Search results for "Caffeine"
showing 10 items of 118 documents
From the Big Five to the General Factor of Personality: a Dynamic Approach
2014
AbstractAn integrating and dynamic model of personality that allows predicting the response of the basic factors of personality, such as the Big Five Factors (B5F) or the general factor of personality (GFP) to acute doses of drug is presented in this paper. Personality has a dynamic nature, i.e., as a consequence of a stimulus, the GFP dynamics as well as each one of the B5F of personality dynamics can be explained by the same model (a system of three coupled differential equations). From this invariance hypothesis, a partial differential equation, whose solution relates the GFP with each one of the B5F, is deduced. From this dynamic approach, a co-evolution of the GFP and each one of the B…
Metabolomic Changes after Coffee Consumption: New Paths on the Block
2021
Scope Several studies suggest that regular coffee consumption may help preventing chronic diseases, but the impact of daily intake and the contribution of coffee metabolites in disease prevention are still unclear. The present study aimed at evaluating whether and how different patterns of coffee intake (one cup of espresso coffee/day, three cups of espresso coffee/day, one cup of espresso coffee/day and two cocoa-based products containing coffee two times per day) might impact endogenous molecular pathways. Methods and results A three-arm, randomized, cross-over trial was performed in 21 healthy volunteers who consumed each treatment for one month. Urine samples were collected to perform u…
Methylphenidate, modafinil, and caffeine for cognitive enhancement in chess: A double-blind, randomised controlled trial.
2017
Stimulants and caffeine have been proposed for cognitive enhancement by healthy subjects. This study investigated whether performance in chess - a competitive mind game requiring highly complex cognitive skills - can be enhanced by methylphenidate, modafinil or caffeine. In a phase IV, randomized, double-blind, placebo-controlled trial, 39 male chess players received 2×200mg modafinil, 2×20mg methylphenidate, and 2×200mg caffeine or placebo in a 4×4 crossover design. They played twenty 15-minute games during two sessions against a chess program (Fritz 12; adapted to players' strength) and completed several neuropsychological tests. Marked substance effects were observed since all three subs…
Cardiovascular prevention and at-risk behaviours in a large population of amateur rugby players.
2019
Background and aim We aimed to investigate cardiovascular risk factors and health behaviours prospectively in a large population of French amateur rugby players. Methods An anonymous questionnaire was displayed to rugby players aged over 12 years enrolled in the 2014–2015 French amateur rugby championship from the Burgundy region ( n = 5140). Questions addressed awareness on: (a) cardiovascular prevention; (b) tobacco, alcohol and highly caffeinated beverages consumption; and (c) adherence to prevention guidelines (ECG checks, training in basic life support, avoidance of sports practice during fever/infectious episodes). Results Among the 640 participants who completed the questionnaires, m…
Dynamics of the General Factor of Personality in Response to a Single Dose of Caffeine
2011
General Factor of Personality (GFP) research is an emergent field in personality research. This paper uses a theoretical mathematical model to predict the short-term effects of a dose of a stimulant drug on GFP and reports the results of an experiment showing how caffeine achieves this. This study considers the General Factor of Personality Questionnaire (GFPQ) a good psychometric approach to assess GFP. The GFP dynamic mechanism of change is based on the Unique Trait Personality Theory (UTPT). This theory proposes the existence of GFP which occupies the apex of the hierarchy of personality, and extends from an impulsiveness-and-aggressiveness pole (approach tendency) to an anxiety-andintro…
Effect of caffeine on simulator flight performance in sleep-deprived military pilot students.
2007
Caffeine has been suggested to act as a countermeasure against fatigue in military operations. In this randomized, double-blind, placebo-controlled study, the effect of caffeine on simulator flight performance was examined in 13 military pilots during 37 hours of sleep deprivation. Each subject performed a flight mission in simulator four times. The subjects received either a placebo (six subjects) or 200 mg of caffeine (seven subjects) 1 hour before the simulated flights. A moderate 200 mg intake of caffeine was associated with higher axillary temperatures, but it did not affect subjectively assessed sleepiness. Flight performance was similar in both groups during the four rounds flown und…
The Phenomenon of a High Triglyceride Response to an Oral Lipid Load in Healthy Subjects and Its Link to the Metabolic Syndrome
1993
Excessive postprandial triglyceride (TG) responses despite normal fasting TG levels have been described in single cases within small groups of healthy subjects and in patients with obesity or precocious atherosclerosis, known to be associated with high insulin fasting levels. To clarify this association, fasting and postprandial TG and insulin levels were studied in 113 healthy young (25.7 +/- 2.6 years), normal weight (body mass index 20.8 +/- 2.3 kg/m2) male subjects who were selected from among 117 subjects on the basis of TG fasting levels200 mg/dl. After a 12-hour fast a standardized liquid lipid load was administered containing 58 g mainly saturated fat and 1,017 kcal energy. Both fas…
Acute effects of coffee on QT interval in healthy subjects
2011
Abstract The coronary endothelial function is recognized to have an important role in the physiology of the diastolic ventricular relaxation, a phase of the heart cycle that influences the electrocardiographic QT interval. Endothelial function is investigated in vivo by flow mediated dilation (FMD) in the brachial artery and has proven to be a strong predictor of both coronary endothelial function and cardiovascular events. It has been reported that coffee acutely induces FMD changes. In particular, the brachial artery FMD seems to decrease after caffeinated coffee (CC) and to increase after decaffeinated coffee (DC) ingestion. Since the cardiovascular effects of coffee are still a debated …
Dose-dependent effects of decaffeinated coffee on endothelial function in healthy subjects
2009
ackground/Objectives: Coffee is known to contain antioxidant substances whose effects may be blunted because of caffeine that may unfavorably affect the cardiovascular system. This study was designed to investigate the acute dose-dependent effects of decaffeinated coffee (DC) on endothelial function measured by the brachial artery flow-mediated dilation (FMD). Subjects/Methods: A total of 15 (8 men and 7 women) healthy nonobese subjects underwent a single-blind, crossover study. Subjects ingested one and two cups of decaffeinated Italian espresso coffee in random order at 5- to 7-day intervals. Results: In the hour following the ingestion of two cups of DC, FMD increased (mean±s.e.m.): 0 mi…
Night-rest urinary catecholamine excretion in relation to aspects of free time, work and background data in a teacher group
1991
Free time, work and background data were related to night-rest catecholamine excretion rates in a teacher group (n = 137) during an autumn term. The explained interindividual variance increased slightly towards the end of the term. Adrenaline excretion was predicted better than noradrenaline, notedly by coffee consumption, amount of physical activity, and subjective stress feelings which explained 16% of the variance in adrenaline excretion during night rest. However, the results indicated that the differences in catecholamine excretion during night rest remained mostly unpredictable.