Effect of caffeine on target detection and rifle marksmanship

Stress response to virtual reality based active shooter training: Impact of caffeine consumption

Participation in a virtual reality based active shooter training drill (VR-ASD) has been shown to increase biomarkers of stress; however, the impact of caffeine consumption on this response has not been studied. Caffeine ingestion has been shown to have favorable effects on physical and cognitive performance among athletic and tactical occupations alike. This study examined the impact of caffeine ingestion on subjective and physiological markers of stress in response to a mental stress task (MST) which involved participation in a VR-ASD and cognitive challenge consisting of mental arithmetic and a Stroop challenge. Fifty-three subjects were randomly assigned either caffeine (n = 26) or placebo (n = 27) prior to being exposed to the MST. Saliva samples, heart rate (HR), and state-anxiety inventory (SAI) scales, were collected before and after exposure to the MST. Saliva was analyzed for α-amylase (sAA), secretory IgA (SIgA), and cortisol (sCORT) concentrations. The MST resulted in significant increases in sAA, SIgA, HR, and SAI. Immediately post MST, sAA concentrations were significantly higher following the caffeine treatment compared to placebo. These data demonstrate that caffeine consumption results in significantly greater sAA concentrations post MST. This study was pre-registered as a clinical trial ("Impact of supplements on stress markers": NCT05592561).

Effects of caffeine, methylliberine, and theacrine on vigilance, marksmanship, and hemodynamic responses in tactical personnel: a double-blind, randomized, placebo-controlled trial

Background

Tactical athletes require fast reaction times (RT) along with high levels of vigilance and marksmanship performance. Caffeine has been shown to improve these measures but also results in increased blood pressure and jitteriness. Research on other purine alkaloids, such as methylliberine and theacrine, has suggested they do not increase blood pressure or jitteriness to the same extent, but their impact on tactical performance is unknown.

Methods

A between-subjects, randomized, placebo-controlled design was used to test the effects of placebo (PLA), 300 mg caffeine (CAF), and a combination of 150 mg caffeine, 100 mg methylliberine, and 50 mg theacrine (CMT) on RT and marksmanship along with hemodynamic and arousal measures following a sustained vigilance task in tactical personnel (n = 48). Following consumption of the supplement, participants underwent a 150-min protocol consisting of two rounds. Each round began with leisurely reading followed by a 30-min vigilance task before beginning two trials of movement and marksmanship tasks. Hemodynamics and felt arousal were assessed throughout the protocol. Composite Z-scores were calculated for overall performance measures at each timepoint, and mixed-effects models were used to assess differences in RT, accuracy, and composite Z-scores along with hemodynamics and felt arousal. An α-level of 0.05 was used to determine statistical significance, and Cohen’s d was used to quantify effect sizes.

Results

A Group-by-Time interaction for vigilance RT (P = 0.038) indicated improvements for both CAF and CMT from round 1 to round 2 (P < 0.01) while PLA did not change (P = 0.27). No Group main effects or Group-by-Time interactions were found for movement or marksmanship performance (P > 0.20). Group main effects for systolic (SBP; P = 0.001) and diastolic blood pressure (DBP; P = 0.028) indicated higher SBP in CAF (P = 0.003, d= 0.84) and CMT (P = 0.007, d= 0.79) compared to PLA but only higher DBP in CAF (P = 0.025, d= 0.74). No Group-by-Time interaction or Group main effect was found for felt arousal (P > 0.16).

Conclusions

These findings suggest similar benefits on RT during a vigilance task between CAF, containing 300 mg caffeine, and CMT above PLA, though CAF resulted in slightly less favorable hemodynamic changes. This study is the first to provide data showing similar efficacy of combined caffeine, methylliberine, and theacrine compared to double the caffeine dose consumed alone on vigilance RT but without a significant rise in DBP above PLA in tactical personnel.

Effect of caffeine ingestion on competitive rifle shooting performance

PURPOSE

The purpose of the present study was to test if caffeine ingestion affects rifle shooting accuracy in trained shooters.

METHODS

Twenty trained shooters performed 4 shooting tests in a randomized, double-blinded, placebo controlled crossover design; 2 identical tests after placebo ingestion and 2 after ingestion of 300 mg caffeine. The tests consisted of 30 shots in prone position and 30 in standing position on a 10 ring electronic target, on a distance of 50 metres, without any time limit, at rest.

RESULTS

Caffeine supplementation entailed a mean decrease in shooting performance by 11.8 points (95% CI: 6.7 to 17.0, effect size: 0.9). This was primarily a result of an 11.3 (95% CI: 7.2 to 15.4, effect size: 0.9) point decrease during shooting in standing position and not in prone position (0.6 point decrease, 95% CI: -2.1 to 3.2, effect size: 0.1).

CONCLUSIONS

We conclude that prior ingestion of 300 mg caffeine impairs rifle shooting accuracy in trained shooters when performed in standing but not in prone position.

The effects of caffeine on marksmanship accuracy and reaction time: a systematic review

Military and law enforcement personnel are required to maintain optimal marksman accuracy and reaction time during extended duty hours amidst environmental stressors. Although caffeine is commonly used to mitigate the consequences of fatigue, the effects of caffeine on marksmanship accuracy are inconclusive. The purpose of this review was to determine the effect of caffeine on marksman accuracy and reaction time. A literature search was conducted and 17 articles were selected for review based on relevance and methodological quality. Caffeine consistently improved marksman reaction time but did not improve marksmanship accuracy. However, there is some evidence that caffeine attenuates performance decrements in marksman accuracy caused by stress and fatigue if optimal dosing strategies are employed. Dosing strategies timed according to hours of wakefulness and time before testing could prevent performance deterioration. Doses of 100-200 mg every 2 hours may effectively improve accuracy during extended duty; however, further research is needed. Practitioner Summary: The purpose of this review was to determine the effect of caffeine on marksman accuracy and reaction time. A literature search was conducted and 17 articles were selected for review based on relevance and methodological quality. Caffeine consistently improved marksman reaction time but did not improve marksmanship accuracy.

Effects of Energy Beverage Consumption on Pistol Aiming Steadiness in Law Enforcement Officers

Monaghan, TP, Jacobson, BH, Sellers, JH, and Estrada, CA. Effects of energy beverage consumption on pistol aiming steadiness in law enforcement officers. J Strength Cond Res 31(9): 2557-2561, 2017-The popularity of energy drinks (EDs)/shots (ESs) has grown steadily over the years resulting in billions of dollars of sales annually. Energy drink marketing focuses on the improved performance and alertness and a reduction in fatigue. Although caffeine comprises one of the ingredients, it is not fully known how the combination of the many remaining active ingredients affects physical performance. The purpose of this study was to investigate the effect of a commercially available ES on pistol aiming steadiness. Subjects (N = 10) consisted of accredited police officers in the Midwest. A randomized, blinded, crossover design was used to evaluate the pistol aiming steadiness after the consumption of an ES or placebo. Pistol aiming steadiness was measured using a hole/stylus steadiness tester and laser attached to a training pistol before and 30 minutes after ES or placebo consumption. Analysis revealed that the ES significantly (p ≤ 0.05) impaired pistol steadiness, whereas the placebo yielded no significant difference in aiming steadiness. Based on these results, it was concluded that the consumption of an ES could compromise aiming accuracy and shot placement, thereby jeopardizing the health and welfare of law enforcement personnel.

Cognitive Performance during a 24-Hour Cold Exposure Survival Simulation

Survivor of a ship ground in polar regions may have to wait more than five days before being rescued. Therefore, the purpose of this study was to explore cognitive performance during prolonged cold exposure. Core temperature (T_c) and cognitive test battery (CTB) performance data were collected from eight participants during 24 hours of cold exposure (7.5°C ambient air temperature). Participants (recruited from those who have regular occupational exposure to cold) were instructed that they could freely engage in minimal exercise that was perceived to maintaining a tolerable level of thermal comfort. Despite the active engagement, test conditions were sufficient to significantly decrease T_c after exposure and to eliminate the typical 0.5–1.0°C circadian rise and drop in core temperature throughout a 24 h cycle. Results showed minimal changes in CTB performance regardless of exposure time. Based on the results, it is recommended that survivors who are waiting for rescue should be encouraged to engage in mild physical activity, which could have the benefit of maintaining metabolic heat production, improve motivation, and act as a distractor from cold discomfort. This recommendation should be taken into consideration during future research and when considering guidelines for mandatory survival equipment regarding cognitive performance.

Alcohol Use and Firearm Violence

Although the misuse of firearms is necessary to the occurrence of firearm violence, there are other contributing factors beyond simply firearms themselves that might also be modified to prevent firearm violence. Alcohol is one such key modifiable factor. To explore this, we undertook a 40-year (1975-2014) systematic literature review with meta-analysis. One large group of studies showed that over one third of firearm violence decedents had acutely consumed alcohol and over one fourth had heavily consumed alcohol prior to their deaths. Another large group of studies showed that alcohol was significantly associated with firearm use as a suicide means. Two controlled studies showed that gun injury after drinking, especially heavy drinking, was statistically significant among self-inflicted firearm injury victims. A small group of studies investigated the intersection of alcohol and firearms laws and alcohol outlets and firearm violence. One of these controlled studies found that off-premise outlets selling takeout alcohol were significantly associated with firearm assault. Additional controlled, population-level risk factor and intervention studies, including randomized trials of which only 1 was identified, are needed. Policies that rezone off-premise alcohol outlets, proscribe blood alcohol levels and enhance penalties for carrying or using firearms while intoxicated, and consider prior drunk driving convictions as a more precise criterion for disqualifying persons from the purchase or possession of firearms deserve further study.

Acute effects of caffeine supplementation on cortical arousal, anxiety, physiological response and marksmanship in close quarter combat

Previous studies have researched the ergogenic effect of caffeine in different shooting actions, but none of them in a stressful combat action. This study aimed to analyse the effect of a dose of 400 mg of caffeine monohydrate on the psycho-physiological response and marksmanship of soldiers in close quarter combat (CQC). We analysed the heart rate, blood lactate concentration, cortical arousal, state anxiety and marksmanship of 19 soldiers in the Spanish Army (38.9 ± 4.1 years; 177.4 ± 5.3 cm; 78.8 ± 7.6 kg) before and after a CQC simulation in a double-blind procedure. Caffeine intake did not improve shooting performance in CQC; however, it increased cognitive and somatic anxiety levels.

PRACTITIONER SUMMARY

According to the previous literature, the ingestion of caffeine could help soldiers in operations conducted in sleep deprivation conditions, but in stressful combat situations it does not improve the marksmanship of soldiers.