Cardiopulmonary and Metabolic Responses to Additional Weights on Ankle and Wrist during Walking in Healthy College Students

Abstract

Carrying weights in the hands and ankles is an alternative method of increasing exercise intensity in walking for individuals who cannot jog or run at higher speeds and may increase energy expenditure. However, previous findings were inconsistent regarding cardiopulmonary and metabolic responses to additional weights on the ankles and wrists. PURPOSE The purpose of our study is to determine the effects of additional weights on the ankles and wrists in relation to cardiopulmonary and metabolic responses during walking exercise in young and healthy college students. It was hypothesized that there is no difference in oxygen consumption, substrate utilization, and total caloric expenditure among no weight, ankle weight, and wrist weight conditions during walking exercise on the treadmill. METHODS Sixteen relatively healthy and young college individuals (BMI ≥ 18 kg/m2 and ≤25 kg/m2 and 18-30 yrs.) were recruited. Each participant visited 5 times. The first visit consisted of a maximal aerobic fitness test (VO2peak). The second visit consisted of finding the participant's treadmill speed that correlates with 40% of the VO2peak. The third visit consisted of walking for thirty minutes at 40% of their VO2peak without any weights added. The fourth and fifth visits consisted of the same procedure as the third visit, only with the additional weight (1.5% of body weight) added to each limb on either the ankles or wrists. The order in which the ankle and wrist trials occur was randomly assigned. Cardiopulmonary and metabolic responses were measured via indirect calorimetry. One-way RM ANOVA was used to determine differences in oxygen consumption (VO2), heart rate (HR), fat and carbohydrate (CHO) utilization, and total energy expenditure between walking conditions. RESULTS VO2 was lowest for no weight followed by wrist and ankle weight conditions, respectively (16.89±0.47, 17.86±0.48, and 19.05±0.68 ml/kg/min). Also, VO2 was significantly higher in ankle weight than wrist weight condition. HRs were also lowest for no weight followed by wrist and ankle weight conditions, respectively (120.4±1.9, 125.9±2.7, and 130.2±2.4 bpm). HRs were significantly higher in ankle weight than wrist weight condition. The rate of total EE (kcal/min) during walking was significantly increased with additional weights on the ankle (5.88±0.34 kcal/min) and the wrist (5.38±0.33 kcal/min), compared to no weights added (5.18±0.28kcal/min) and the rate of total EE was significantly higher in ankle weight than wrist weight condition. However, the rate of fat utilization was not different among no weight, ankle weight, and wrist weight conditions during walking. CONCLUSION Our findings demonstrated that the cardiopulmonary and metabolic responses to additional weights on the ankles and wrists were significantly greater than no weight added during walking exercise. Moreover, the VO2, HRs and total EE during the moderate intensity of walking were higher when additional weights were added especially on the ankle, compared to the wrist location. Therefore, the findings of our study may provide that carrying weights in the hands and/or ankles is an alternative walking method of increasing exercise intensity, thereby elevating caloric expenditure and maintaining healthy body weights in young individuals.