Caffeine

This study will examine whether caffeine improves cognitive and competitive performance in professional chess players during tournament-style games. In a randomized double-blind crossover design, participants will complete two experimental sessions in which they consume either caffeinated coffee or decaffeinated coffee before playing a standardized chess match. Cognitive performance will be assessed using attention and reaction-time tests, including the Stroop Test, Trail Making Test, and Puzzle Rush task. Chess performance outcomes such as move accuracy, time management, and error rates will also be evaluated. The study aims to determine whether moderate caffeine intake enhances focus, alertness, and decision-making during prolonged competitive chess play.

The goal of this study is to understand how caffeine and alcohol affect the ocular and physiological systems, especially how the pupil (the aperture in the colored part of the eye) responds to light. It will also test whether these changes can be used to detect recent caffeine or alcohol intake using a portable eye device. The main questions it aims to answer are: 1. How does caffeine change pupil responses, eye movements, and other ocular and physiological measurements? 2. How does alcohol change these same ocular and physiological responses? 3. Are the effects of caffeine and alcohol different from each other? 4. Can these changes be used to accurately identify whether someone has consumed caffeine or alcohol? Researchers will compare caffeine, alcohol, and a placebo (a look-alike drink with no active substance) to see how each affects the ocular and physiological outcomes. Participants will: 1. Attend three separate sessions where they will consume caffeine, alcohol, or a placebo (in random order) 2. Undergo pupillary response evaluation using a handheld device that measures responses to different colored light stimuli 3. Have their eye movements analyzed 4. Have retinal and choroidal thickness, blood perfusion, and ocular oxygen levels measured 5. Have basic body measurements recorded (such as pulse rate and blood pressure) 6. Complete tests at multiple time points over 2 hours after consumption The results of this study may help develop a quick and non-invasive way to detect recent caffeine or alcohol use for clinical and safety purposes.

This study aims to evaluate the efficacy of sublingual caffeine in reducing recovery time and incidence of postoperative agitation in elderly patients undergoing general anesthesia.

The goal of this pilot clinical trial is to test if it is possible to conduct a larger study on the use of caffeine in preterm infants who need help with their breathing. It will also look at whether caffeine helps these infants get healthy enough to leave the hospital sooner. The main questions the researchers aim to answer are: Can the investigators successfully recruit and keep enough participants in the study? Do the medical teams follow the study drug instructions correctly? Does caffeine reduce the total time infants spend in the Neonatal Intensive Care Unit (NICU)? Researchers will compare caffeine to a placebo (a look-alike substance with no active medicine) to see if caffeine is a helpful treatment for babies born between 28 and 34 weeks of gestation who are using a breathing machine or oxygen. Participants will: Be randomly assigned to receive either caffeine or a placebo through an IV or a feeding tube. Receive the study treatment once a day as long as they require respiratory support (and for 24 hours after they stop). Be monitored by the research team for clinical outcomes like feeding progress, breathing stability, and growth until they are discharged from the hospital.

This study will evaluate post-beverage subjective caffeine responses and physiological responses to caffeinated beverage variations in generally healthy adults.

This study will evaluate post-beverage subjective caffeine responses and physiological responses to caffeinated beverages in generally healthy adults.

This clinical trial will be a comparison between personalized recommended caffeine dosing regimen versus the standard recommended caffeine dosing regimen for sustaining performance during sleep deprivation and minimizing side effects and subsequent sleep disruption. The questions this study aims to answer are: Whether the personalized caffeine recommendations improve vigilance, sleepiness, and cognition after total sleep deprivation, compared to standard recommendations; Whether the personalized caffeine recommendation better addresses the physical and emotional side effects of total sleep deprivation, compared to standard recommendations; And whether personalized caffeine recommendations aids in better recovery sleep after total sleep deprivation, compared to standard recommendations. Participants will be asked to: 1. Complete a 13-day at-home portion, wearing an actigraph watch to measure activity and sleep, and complete motor vigilance tests up to six times a day. 2. Complete a 4-day in-lab portion, where participants will have to complete one night of baseline sleep, undergo 62-hours of total sleep deprivation, and then complete one night of recovery sleep. 3. During the in-lab portion of the study, participants will be asked to complete more motor vigilance tests. Researchers will be comparing the personalized caffeine recommendation group against the standard caffeine recommendation to see if it is better at addressing each of the main questions.

Maintaining a stable core temperature is vital for physiological function; yet, exercise in heat can be problematic, and there is risk of exertional heat-related illness (Flouris \& Schlader, 2015; Leyk et al., 2019; Périard et al., 2021; Tyler et al., 2016; Veltmeijer et al., 2015). While aerobic fitness improves heat tolerance (Alhadad et al., 2019), strategies like acclimation and pre-cooling also mitigate heat stress (Casadio et al., 2016; Lorenzo et al., 2010; Ross et al., 2013; Siegel et al., 2010). Caffeine, an ergogenic aid (Del Corso et al., 2011; John et al., 2024), is known to enhance performance via adenosine antagonism and increased catecholamines in normothermic environments (Fredholm et al., 1999; Graham \& Spriet, 1991). However, effects in heat are inconsistent (Ganio et al., 2009; Zhang et al., 2014), possibly due to caffeine reducing the ability to thermoregulate effectively. Therefore, the aim of this study is to investigate the effects of a moderate dose of caffeine (5 mg/kg) on thermoregulation during a 30-minute running time trial in 35°C heat.

Recently, Grgic (2018) discussed the concept of responders and non-responders to caffeine supplementation highlighting the importance of the repeatability of results. However, the number of studies that have investigated this idea by repeating the same time-trial performance test multiple times with the same caffeine dose is sparse (Astorino et al., 2012; Del Coso et al., 2019). Furthermore, studies have shown that differences in the CYP1A2 genotype may account for some of the variation in time-trial performance (Guest et al., 2018). Thus, the current study aims to identify whether the effects of moderate caffeine supplementation (5 mg/kg) on time-trial performance are repeatable to aid the identification of responders and non-responders. Additionally, the study aims to determine if the CYP1A2 genotype may explain any of the variability in time-trial performance in trained male cyclists.

Introduction: The caffeine is used in the treatment for apnea of prematurity and it has several positive effects in the neurodevelopment of preterm babies. There are innumerable observational studies suggesting that initiating caffeine in the first hours of life may offer more benefits in the reduction of the necessity of intubation and in ventilation time. It is necessary to expand further research on the best time to start caffeine, which may improve the quality of care for premature infants. Objective: To evaluate the benefits of caffeine administration in the first two hours of life compared to administration at 24 hours of life in premature patients on noninvasive mechanical ventilation with birth weights less than 1250 grams. Methodology: Preterm newborn patients with birth weight \< 1250 grams born at Hospital de Clínicas de Porto Alegre who are not intubated in the delivery room will be included. Patients will be randomized into two groups. One arm of the study will receive caffeine at 2 hours of age and the other arm will receive caffeine at 24 hours of age (control). Patients in the control group will receive 0.9% SF at 2 hours of life in order to keep the study blinded. The following outcomes will be evaluated: need for intubation, time on invasive and non-invasive mechanical ventilation, BPD, necrotizing enterocolitis, need for ROP treatment, PDA with hemodynamic repercussions, peri-intraventricular hemorrhage, leukomalacia and death. The sample size calculation is 50 patients, 25 in each arm. Expected Results: It is expected to find a 43% reduction in the need for intubation in preterm infants who receive caffeine in the first two hours of life compared to administration at 24 hours of life. It is also expected to find a reduction in mechanical ventilation time, in addition to a possible reduction in negative outcomes associated with prematurity.

The aim of the study is to investigate the acute and chronic effects of a supplement containing Caffeine, Vitamins, Minerals and Botanical extracts on cognitive function, sleep and wellbeing, in healthy volunteers. The study will follow a randomised, double-blind, placebo-controlled, crossover design. Participants will receive both treatments, and both study arms will include an acute testing visit (day 1) and a chronic testing visit (day 29). The active treatment contains a blend of 120mg caffeine, vitamins, minerals and botanical extracts and the matched placebo treatment contains marigold extract and brown rice flour. The trial will use computerised cognitive tasks, administered via COMPASS software (Northumbria University, UK), online cognitive assessments via Cognimapp and self-reported questionnaires and sleep diary, as measures of the outcome variables. 90 participants will participate, aged 18-75, and self-ported as being in good health. Participants will be randomly allocated to a treatment order and will be supplied with either the active treatment or the placebo whilst visiting the research centre for the acute testing visits. Participants will take the treatment home to consume daily for the duration of the supplementation period. Participants will record the time of taking treatment each day in a treatment diary which will be returned to the research centre, along with any unused treatment, at each chronic testing visit.

This research study aims to determine whether and how caffeine intake affects learning process through reward feedback compared to placebo. The data acquired from this study would improve our understanding on the consequence and mechanism of caffeine intake in the aspect of learning process. Participants will perform a reinforcement learning task (i.e. Probabilistic Selection Task) and a motor inhibition task (i.e. Go/NoGo task) in a brain scan. The scan will be done with the Siemens Biograph mMR positron emission tomography (PET)/ magnetic resonance imaging (MRI) 3 Tesla scanner. The PET allows us to see the changes in the "reward signals" - dopamine - in the brain using a radioactive dye called \[11C\]Raclopride. The MRI, on the other hand, enables us to take detailed pictures of the brain activities during cognitive tasks using a high-powered magnet. Reviewing these pictures will help us understand the influence of caffeine on reward signals and brain activities during the learning process.