High-intensity endurance training in 20- to 30- and 60- to 70-yr-old healthy men.
Factors contributing to maximal incremental and short-term exercise capacity were measured before and after 12 wk of high-intensity endurance training in 12 old (60-70 yr) and 10 young (20-30 yr) sedentary healthy males. Peak O2 uptake in incremental cycle ergometer exercise increased from 1.60 +/- 0.073 to 2.21 +/- 0.073 (SE) l/min (38% increase) in the old subjects and from 2.54 +/- 0.141 to 3.26 +/- 0.181 l/min (29%) in the young subjects. Peak cardiac output, estimated by extrapolation from a series of submaximal measurements by the CO2 rebreathing method, increased by 30% (from 12.7 to 16.5 l/min) in the old subjects, associated with a 6% increase (from 126 to 135 ml/l) in arteriovenous O2 difference; in the young subjects there were equal 14% increases in both variables (18.0 to 20.5 l/min and 140 to 159 ml/l, respectively). Submaximal mean arterial pressure and cardiac output were lower posttraining in the old subjects; total vascular conductance and cardiac stroke volume increased. Although peak power at the start of a short-term maximal isokinetic test did not change, total work accomplished in 30 s at a pedaling frequency of 110 revolutions/min increased in both groups, from 11.2 to 12.6 kJ and from 15.7 to 16.9 kJ in the old and young, respectively; fatigue during the 30-s test was less, and postexercise plasma lactate concentrations were lower. In older subjects, increases in aerobic power after high-intensity endurance training are at least as large as in younger subjects and are associated with increases in vascular conductance, maximal cardiac output, and stroke volume.
Makrides
L
L
Ambrose Cardiorespiratory Unit, McMaster University Health Sciences Centre, Hamilton, Ontario, Canada.
Heigenhauser
G J
GJ
Jones
N L
NL
D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D015308:Anaerobic Threshold; D002302:Cardiac Output; D005080:Exercise Test; D006801:Humans; D008297:Male; D008875:Middle Aged; D009132:Muscles / Q000502:physiology; D010101:Oxygen Consumption; D010806:Physical Education and Training; D010807:Physical Endurance; D012016:Reference Values; D013318:Stroke Volume