A major symptom of heart disease is exercise intolerance, which is thought to be caused by overactivation of the sympathetic nervous system (SNS) via limb edema stimulating group III/IV afferent feedback mechanisms (Figure 1) (7, 8 & 9). Accurately replicating the afferent feedback during exercise is difficult in both healthy and diseased subjects, due to an inability to directly measure afferents in human subjects. Thus most information about the response of afferents comes from post-exercise limb occlusion studies (2). There has been some indication that using a lower sub-systolic pressure cuff during exercise can more accurately represent the ventilatory response (4 & 6).
A recent study by Keller-Ross et al. (5) investigated the ventilatory response using lower extremity sub-systolic venous occlusion during exercise (Figure 1). The authors had participants cycle at 30% VO2 max with bilateral pressure tourniquets attached to their …show more content…
(5) provided some of the first results that sub-systolic occlusion results in afferent feedback activation. While further experiments are needed to determine the possible role of gender and muscle metabolics on the ventilatory response, this study provides significant insight into the impact of moderate limb occlusion on the muscle afferent group III/IV response. These results are especially significant in heart failure patients suffering from limb edema and exercise intolerance which are common symptoms of the condition (3). If the limb edema is causing the activation of afferent group III/IV pathways, then inhibiting these is a possible treatment option (9). Exploring the link between heart failure and muscle afferents may provide further areas of treatment and symptom management. While some studies have already investigated inhibition of afferent feedback as a way to reduce the ventilatory response in heart failure patients (8) more research is needed before these treatments become
A recent study by Keller-Ross et al. (5) investigated the ventilatory response using lower extremity sub-systolic venous occlusion during exercise (Figure 1). The authors had participants cycle at 30% VO2 max with bilateral pressure tourniquets attached to their …show more content…
(5) provided some of the first results that sub-systolic occlusion results in afferent feedback activation. While further experiments are needed to determine the possible role of gender and muscle metabolics on the ventilatory response, this study provides significant insight into the impact of moderate limb occlusion on the muscle afferent group III/IV response. These results are especially significant in heart failure patients suffering from limb edema and exercise intolerance which are common symptoms of the condition (3). If the limb edema is causing the activation of afferent group III/IV pathways, then inhibiting these is a possible treatment option (9). Exploring the link between heart failure and muscle afferents may provide further areas of treatment and symptom management. While some studies have already investigated inhibition of afferent feedback as a way to reduce the ventilatory response in heart failure patients (8) more research is needed before these treatments become