Evaluation of the relationship between venous function and post exercise oxygen consumption recovery kinetics

Excess post-exercise oxygen consumption (EPOC) has been attributed to metabolic, hemodynamic, neuroendocrine, and pulmonary factors. In one particular study, Barclay (J Appl Physiol 1986;61(3):1084-90) suggested that a lower rate of fatigue and hyperperfusion following a bout of exercise was due to a mechanism other than increased oxygen and substrate delivery. Interestingly, few studies have examined the influence of venous function on EPOC. The purpose of this study was to examine the relationship between measures of vascular function and EPOC. Measures of vascular function and VO2 recovery kinetics were examined in 20 individuals [age=22+2.41 yrs]. Nondominant forearm arterial inflow, venous capacitance and venous outflow were evaluated at rest and after 5 minutes of upper arm occlusion, using strain gauge plethysmography. VO2 recovery kinetics was assessed using gas exchange analysis following a six-minute constant work rate protocol at 60 percent of VO2peak, on a cycle ergometer. The average VO2peak was 33.48+8.22 ml/kg/min (Range: 18.7 to 46.1 ml/kg/min). Recovery half-time (T1/2VO2) and Tao were 17.01+3.51 seconds and 54.45+11.28 seconds, respectively. Resting inflow was 2.77+1.51 ml/100ml/min, reactive hyperemic blood flow was 17.72+3.65 ml/100ml/min, venous capacitance was 2.86+0.72 percent, and venous outflow was 34.19+10.03 ml/100ml/min. Bivariate correlations revealed significant associations between T1/2VO2 and the reactive hyperemic response (r=-0.48, p=0.03) and T1/2VO2 and venous outflow post-occlusion (r=-0.50, p=0.02). In conclusion, these findings suggest an important role of both the arterial and venous circulation on EPOC

Influence of venous emptying on the reactive hyperemic blood flow response

BACKGROUND: Previous research indicates that venous emptying serves as a stimulus for vasodilation in the human forearm. This suggests the importance of recognizing the potential influence of venous volume on reactive hyperemic blood flow (RHBF) following occlusion. The purpose of this study was to examine the influence of venous emptying on forearm vascular function. METHODS: Forearm RHBF, venous capacitance and venous outflow were examined in 35 individuals (age = 22 ± 2 years), using mercury in-Silastic strain gauge plethysmography, at rest and following five minutes of upper arm occlusion using standard procedures (Control). In addition, the same measures were obtained following five minutes of upper arm occlusion preceded by two minutes of passive arm elevation (Pre-elevation). RESULTS: Average resting arterial inflow was 2.42 ± 1.11 ml·100 ml(-1)·min(-1). RHBF and venous capacitance were significantly greater during Pre-elevation compared to Control (RHBF; Pre-elevation: 23.76 ± 5.95 ml·100 ml(-1 )·min(-1 )vs. Control: 19.33 ± 4.50; p = 0.001), (venous capacitance; Pre-elevation: 2.74 ± 0.89 % vs. Control: 2.19 ± 0.97, p = 0.001). Venous outflow did not differ between the two conditions. CONCLUSION: Venous emptying prior to upper arm occlusion results in a significant greater RHBF response and venous capacitance. Recognition of the influence of venous volume on RHBF is particularly important in studies focusing on arterial inflow, and also provides further evidence for the interplay between the venous and arterial system

Association of Venous Function and Post-Exercise Oxygen Consumption

International Journal of Exercise Science 6(1) : 63-73, 2013. Excess post-exercise oxygen consumption (EPOC) has been attributed to metabolic, hemodynamic, neuroendocrine, and pulmonary factors. Interestingly, few studies have examined the role of venous system on EPOC. The purpose of this study was to examine the relationship between measures of vascular function and EPOC. Measures of vascular function and VO2 recovery kinetics were examined in 20 individuals [age=22+2.41 yrs]. Nondominant forearm arterial inflow, venous capacitance and venous outflow were evaluated at rest and after 5 minutes of upper arm occlusion, using strain gauge plethysmography. VO2 recovery kinetics was assessed using gas exchange analysis following a six-minute constant work rate protocol at 60 percent of VO2peak (VO2@60%), on a cycle ergometer. The average VO2peak was 33.48±8.22 ml×kg-1×min-1 (Range: 18.7 to 46.1 ml×kg-1×min-1). Following the six-minute constant work rate protocol, recovery half-time (T1/2VO2) and Tau were 17.01±3.51 seconds and 54.45±11.28 seconds, respectively. Arterial resting inflow was 2.77±1.51 ml×100ml-1×min-1, reactive hyperemic blood flow was 17.72±3.65 ml×100ml-1×min-1, venous capacitance was 2.86±0.72 percent, and venous outflow was 34.19±10.03 ml×100ml-1×min-1. Bivariate correlations revealed significant inverse associations between T1/2VO2 and the reactive hyperemic response (r=-0.48, p=0.03) and T1/2VO2 and venous outflow post-occlusion (r=-0.50, p=0.02). In conclusion, these findings suggest an important role of both the arterial and venous circulation on EPOC