Effect of Physical Training on Circulation during Prolonged Severe Exercise1

Abstract Before, and after 22 weeks of physical training, oxygen uptake, heart rate and cardiac output (dye dilution technique) were measured in 7 male subjects (22 to 26 years old) during pro longed severe exercise (60 min on 75 % of the individual's maximal oxygen uptake) and during exhausting work loads of about 5 min duration. Maximal oxygen uptake increased from 3.41 l/min (48.0 mllkg per min) before to 3.64 I/min (52.0 ml/kg per min) after the training (p<0.05). Maximal heart rate decreased from 201 beats/min before to 194 beats/min after the training (p<0.05). During the 1 hr work period after the training the stroke volume and mean blood pressure became higher (p<0.05) and (a—v)O 2 diff. lower (p<0.05) than before the training. From the 5th to the 60th min of the prolonged work the heart rate increased about 20 beatslmin before as well as after the training.