Biomaterial Database

Thermoregulatory effects of caffeine ingestion during submaximal exercise in men. 1998

N Dunagan, and J E Greenleaf, and C J Cisar

Exercise Physiology Laboratory, San Jose State University, CA, USA.

BACKGROUND The exclusive effect of caffeine ingestion on exercise thermoregulation is unclear; data indicate that caffeine may have a positive effect, a negative effect, or no effect. METHODS Rectal (TRE) and mean skin (TSK) temperatures, skin heat conductance (HSK), and sweat rate (MSW) were measured during 30 min of rest and subsequent 70 min of submaximal cycle-ergometer exercise (67% VO2PEAK) in 11 aerobically conditioned men (mean +/- SD 29 +/- 6 yr, 49 +/- 6 mL x min(-1) x kg(-1) VO2PEAK) under two conditions: a caffeine (10 mg x kg(-1) ingestion (CI) session and a noncaffeine ingestion (NCI) control session. RESULTS There were no significant differences in physiological or thermoregulatory parameters during exercise: X (+/-SE) end exercise levels for the NCI and CI sessions, respectively, were VO2 = 2.50 +/- 0.09 vs. 2.55 +/- 0.09 L x min(-1); heart rate = 145 +/- 7 vs. 145 +/- 5 bpm; HSK = 30 +/- 3 vs. 28 +/- 3 kcal x m(-2) x h(-1) x degrees C(-1); MSW = 393 +/- 35 vs. 378 +/- 36 g x m(-2) x h(-1); and TRE = 38.3 +/- 0.2 vs. 38.4 +/- 0.1 degrees C. Control TSK was lower than that for CI by 0.4 to 0.5 degrees C at rest and during exercise. CONCLUSIONS Ingestion of a high level (10 mg x kg(-1) of caffeine has no effect on skin heat conductance, sweating, or the rate of increase and final level of rectal temperature during moderate, submaximal leg exercise.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D010101	Oxygen Consumption	The rate at which oxygen is used by a tissue; microliters of oxygen STPD used per milligram of tissue per hour; the rate at which oxygen enters the blood from alveolar gas, equal in the steady state to the consumption of oxygen by tissue metabolism throughout the body. (Stedman, 25th ed, p346)	Consumption, Oxygen,Consumptions, Oxygen,Oxygen Consumptions
D012007	Rectum	The distal segment of the LARGE INTESTINE, between the SIGMOID COLON and the ANAL CANAL.	Rectums
D012146	Rest	Freedom from activity.	Rests
D001831	Body Temperature	The measure of the level of heat of a human or animal.	Organ Temperature,Body Temperatures,Organ Temperatures,Temperature, Body,Temperature, Organ,Temperatures, Body,Temperatures, Organ
D001833	Body Temperature Regulation	The processes of heating and cooling that an organism uses to control its temperature.	Heat Loss,Thermoregulation,Regulation, Body Temperature,Temperature Regulation, Body,Body Temperature Regulations,Heat Losses,Loss, Heat,Losses, Heat,Regulations, Body Temperature,Temperature Regulations, Body,Thermoregulations
D001835	Body Weight	The mass or quantity of heaviness of an individual. It is expressed by units of pounds or kilograms.	Body Weights,Weight, Body,Weights, Body
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
D005080	Exercise Test	Controlled physical activity which is performed in order to allow assessment of physiological functions, particularly cardiovascular and pulmonary, but also aerobic capacity. Maximal (most intense) exercise is usually required but submaximal exercise is also used.	Arm Ergometry Test,Bicycle Ergometry Test,Cardiopulmonary Exercise Testing,Exercise Testing,Step Test,Stress Test,Treadmill Test,Cardiopulmonary Exercise Test,EuroFit Tests,Eurofit Test Battery,European Fitness Testing Battery,Fitness Testing,Physical Fitness Testing,Arm Ergometry Tests,Bicycle Ergometry Tests,Cardiopulmonary Exercise Tests,Ergometry Test, Arm,Ergometry Test, Bicycle,Ergometry Tests, Arm,Ergometry Tests, Bicycle,EuroFit Test,Eurofit Test Batteries,Exercise Test, Cardiopulmonary,Exercise Testing, Cardiopulmonary,Exercise Tests,Exercise Tests, Cardiopulmonary,Fitness Testing, Physical,Fitness Testings,Step Tests,Stress Tests,Test Battery, Eurofit,Test, Arm Ergometry,Test, Bicycle Ergometry,Test, Cardiopulmonary Exercise,Test, EuroFit,Test, Exercise,Test, Step,Test, Stress,Test, Treadmill,Testing, Cardiopulmonary Exercise,Testing, Exercise,Testing, Fitness,Testing, Physical Fitness,Tests, Arm Ergometry,Tests, Bicycle Ergometry,Tests, Cardiopulmonary Exercise,Tests, EuroFit,Tests, Exercise,Tests, Step,Tests, Stress,Tests, Treadmill,Treadmill Tests
D006339	Heart Rate	The number of times the HEART VENTRICLES contract per unit of time, usually per minute.	Cardiac Rate,Chronotropism, Cardiac,Heart Rate Control,Heartbeat,Pulse Rate,Cardiac Chronotropy,Cardiac Chronotropism,Cardiac Rates,Chronotropy, Cardiac,Control, Heart Rate,Heart Rates,Heartbeats,Pulse Rates,Rate Control, Heart,Rate, Cardiac,Rate, Heart,Rate, Pulse