title: Training and oxygen conductance in the elderly. II. The cardiovascular system.
abstract: CO2 rebreathing measurements of cardiac output have been made in 8 men and 7 women aged 60--76 years, before and immediately after participation in an 11-week endurance training programme. Initial values showed a lower heart rate than in younger subjects at a given percentage of maximum oxygen intake. Stroke volume decreased slightly over the range of 40--80% of maximum oxygen intake. Relative to younger subjects, metabolic needs were thus met to a larger extent by a widening of arterio-venous oxygen difference and redistribution of blood flow. Over the period of observation, training induced a decrease in heart rate and cardiac output at a given sub-maximum work load, with no change in stroke volume or arterio-venous oxygen difference.
mesh_terms: D000367:Age Factors; D000368:Aged; D002302:Cardiac Output; D002320:Cardiovascular Physiological Phenomena; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D010100:Oxygen / Q000097:blood*; D010806:Physical Education and Training; D012119:Respiration; D012737:Sex Factors; D013318:Stroke Volume
chemical_list: D010100:Oxygen