SAGIV, M., D. BEN-SIRA, A. SAGIV, G. WERBER, and A. ROTSTEIN. Left ventricular responses during prolonged treadmill walking with heavy load carriage. Med. Sci. Sports Exerc., Vol. 26, No. 3, pp. 285-288, 1994. This study examined with metabolic cart and echo-Doppler the influence of different load carriage 4 h of treadmill walking on left ventricular systolic function, hemodynamics, and cardiovascular responses. Twenty-six aerobically well-trained male subjects (VO2max = 65.2 +/- 5 ml[middle dot]kg-1) volunteered for this study. Subjects carried a load of 38 kg during one session and a load of 50 kg during the other session. Following the 4-h exercise in each session, significant (P <0.05) differences were noted between the 38-kg and 50-kg workloads with regard to VO2; 14.4 +/- 2 and 19 +/- 5 ml[middle dot]kg-1; heart rate: 104 +/- 14 and 125 +/- 17 beats[middle dot]min-1; diastolic blood pressure: 69 +/- 4 and 79 +/- 4 mm Hg; and rate pressure product 140.4 +/- 15 and 173.8 +/- 20 index[middle dot]10-2; respectively. No significant differences were noted between the workloads in regard to systolic blood pressure, perceived exertion rating, and aortic valve Doppler indices. We concluded that during prolonged treadmill walking in well-trained young subjects, the additional load above 50% up to 66% of body weight did not change the steady state of left ventricular systolic function, hemodynamics, and cardiovascular responses throughout the course of the 240 min of effort.
(C)1994The American College of Sports Medicine