can decrease pain and levels of fatigue allowing an athlete to keep pushing past the limit they usually peak at (Featherstone Nutrition 2022). Finally, caffeine can significantly decrease DOMS (DelayedOn Set Muscle Soreness) after working out.

Negative Effects of Caffeine Use by Athletes

While research has demonstrated several positive performance outcomes from caffeine use, there are frequent negative side effects that athletes experience when using caffeine. Caffeine is known for causing headaches, anxiety, and insomnia (Berg, 2025). When taking caffeine, athletes need to be very careful when they decide to ingest caffeine because different times of the day can diminish sleep quality. When caffeine is ingested in the late afternoon it can affect a person’s ability to fall asleep and stay asleep. Caffeine can negatively affect sleep latency, sleep quality, and post-sleep perception of wakefulness (Tallis et al., 2022). 

The lack of sleep negatively affects a person’s mood, reducing aspects of cognitive and physical activity functions. The less sleep an athlete gets the more their athletic performance is negatively impacted. Sleep disruption happens most commonly when ingesting within three hours before someone sleeps (Gardiner, et al., 2024). When a person consumes caffeine, it can disrupt the timing of your body clock. Caffeine does not only affect your total time of rest but it affects the amount of sleep a person actually enjoys. Another study found that caffeine can also cause depression, irritability, nausea, and stiffness (Martins, et al., 2020). People who experience anxiety, high blood pressure, heart issues, poor sleep quality, and stomach concerns are strongly recommended to stay away from caffeine due to caffeine possibly worsening those problems.

Finally, sports that are more skill based (as opposed to strength of endurance based) are more likely to have a negative effect from caffeine – think marksmanship sports. Skill based sports use fine motor skills and precision. Athletes that are in skill based sports may experience reduced performance as a result of the effects of “jitters”, shakiness, and nervousness that caffeine can cause. The side effects of caffeine withdrawal usually occur more towards 12-48 hours after ingestion (Martins, et al., 2020). Caffeine has even more side effects such as increase in urination, tachycardia (rapid heart rate), nervousness, fatigue, and GI issues (Tallis, et al., 2022).

Caffeine Use and Water Polo Performance

One sport that has not been extensively studied specifically is the intersection of athlete caffeine use within the sport of water polo. Water polo is the perfect example of a sport where it demands both long endurance and sudden bursts of force and strength. The endurance demands come from the requirement to sustain yourself in the pool by swimming or treading water for the duration of the match, combined with the constant turn-over of play from offense to defense at a high rate of frequency requiring constant swimming of the length of the pool. The sudden bursts come from (i) break-aways which require players to swim at their top possible speed, (ii) the constant pushing and pulling high-contact interplay between players regardless of whether they possess the ball, and (iii) when a player has the opportunity to take a shot on goal (which also triggers a commensurate burst of energy from the goal tender attempting to block the attempt). To fully appreciate the demands of the sport of water polo, let’s summarize how the sport is played.

Water Polo: Rules & Gameplay

Water polo is played by two opposing teams, each made up of six players in the water, a goalie, and additional players who are on the bench. The goal of the sport is to make offensive advantages to score the most goals against the other team. Athletes must travel up and down the pool playing offense and defense while also following several key rules. For example, two key rules of the game is that a player can only touch the ball with one hand and players can not touch the bottom of the pool. There are many other rules governing fouls, player position restrictions,, player ejections, and many more. If a player is being too aggressive or is preventing another player from making forward progress, that player will be ejected for 20 seconds. This team who is on offense gains an extra player advantage, which significantly increases the chance that the team will score a goal in that 20 seconds. If or when that player gets a total of three ejections they will be removed from play for the remainder of the game.

A game lasts for four periods that range from 6-8 minutes depending on the tournament and state rules. Water polo players often train both in and outside of the pool. Players often lap swim and lift weights to keep up their endurance. Most water polo players in their off season join a swim team or just swim laps to stay in shape.

Caffeine Use in Water Polo

Due to water polo being a both strength and endurance heavy sport, caffeine was shown to improve a water polo athlete’s performance in terms of swimming (one of many skills required of the sport, in the absence of any water polo specific studies). In a study performed by Cambridge found that when a competitive swimmer ingested caffeine it took less time to complete a 50-meter swimming competition (Lara, et al., 2015). At the time of ingestion, the athlete had not yet felt the negative side effects.

When taking caffeine, it takes time for side effects such as jitters and anxiety to appear. Water polo relies on a lot of swimming to get a player across the pool up to approximately 100 times per game. When ingesting caffeine, a player’s time to get across the pool will be reduced. A water polo player’s sleep would also be expected to be negatively affected when ingesting caffeine, consistent with overall studies that had those results. Caffeine most negatively affects an athlete’s sleep when they have a late-night competition and take caffeine well into the evening. Similarly, a water polo player can still feel moody or feel fatigue the day after consuming caffeine. Most athletes believe they need to rely on energy drinks or coffee to get them through their game and don’t contemplate how it could negatively affect them following play.

Caffeine improves an athlete’s muscles by the activation of the CNS. It can even improve a player’s ability to burn fat through lipolysis (Warwick, 2021). Most water polo athletes decide to do weight training when they are out of the water to build muscle to better their ability in the water. When it comes to weight training, caffeine increases the strength output and perceived effort of exercise. When caffeine is ingested during weight training it increases the calcium that is released in muscle cells. When there is an increase of calcium in muscle cells boosts an athlete’s strength. In addition to boosting strength, caffeine helps the body use fat for energy with lower the chances of fatigue. So, while the effects on a water polo player from the consumption of caffeine can be predicted based on the general studies, the unique impacts to water polo players remain unknown and unresearched.

Conclusion

The full effect of caffeine on an athlete’s performance is likely not fully known. Much of the available research appears to be based on the near-term measurable and quantitative effects, both positive and negative, on athletes’ performance as well as other matters such as the impact on sleep patterns.

In order to make informed decisions to use or not use caffeine, athletes should have access to deeper information regarding the long-term effects of using caffeine for sports performance which doesn’t exist today. Further, just as all sports are different in their demands, the effects of caffeine on athletes in different sports most certainly varies but little comparative information by sports category exists. Finally, the measurable, scientific evidence should be supplemented with evidence that can only be gathered by thoughtful and probing interviews of the athletes themselves. How they feel from the use of caffeine and the perspectives and advice that they could share is an important element of the complete set of data that is largely missing.

Until further studies can be completed to round out the full picture, the age-old advice of “use in moderation” that is attached to so many things we consume in life must certainly applies here.

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