The effects of caffeine consumption onshooter performance, Positive or Negative?Introduction: Caffeine is odorlessand a bitter alkaloid which is found in tea, coffee, cola drinks,and chocolate (1, 2). See the Table 1 forcaffeine equivalents in common products (3). Table 1. Estimated caffeine content in commonproducts (3).
The amount of its metabolites level usually increases in theblood within 15–45 minutes after caffeine intake, and reaches to the peak levelafter an hour (1).Theabsorption of caffeine is slower when is consumed with a meal .But can beabsorbed faster by chewing caffeine-containing gum which allows for rapidabsorption through buccal tissue. Then, caffeine is distributed to all tissuesvery fast and passes easily through the blood-brain barrier for extending itseffects. The mean half-life of caffeine in the circulation is nearly 3–5 hour.It means that can be interacted with many tissues for a long time (3). InJanuary 2004, caffeine was one of several substances removed from theProhibited Substance List by the World Anti?DopingAgency, the supplement is still being closely monitored in doping tests.
This newstrategy permits caffeine consumption in sporting activities and competitionsfor the specific purposes of performance enhancement (1, 4).Low(40 mg or 0.5 mg /kg) to moderate (300 mg or 4 mg/ kg) doses of caffeineimprove alertness, attention and reaction time, but effects are less on memoryand higher-order executive function, such as judgment and decision making. Lowand moderate doses of caffeine don’t not alter significantly sensory functionsincluding vision or hearing.
Effects on physical performance includingtime-to-exhaustion, time-trial, muscle strength and endurance are observed bydose of more than 200 mg (3 mg/ kg) (3). See the Table 2 for caffeine dosesassociated with cognitive and physical effects. Table 2. Caffeine doses (mg/ kg body mass) associated with cognitive andphysical effects in both rested and sleep deprived individuals (3). Somestudies have demonstrated that caffeine supplementation improves power, speed,agility, attention, and reaction time in some sports. Now, caffeine is widelyused in various sports as an ergogenic aid. Unfortunately, there are limitedpublished studies on caffeine effects in precision sport activities such asshooting sport.Side-effectsof caffeine supplementations Theside-effects questionnaire of caffeine supplementation in shooters revealedthat commonly associated side-effects such as headache, anxiety, and tremor.
Caffeine administration can induce arm and hand tremor and interfere withshooting performance. Arm trembling was reported after a single cup of coffee including300–600 mg of caffeine. And also, 300 mg of caffeine caused a marked increasein body sway 40 min after caffeine ingestion compared with a placebo trial (5).
Figure 1: Physiological effects of caffeine (6). Whencaffeine ingested in excessive amounts for a long period, caffeine reaches totoxicity level (caffeinism), which including below symptoms:· Central nervoussystem symptoms: Headache, lightheadedness, anxiety, agitation, tremulousness,perioral and extremity tingling, confusion, psychosis, seizures. · Cardiovascular symptoms:Palpitations, chest pain.· Gastrointestinalsymptoms: Nausea and vomiting, abdominal pain, diarrhea, bowel incontinence,anorexia (2).Clinicianagree that there is no health risk with consumption of up to 400 mg (?5.5 mg/ kg for a 75 kg individual) of caffeine doses per day byhealthy adults (3). Whatquantity of intentional ingestion of caffeinated products is safe andappropriate for the shooting sport? The results of one study on professional shooters have showedthat taking 5 mg/kg of caffeine caused a significant increase in blood pressure,a significant increase in heart rate but a significant decrease in shooting performance.
Moreover, taking 3 mg/kg of caffeine caused a significant increase in blood pressure.But this amount of caffeine had no significant effect on the heart rate andshooting performance. Decreased of shooting performance maybe due to palpitation,agitation and tremors in body of shooter. The shooter loses his / herconcentration and steady in his / her shooting position. So, he/she likely firesa pendulum shot that increases the shooting error (1).In addition, caffeine caneffect on the nervous system and body temperature as effector factors .Studieson military soldiers have showed that caffeine can improve their shootingperformances’ under conditions of sleep deprivation. But during conventionalconditions, a low dose of caffeine had no effect onshooting performance and a medium dose of caffeine could worse shootingperformance (1, 7).
The findings of other studies have showed also thatcaffeine had no ergogenic benefit with respect to reaction time, targettracking times and, particularly, performance scores in the Olympic Double Trap ) The treatment groups ingested 2 mg caffeine / kg ofbody weight and 4 mg caffeine / kg of body weight((2). Consumption of 300 mg caffeine provided no performance benefit to shootingaccuracy and reaction time in traditional archery recurve bow discipline (8).Youcan see the results of one study on caffeine effects on shooters performances’in below.
Shooters ingested Nescafe classic coffee as caffeine and Nescafedecaffeinated coffee as placebo (9).Figure 2: Comparison Scores between Treatments (9). Figure 3: Comparison Scores between Rounds (1 round=10 shots) (9) Caffeinedidn’t show any effect on increasing mental concentration and reducingperception of tiredness in this study (9).
RecommendationsItis recommended that shooters look for other useful ways for improving theirperformances’ before considering the use of caffeine products as a supplementation.However, if shooters are interested in use of caffeine products during shootingtraining sessions, please request medical supervision to ensure the level ofconsumption is safe and appropriate. Some athletes experience a perceived orpsychological benefit from the ingestion of caffeine products. This means someindividuals are ‘caffeine responders’, while others are ‘no responders’ withcaffeine consumption. For both of them, we advise to follow a medical consultbefore consumption (4).