TY - JOUR
T1 - Augmentation of the exercise pressor reflex in prehypertension
T2 - Roles of the muscle metaboreflex and mechanoreflex
AU - Choi, Hyun Min
AU - Stebbins, Charles L
AU - Lee, Og Taeg
AU - Nho, Hosung
AU - Lee, Joon Hee
AU - Chun, Jong Mok
AU - Kim, Kyung Ae
AU - Kim, Jong Kyung
PY - 2013/2
Y1 - 2013/2
N2 - This study investigated the hemodynamic mechanisms underlying the exaggerated blood pressure response to muscle contraction in prehypertensive humans and the potential role of skeletal muscle metabo- and mechanoreceptors in this response. To accomplish this, changes in peak mean arterial blood pressure (δMAP), cardiac output, and total peripheral resistance (δTPR) were compared between prehypertensive (n = 23) and normotensive (n = 19) male subjects during 2 min of static contraction (at 50% of maximal tension), 2 min of postexercise muscle ischemia (metaboreflex), and 1 min of passive dorsiflexion of the foot (tendon stretch, mechanoreceptor reflex). These variables were assessed before and during the interventions. Percentage increases from baseline in MAP and TPR in response to the exercise pressor reflex were augmented in the prehypertensives, compared with the normotensives (44% ± 5% vs. 33% ± 4% and 34% ± 15% vs. 2% ± 8%, respectively) (p < 0.05). Metaboreflex-induced increases in MAP and TPR were also augmented in the prehypertensives (28% ± 5% vs. 14% ± 4% and 36% ± 12% vs. 14% ± 9%, respectively) (p < 0.05). In response to the mechanoreflex, no differences in the percentage increase in MAP or TPR were seen between groups. The results indicate that the reflex pressor response to static contraction is augmented in prehypertension and suggest that this phenomenon is due, at least in part, to enhanced activation of metaboreceptors.
AB - This study investigated the hemodynamic mechanisms underlying the exaggerated blood pressure response to muscle contraction in prehypertensive humans and the potential role of skeletal muscle metabo- and mechanoreceptors in this response. To accomplish this, changes in peak mean arterial blood pressure (δMAP), cardiac output, and total peripheral resistance (δTPR) were compared between prehypertensive (n = 23) and normotensive (n = 19) male subjects during 2 min of static contraction (at 50% of maximal tension), 2 min of postexercise muscle ischemia (metaboreflex), and 1 min of passive dorsiflexion of the foot (tendon stretch, mechanoreceptor reflex). These variables were assessed before and during the interventions. Percentage increases from baseline in MAP and TPR in response to the exercise pressor reflex were augmented in the prehypertensives, compared with the normotensives (44% ± 5% vs. 33% ± 4% and 34% ± 15% vs. 2% ± 8%, respectively) (p < 0.05). Metaboreflex-induced increases in MAP and TPR were also augmented in the prehypertensives (28% ± 5% vs. 14% ± 4% and 36% ± 12% vs. 14% ± 9%, respectively) (p < 0.05). In response to the mechanoreflex, no differences in the percentage increase in MAP or TPR were seen between groups. The results indicate that the reflex pressor response to static contraction is augmented in prehypertension and suggest that this phenomenon is due, at least in part, to enhanced activation of metaboreceptors.
KW - Exercise pressor reflex
KW - Postexercise muscle ischemia
KW - Total vascular conductance
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U2 - 10.1139/apnm-2012-0143
DO - 10.1139/apnm-2012-0143
M3 - Article
C2 - 23438234
AN - SCOPUS:84874437655
VL - 38
SP - 209
EP - 215
JO - Applied Physiology, Nutrition and Metabolism
JF - Applied Physiology, Nutrition and Metabolism
SN - 1715-5312
IS - 2
ER -