Biomaterial Database

Circulatory responses to progressive exercise: insights from positional differences. 2003

T Rowland, and A Garrison, and A Delulio

Department of Pediatrics, Baystate Medical Center, Springfield, MA 01199, USA. thomas.rowland@bhs.org

The influence of body position on cardiac responses to progressive exercise was examined in 13 healthy circumpubertal boys. The subjects (mean age 12.5 +/- 1.4 y) performed a progressive cycle test with an identical protocol in the sitting and supine positions. Stroke volume and left ventricular dimensions were assessed with Doppler and two-dimensional echocardiography, respectively. During supine exercise, no changes were seen in stroke volume or left ventricular preload (end-diastolic dimension) with increasing exercise intensity. At rest, mean values for stroke volume and cardiac output were 16.4 % and 27.1 % lower, respectively, with subjects upright compared to supine. With upright exercise these variables rose to become insignificantly different than supine values. Stroke volume while cycling upright rose by 29 % by the second workload but remained stable at higher work intensities. The initial increase in stroke volume observed only when cycling upright presumably reflects mobilization of dependent blood in the lower extremities. The mechanisms governing cardiac responses to exercise when supine and upright are otherwise identical.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D001775	Blood Circulation	The movement of the BLOOD as it is pumped through the CARDIOVASCULAR SYSTEM.	Blood Flow,Circulation, Blood,Blood Flows,Flow, Blood
D002302	Cardiac Output	The volume of BLOOD passing through the HEART per unit of time. It is usually expressed as liters (volume) per minute so as not to be confused with STROKE VOLUME (volume per beat).	Cardiac Outputs,Output, Cardiac,Outputs, Cardiac
D006112	Gravitation	Acceleration produced by the mutual attraction of two masses, and of magnitude inversely proportional to the square of the distance between the two centers of mass. It is also the force imparted by the earth, moon, or a planet to an object near its surface. (From NASA Thesaurus, 1988)	G Force,Gravistimulation,Gravity,Force, G,G Forces,Gravities
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000293	Adolescent	A person 13 to 18 years of age.	Adolescence,Youth,Adolescents,Adolescents, Female,Adolescents, Male,Teenagers,Teens,Adolescent, Female,Adolescent, Male,Female Adolescent,Female Adolescents,Male Adolescent,Male Adolescents,Teen,Teenager,Youths
D013318	Stroke Volume	The amount of BLOOD pumped out of the HEART per beat, not to be confused with cardiac output (volume/time). It is calculated as the difference between the end-diastolic volume and the end-systolic volume.	Ventricular Ejection Fraction,Ventricular End-Diastolic Volume,Ventricular End-Systolic Volume,Ejection Fraction, Ventricular,Ejection Fractions, Ventricular,End-Diastolic Volume, Ventricular,End-Diastolic Volumes, Ventricular,End-Systolic Volume, Ventricular,End-Systolic Volumes, Ventricular,Fraction, Ventricular Ejection,Fractions, Ventricular Ejection,Stroke Volumes,Ventricular Ejection Fractions,Ventricular End Diastolic Volume,Ventricular End Systolic Volume,Ventricular End-Diastolic Volumes,Ventricular End-Systolic Volumes,Volume, Stroke,Volume, Ventricular End-Diastolic,Volume, Ventricular End-Systolic,Volumes, Stroke,Volumes, Ventricular End-Diastolic,Volumes, Ventricular End-Systolic
D015150	Echocardiography, Doppler	Measurement of intracardiac blood flow using an M-mode and/or two-dimensional (2-D) echocardiogram while simultaneously recording the spectrum of the audible Doppler signal (e.g., velocity, direction, amplitude, intensity, timing) reflected from the moving column of red blood cells.	Doppler Echocardiography,Echocardiography, Continuous Doppler,Echocardiography, Two-Dimensional Doppler,2-D Doppler Echocardiography,2D Doppler Echocardiography,Continuous Doppler Echocardiography,Doppler Echocardiography, 2-D,Doppler Echocardiography, 2D,Doppler Echocardiography, Continuous,Doppler Echocardiography, Two-Dimensional,Echocardiography, 2-D Doppler,Echocardiography, 2D Doppler,Two-Dimensional Doppler Echocardiography,2 D Doppler Echocardiography,Doppler Echocardiography, 2 D,Doppler Echocardiography, Two Dimensional,Echocardiography, 2 D Doppler,Echocardiography, Two Dimensional Doppler,Two Dimensional Doppler Echocardiography
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
D016277	Ventricular Function, Left	The hemodynamic and electrophysiological action of the left HEART VENTRICLE. Its measurement is an important aspect of the clinical evaluation of patients with heart disease to determine the effects of the disease on cardiac performance.	Left Ventricular Function,Function, Left Ventricular,Functions, Left Ventricular,Left Ventricular Functions,Ventricular Functions, Left