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

References

• Scofield DE, Kardouni JR. The tactical athlete. Strength Conditioning J. 2015;37(4):2–7.
   Web of Science ®Google Scholar
• Austin KG, Deuster P. Monitoring training for human performance optimization. J Spec Oper Med. 2015;15(2):102–108. .
   PubMedGoogle Scholar
• Guest NS, VanDusseldorp TA, Nelson MT, et al. International society of sports nutrition position stand: caffeine and exercise performance. J Int Soc Sport Nutr. 2021Jan; 18(1): 1
   PubMed Web of Science ®Google Scholar
• Faudone G, Arifi S, Merk D. The medicinal chemistry of caffeine. J Med Chem. 2021 Jun;64(11):7156–7178.
   PubMed Web of Science ®Google Scholar
• Horst K, Jenkins WL. The effect of caffeine, coffee and decaffeinated coffee upon blood pressure, pulse rate and simple reaction time of men of various ages. J Pharmacol Exp Ther. 1935 Apr;53(4):385–400.
   Google Scholar
• Thornton GR, Holck HGO, Smith EL. The effect of benzedrine and caffeine upon performance in certain psychomotor tasks. J Abnorm Soc Psych. 1939 34:96–113.
   Google Scholar
• Jacobson BH, Edgley BM. Effects of caffeine on simple reaction time and movement time. Aviat Space Environ Med. 1987 Dec;58(12):1153–1156.
   PubMed Web of Science ®Google Scholar
• Santos VG, Santos VR, Felippe LJ, et al. Caffeine reduces reaction time and improves performance in simulated-contest of taekwondo. Nutrients. 2014 Feb;6(2):637–649.
   PubMed Web of Science ®Google Scholar
• Souissi M, Abedelmalek S, Chtourou H, et al. Effects of morning caffeine’ ingestion on mood States, simple reaction time, and short-term maximal performance on elite judoists. Asian J Sports Med. 2012 Sep;3(3):161–168.
   PubMedGoogle Scholar
• Doyle TP, Lutz RS, Pellegrino JK, et al. The effects of caffeine on arousal, response time, accuracy, and performance in division I collegiate fencers. J Strength Cond Res. 2016 Nov;30(11):3228–3235.
   PubMed Web of Science ®Google Scholar
• Kamimori GH, Penetar DM, Headley DB, et al. Effect of three caffeine doses on plasma catecholamines and alertness during prolonged wakefulness. Eur J Clin Pharmacol. 2000 Nov;56(8):537–544.
   PubMed Web of Science ®Google Scholar
• McLellan TM, Kamimori GH, Voss DM, et al. Caffeine effects on physical and cognitive performance during sustained operations. Aviat Space Environ Med. 2007 Sep;78(9):871–877.
   PubMedGoogle Scholar
• Kamimori GH, McLellan TM, Tate CM, et al. Caffeine improves reaction time, vigilance and logical reasoning during extended periods with restricted opportunities for sleep. Psychopharmacology (Berl). 2015 Jun;232(12):2031–2042.
   PubMed Web of Science ®Google Scholar
• Johnson RF, Merullo DJ. Friend-Foe discrimination, caffeine, and sentry duty. Proc Hum Factors Ergon Soc Annu Meet. 1999;43(23):1348–1352.
   Google Scholar
• Tharion WJ, Shukitt-Hale B, Lieberman HR. Caffeine effects on marksmanship during high-stress military training with 72 hour sleep deprivation. Aviat Space Environ Med. 2003 Apr;74(4):309–314.
   PubMed Web of Science ®Google Scholar
• Gillingham R, Keefe AA, Keillor J, et al. Effect of caffeine on target detection and rifle marksmanship. Ergonomics. 2003 Dec;46(15):1513–1530.
   PubMed Web of Science ®Google Scholar
• Gillingham RL, Keefe AA, Tikuisis P. Acute caffeine intake before and after fatiguing exercise improves target shooting engagement time. Aviat Space Environ Med. 2004;75(10):865–871.
   PubMed Web of Science ®Google Scholar
• Shirlow MJ, Mathers CD. A study of caffeine consumption and symptoms; indigestion, palpitations, tremor, headache and insomnia. Int J Epidemiol. 1985 Jun;14(2):239–248.
   PubMed Web of Science ®Google Scholar
• Humayun MU, Rader RS, Pieramici DJ, et al. Quantitative measurement of the effects of caffeine and propranolol on surgeon hand tremor. Arch Ophthalmol. 1997 Mar;115(3):371–374.
   PubMedGoogle Scholar
• Jacobson BH, Thurman-Lacey SR. Effect of caffeine on motor performance by caffeine-naive and -familiar subjects. Percept Mot Skills. 1992 Feb;74(1):151–157.
   PubMed Web of Science ®Google Scholar
• Kaplan GB, Greenblatt DJ, Ehrenberg BL, et al. Dose-dependent pharmacokinetics and psychomotor effects of caffeine in humans. J Clin Pharmacol. 1997 Aug;37(8):693–703.
   PubMed Web of Science ®Google Scholar
• Mondal G, Wang YH, Butawan M, Bloomer, R J, Yates, C R, et al. Caffeine and Methylliberine: A Human Pharmacokinetic Interaction Study J Exerc Nutrition. 2021 5(3):14. doi:10.53520/jen2022.103124 .
   Google Scholar
• He H, Ma D, Crone LB, et al. Assessment of the drug-drug interaction potential between theacrine and caffeine in humans. J Caffeine Res. 2017 Sep;7(3):95–102.
   PubMedGoogle Scholar
• Wang YH, Mondal G, Butawan M, et al. Development of a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for characterizing caffeine, methylliberine, and theacrine pharmacokinetics in humans. J Chromatogr B Analyt Technol Biomed Life Sci. 2020 Oct;1155:122278.
   PubMed Web of Science ®Google Scholar
• VanDusseldorp TA, Stratton MT, Bailly AR, et al. Safety of short-term supplementation with methylliberine (Dynamine(R)) Alone and in Combination with TeaCrine(R) in young adults. Nutrients. 2020 Feb;12(3). doi:10.3390/nu12030654.
   Web of Science ®Google Scholar
• Bello ML, Walker AJ, McFadden BA, et al. The effects of TeaCrine(R) and caffeine on endurance and cognitive performance during a simulated match in high-level soccer players. J Int Soc Sport Nutr. 2019 Apr;16(1):20.
   PubMedGoogle Scholar
• Kuhman DJ, Joyner KJ, Bloomer RJ. Cognitive performance and mood following ingestion of a theacrine-containing dietary supplement, caffeine, or placebo by young men and women. Nutrients. 2015 Nov;7(11):9618–9632.
   PubMed Web of Science ®Google Scholar
• La Monica MB, Listman JB, Donovan I, Johnson, T E, Heeger, D J, Mackey, W E, et al. Effects of TeaCrine® (theacrine), DynamineTM (methylliberine), and caffeine on gamer psychomotor performance in a first-person shooter video game scenario. J Exerc Nutrition. 2021 4(2): 7 .
   Google Scholar
• Myers MG. Effects of Caffeine on Blood Pressure. Arch Intern Med. 1988;148(5):1189.
   PubMedGoogle Scholar
• Green PJ, Kirby R, Suls J. The effects of caffeine on blood pressure and heart rate: a review. Ann Behav Med. 1996 Sep;18(3):201–216.
   PubMed Web of Science ®Google Scholar
• Daniels JW, Mole PA, Shaffrath JD, et al. Effects of caffeine on blood pressure, heart rate, and forearm blood flow during dynamic leg exercise. J Appl Physiol. 1998 Jul;85(1):154–159.
   PubMed Web of Science ®Google Scholar
• Harber MP, McCurry A, Carlini N, et al. Caffeine ingestion alters central hemodynamics following aerobic exercise in middle-aged men. Eur J Appl Physiol. 2021 Feb;121(2):435–443.
   PubMed Web of Science ®Google Scholar
• Sung BH, Lovallo WR, Pincomb GA, et al. Effects of caffeine on blood pressure response during exercise in normotensive healthy young men. Am J Cardiol. 1990;65(13):909–913.
   PubMed Web of Science ®Google Scholar
• Taylor L, Mumford P, Roberts M, et al. Safety of TeaCrine(R), a non-habituating, naturally-occurring purine alkaloid over eight weeks of continuous use. J Int Soc Sport Nutr. 2016; 13: 2.
   PubMed Web of Science ®Google Scholar
• Bloomer RJ, Butawan M, Pence J. Acute impact of a single dose of Dynamine, TeaCrine, caffeine, and their combination on systemic hemodynamics and associated measures in men and women. Med Res Arch. 2020;8(4). 10.18103/mra.v8i4.2062
   Google Scholar
• Starosta AJ, Earleywine M. Assessing base rates of sexual behavior using the unmatched count technique. Health Psychol Behav Med. 2014 Jan;2(1):198–210.
   PubMedGoogle Scholar
• Barry RJ, Clarke AR, Johnstone SJ. Caffeine and opening the eyes have additive effects on resting arousal measures. Clin Neurophysiol. 2011 Oct;122(10):2010–2015.
   PubMed Web of Science ®Google Scholar
• Barry RJ, Clarke AR, Johnstone SJ, et al. Timing of caffeine’s impact on autonomic and central nervous system measures: clarification of arousal effects. Biol Psychol. 2008 Mar;77(3):304–316.
   PubMed Web of Science ®Google Scholar
• Barry RJ, Rushby JA, Wallace MJ, et al. Caffeine effects on resting-state arousal. Clin Neurophysiol. 2005 Nov;116(11):2693–2700.
   PubMed Web of Science ®Google Scholar
• Astorino TA, Cottrell T, Talhami Lozano A, et al. Effect of caffeine on RPE and perceptions of pain, arousal, and pleasure/displeasure during a cycling time trial in endurance trained and active men. Physiol Behav. 2012 May;106(2):211–217.
   PubMed Web of Science ®Google Scholar
• Richardson DL, Clarke ND. Effect of coffee and caffeine ingestion on resistance exercise performance. J Strength Cond Res. 2016 Oct;30(10):2892–2900.
   PubMed Web of Science ®Google Scholar
• Clarke ND, Kornilios E, Richardson DL. Carbohydrate and caffeine mouth rinses do not affect maximum strength and muscular endurance performance. J Strength Cond Res. 2015 Oct;29(10):2926–2931.
   PubMed Web of Science ®Google Scholar
• Backhouse SH, Bishop NC, Biddle SJ, et al. Effect of carbohydrate and prolonged exercise on affect and perceived exertion. Med Sci Sports Exerc. 2005 Oct;37(10):1768–1773.
   PubMed Web of Science ®Google Scholar
• Dempster P, Aitkens S. A new air displacement method for the determination of human body composition. Med Sci Sports Exerc. 1995 Dec;27(12):1692–1697.
   PubMed Web of Science ®Google Scholar
• McCrory MA, Gomez TD, Bernauer EM, et al. Evaluation of a new air displacement plethysmograph for measuring human body composition. Med Sci Sports Exerc. 1995;27(12):1686–1691.
   PubMed Web of Science ®Google Scholar
• McCrory MA, Mole PA, Gomez TD, et al. Body composition by air-displacement plethysmography by using predicted and measured thoracic gas volumes. J Appl Physiol. 1998 Apr;84(4):1475–1479.
   PubMed Web of Science ®Google Scholar
• Brozek J. Body composition: models and estimation equations. Am J Phys Anthropol. 1966 Mar;24(2):239–246.
   PubMed Web of Science ®Google Scholar
• Wells AJ, Hoffman JR, Beyer KS, et al. Reliability of the dynavision d2 for assessing reaction time performance. J Sports Sci Med. 2014 Jan;13(1):145–150.
   PubMed Web of Science ®Google Scholar
• Hogg JA, Carlson LM, Rogers A, et al. Reliability and concurrent validity of TRAZER compared to 3-dimensional motion capture. J Clin Trans Res. 2021;7(1):100–107.
   Google Scholar
• Buckley S, Chaput M, Simon JE, et al. Cognitive Load Impairs Time to Initiate and Complete Shooting Tasks in ROTC Members. Mil Med. 2022 Jul 187(7–8): e898–e905.
   PubMed Web of Science ®Google Scholar
• Ostchega Y, Nwankwo T, Sorlie PD, et al. Assessing the validity of the Omron HEM-907XL oscillometric blood pressure measurement device in a national survey environment. J Clin Hypertens (Greenwich). 2010 Jan;12(1):22–28.
   PubMed Web of Science ®Google Scholar
• Pasadyn SR, Soudan M, Gillinov M, et al. Accuracy of commercially available heart rate monitors in athletes: a prospective study. Cardiovasc Diagn Ther. 2019 Aug;9(4):379–385.
   PubMed Web of Science ®Google Scholar
• Svebak S, Murgatroyd S. Metamotivational dominance: a multimethod validation of reversal theory constructs. J Pers Soc Psychol. 1985;48(1):107–116.
   Web of Science ®Google Scholar
• Team RC. R: a Language and Environment for Statistical Computing. Vienna Austria: R Foundation for Statistical Computing; 2021.
   Google Scholar
• Bates D, Mächler M, Bolker BM, et al. Fitting linear mixed-effects models usinglme4. J Stat Softw. 2015;67(1). 10.18637/jss.v067.i01.
   Web of Science ®Google Scholar
• Lenth R. emmeans: estimated marginal means, aka least-squares means. R package version 1.4.7. 2021.
   Google Scholar
• Ben-Shachar M, Lüdecke D, Makowski D. effect size: estimation of effect size indices and standardized parameters. J Open Source Softw. 2020;5(56):2815.
   Google Scholar
• Wickham H. ggplot2: elegant graphics for data analysis. New York: Springer-Verlag; 2016.
   Google Scholar
• Kjeldsen SE, Mundal R, Sandvik L, et al. Exercise blood pressure predicts cardiovascular death and myocardial infarction. Blood Press Monit. 1997 Jun;2(3):147–153.
   PubMedGoogle Scholar
• Mundal R, Kjeldsen SE, Sandvik L, et al. Exercise blood pressure predicts mortality from myocardial infarction. Hypertension. 1996 Mar;27(3):324–329.
   PubMed Web of Science ®Google Scholar
• Kamimori GH, Johnson D, Thorne D, et al. Multiple caffeine doses maintain vigilance during early morning operations. Aviat Space Environ Med. 2005 Nov;76(11):1046–1050.
   PubMedGoogle Scholar
• Torres C, Kim Y. The effects of caffeine on marksmanship accuracy and reaction time: a systematic review. Ergonomics. 2019 Aug;62(8):1023–1032.
   PubMed Web of Science ®Google Scholar
• Knapik JJ, Steelman RA, Trone DW, et al. Prevalence of caffeine consumers, daily caffeine consumption, and factors associated with caffeine use among active duty United States military personnel. Nutr J. 2022 Apr 14 21(1):22.
   PubMed Web of Science ®Google Scholar
• Greaves MM. Caffeine intake among law enforcement officers participating in shift work. Greenville NC: East Carolina University; 2013.
   Google Scholar
• Silverman IW. Sex differences in simple visual reaction time: a historical meta-analysis. Sex Roles. 2006;54(1–2):57–68.
   Web of Science ®Google Scholar