TY - JOUR
T1 - A respiratory response to the activation of the muscle metaboreflex during concurrent hypercapnia in man
AU - Lykidis, C
AU - Kumar, Prem
AU - Vianna, L
AU - White, Michael
AU - Balanos, George
PY - 2009/1/1
Y1 - 2009/1/1
N2 - In this study, we aimed to assess the ventilatory and cardiovascular responses to the combined activation of the muscle metaboreflex and the ventilatory chemoreflex, achieved by postexercise circulatory occlusion (PECO) and euoxic hypercapnia (end-tidal partial pressure of CO2 7 mmHg above normal), respectively. Eleven healthy subjects (4 women and 7 men; 29 +/- 4.4 years old; mean +/- s.d.) undertook the following four trials, in random order: 2 min of isometric handgrip exercise followed by 2 min of PECO with hypercapnia; 2 min of isometric handgrip exercise followed by 2 min of PECO while breathing room air; 4 min of rest with hypercapnia; and 4 min of rest while breathing room air. Ventilation was significantly increased during exercise in both the hypercapnic (+3.17 +/- 0.82 l min-1) and the room air breathing trials (+2.90 +/- 0.26 l min-1; all P <0.05). During PECO, ventilation returned to pre-exercise levels when breathing room air (+0.52 +/- 0.37 l min-1; P > 0.05), but it remained elevated during hypercapnia (+3.77 +/- 0.23 l min-1; P <0.05). The results indicate that the muscle metaboreflex stimulates ventilation with concurrent chemoreflex activation. These findings have implications for disease states where effort intolerance and breathlessness are linked.
AB - In this study, we aimed to assess the ventilatory and cardiovascular responses to the combined activation of the muscle metaboreflex and the ventilatory chemoreflex, achieved by postexercise circulatory occlusion (PECO) and euoxic hypercapnia (end-tidal partial pressure of CO2 7 mmHg above normal), respectively. Eleven healthy subjects (4 women and 7 men; 29 +/- 4.4 years old; mean +/- s.d.) undertook the following four trials, in random order: 2 min of isometric handgrip exercise followed by 2 min of PECO with hypercapnia; 2 min of isometric handgrip exercise followed by 2 min of PECO while breathing room air; 4 min of rest with hypercapnia; and 4 min of rest while breathing room air. Ventilation was significantly increased during exercise in both the hypercapnic (+3.17 +/- 0.82 l min-1) and the room air breathing trials (+2.90 +/- 0.26 l min-1; all P <0.05). During PECO, ventilation returned to pre-exercise levels when breathing room air (+0.52 +/- 0.37 l min-1; P > 0.05), but it remained elevated during hypercapnia (+3.77 +/- 0.23 l min-1; P <0.05). The results indicate that the muscle metaboreflex stimulates ventilation with concurrent chemoreflex activation. These findings have implications for disease states where effort intolerance and breathlessness are linked.
U2 - 10.1113/expphysiol.2009.049999
DO - 10.1113/expphysiol.2009.049999
M3 - Article
C2 - 19801386
SN - 1469-445X
VL - 95
SP - 194
EP - 201
JO - Experimental Physiology
JF - Experimental Physiology
IS - 1
ER -