Biomaterial Database

Effects of caffeine on physiological responses to exercise in young boys and girls. 2006

Kenneth R Turley, and Jonathan W Gerst

Human Performance Laboratory, Department of Kinesiology, Harding University, Searcy, AR, USA. krturley@harding.edu

OBJECTIVE To describe the influence of caffeine on physiological responses to exercise in young children and determine whether sex differences in these responses exist. METHODS Twenty-six healthy 7- to 9-yr-old boys and 26 healthy 7- to 9-yr-old girls volunteered to participate in a double-blind, randomized, double crossover study design. Each child randomly received both the placebo (PL) and caffeinated (5 mg x kg(-1)) drink (CAF) twice each on four separate days. Following a 1-h wash-in period and resting measures, each child rode a cycle ergometer at 25 and then 50 W for 8 min each, while HR, blood pressure (BP), and oxygen consumption (VO2) were measured. RESULTS HR (bpm) was significantly (P < 0.05) lower at rest and at 25 and 50 W in CAF versus PL in both boys and girls. Diastolic BP (mm Hg) was significantly (P </= 0.05) higher at rest, 25 W in both boys and girls, and at 50 W in boys, in CAF versus PL. Systolic BP (mm Hg) was significantly (P </= 0.05) higher at rest in both boys and girls, at 25 W in boys, and at 50 W in girls. During exercise, VO2 (L x min(-1) or mL x kg(-1) x min(-1)) and RER were not different in CAF versus PL in either boys or girls. CONCLUSIONS A moderate dose of caffeine (5 mg.kg) does not affect metabolism (VO2 or RER) in young children at low-moderate intensities of exercise. However, CAF causes a significantly lower HR (bpm) and higher BP (mm Hg) in both young boys and girls.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D010829	Physiological Phenomena	The functions and properties of living organisms, including both the physical and chemical factors and processes, supporting life in single- or multi-cell organisms from their origin through the progression of life.	Physiological Processes,Physiological Concepts,Physiological Phenomenon,Physiological Process,Concept, Physiological,Concepts, Physiological,Phenomena, Physiological,Phenomenas, Physiological,Phenomenon, Physiological,Physiological Concept,Process, Physiological,Processes, Physiological
D002110	Caffeine	A methylxanthine naturally occurring in some beverages and also used as a pharmacological agent. Caffeine's most notable pharmacological effect is as a central nervous system stimulant, increasing alertness and producing agitation. It also relaxes SMOOTH MUSCLE, stimulates CARDIAC MUSCLE, stimulates DIURESIS, and appears to be useful in the treatment of some types of headache. Several cellular actions of caffeine have been observed, but it is not entirely clear how each contributes to its pharmacological profile. Among the most important are inhibition of cyclic nucleotide PHOSPHODIESTERASES, antagonism of ADENOSINE RECEPTORS, and modulation of intracellular calcium handling.	1,3,7-Trimethylxanthine,Caffedrine,Coffeinum N,Coffeinum Purrum,Dexitac,Durvitan,No Doz,Percoffedrinol N,Percutaféine,Quick-Pep,Vivarin,Quick Pep,QuickPep
D002648	Child	A person 6 to 12 years of age. An individual 2 to 5 years old is CHILD, PRESCHOOL.	Children
D004311	Double-Blind Method	A method of studying a drug or procedure in which both the subjects and investigators are kept unaware of who is actually getting which specific treatment.	Double-Masked Study,Double-Blind Study,Double-Masked Method,Double Blind Method,Double Blind Study,Double Masked Method,Double Masked Study,Double-Blind Methods,Double-Blind Studies,Double-Masked Methods,Double-Masked Studies,Method, Double-Blind,Method, Double-Masked,Methods, Double-Blind,Methods, Double-Masked,Studies, Double-Blind,Studies, Double-Masked,Study, Double-Blind,Study, Double-Masked
D005260	Female		Females
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D012737	Sex Factors	Maleness or femaleness as a constituent element or influence contributing to the production of a result. It may be applicable to the cause or effect of a circumstance. It is used with human or animal concepts but should be differentiated from SEX CHARACTERISTICS, anatomical or physiological manifestations of sex, and from SEX DISTRIBUTION, the number of males and females in given circumstances.	Factor, Sex,Factors, Sex,Sex Factor
D014481	United States	A country in NORTH AMERICA between CANADA and MEXICO.
D015444	Exercise	Physical activity which is usually regular and done with the intention of improving or maintaining PHYSICAL FITNESS or HEALTH. Contrast with PHYSICAL EXERTION which is concerned largely with the physiologic and metabolic response to energy expenditure.	Aerobic Exercise,Exercise, Aerobic,Exercise, Isometric,Exercise, Physical,Isometric Exercise,Physical Activity,Acute Exercise,Exercise Training,Activities, Physical,Activity, Physical,Acute Exercises,Aerobic Exercises,Exercise Trainings,Exercise, Acute,Exercises,Exercises, Acute,Exercises, Aerobic,Exercises, Isometric,Exercises, Physical,Isometric Exercises,Physical Activities,Physical Exercise,Physical Exercises,Training, Exercise,Trainings, Exercise