The effect of waist/torso weights on the physiological responses to submaximal exercise

The purpose of this study was to determine the efficacy of using a weighted belt and vest to increase energy cost of walking and to investigate the effects on cardiorespiratory function. Fourteen moderately trained males completed three submaximal treadmill exercises while walking at 3.7 mph at a grade which elicited an intensity of 50% peak VO2 (determined from an unweighted graded exercise test). Each subject walked for 36 minutes while carrying no weight (C), 5 Kg (E-5) and 10 Kg (E-10) on the waist and torso. Oxygen uptake (VO2), heart rate (HR), systolic blood pressure (SBP), rate pressure product (RPP), and the respiratory exchange ratio (R) were measured. Significant differences were found between the steady rate means of all variables (p0.05). The means of VO2 (24.6 ±4.4, 26.5 ±5.1, and 27.2 ±4.3 ml*kg-1 ; C, E-5 E-10, respectively), HR (128 ±14, 139 ±23, 140 ±16 bpm), SBP (158 ±12, 165 ±13, 168 ±13 mm Hg), RPP (20235 ±3039, 22927 ±4853, 23515 ±4071 beats*mmHg*min-1), and R (0.849 ±0.025, 0.896 ±.041, 0.883 ±.035) were highest in the weighted conditions. The differences were found to be between C and E-5 and C and E- 10. No differences were found between the weighted conditions. Myocardial oxygen consumption,MVO2 , as estimated by RPP, had a greater magnitude of change in the weighted conditions (13.3% 16.2 % change, E-5 E-10, respectively) than did from the total body oxygen consumption, VO2 (7.7% 10.6% change, E-5 E-10, respectively). This data suggests that weights of 5 Kg and 10 Kg carried on the waist/torso can be effective in increasing the energy cost as well as the cardiac cost of walking exercise.