Arterial Baroreflex-Skeletal Muscle Metaboreflex Interaction During Graded Metaboreflex Activation in Hypertensive Adults

Authors

Isabella Arana Rios, The University of Texas Southwestern Medical Center, Dallas, TX, USA; Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, TX, USAFollow
Giorgio Manferdelli, Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, TX, USA; The University of Texas Southwestern Medical Center, Dallas, TX, USAFollow
Denis J. Wakeham, Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, TX, USA; The University of Texas Southwestern Medical Center, Dallas, TX, USAFollow
Scott L. Davis, Department of Applied Physiology and Sport Management, Southern Methodist University, Dallas, TX, USA; The University of Texas Southwestern Medical Center, Dallas, TX, USAFollow
Paul J. Fadel, Department of Kinesiology, The University of Texas at Arlington, Arlington, TX, USAFollow
Sarah L. Hissen, Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, TX, USA; The University of Texas Southwestern Medical Center, Dallas, TX, USAFollow
Christopher M. Hearon Jr., Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, TX, USA; The University of Texas Southwestern Medical Center, Dallas, TX, USAFollow

Abstract

The skeletal muscle metaboreflex is a blood pressure-raising reflex originating from skeletal muscle that contributes to resetting the operating point of the arterial baroreflex during exercise. In healthy adults, sympathetic baroreflex sensitivity (BRS) increases during metaboreflex activation, whereas cardio-vagal BRS is unchanged. Adults with hypertension (HTN) have exaggerated pressor responses to metaboreflex activation; however, to our knowledge, no studies have examined sympathetic or cardio-vagal BRS during metaboreflex activation in adults with HTN. HYPOTHESIS: We hypothesized that sympathetic and cardio-vagal BRS would be reduced during graded muscle metaboreflex activation in adults with HTN. METHODS: Thirty-five adults with HTN (18 females; age: 43±9 yrs) were studied. Blood pressure (finger photoplethysmography), heart rate (HR; ECG) and muscle sympathetic nerve activity (MSNA; peroneal nerve microneurography; n=28) were measured at baseline (BL), and during three consecutive bouts of ischemic isometric handgrip exercise (60s, 20% of maximum), each followed by 2-min-45s of ischemic rest to isolate the metaboreflex (MET1, MET2, and MET3). BRS was quantified as cardio-vagal BRS (cBRS, sequence method; n=28) and sympathetic BRS (sBRS, weighted linear regression of diastolic blood pressure and MSNA burst incidence [BI]; 3-mmHg bins, accepted if r>0.7; n=24) during the last 2 min of BL and each MET period. Data were analyzed by a mixed-effects model. RESULTS: Adults with HTN showed graded increases in MAP during metaboreflex activation (BL: 106±12; MET1: 115±16; MET2: 123±18; MET3: 132±21 mmHg; all p<0.001). HR was increased from BL similarly across MET1 to MET3 (BL: 64±9 vs. MET1: 71±11 bpm MET2: 73±12 mmHg, MET3: 73±12 mmHg, all p<0.001). Compared to BL, MSNA BI was increased by MET2 and MET3 (BL: 38±17; MET1: 36±19; MET2: 44±19, MET3:59±18 bursts/100heartbeats; interaction: p<0.001). There was no changes in cBRS (BL: 17±17; MET1: 17±10; MET2: 18±12; MET3: 14±7 ms/mmHg; interaction: p=0.171) or sBRS (BL: -3.5±1.6; MET1: -4.3±1.1; MET2: -4.0±1.4; MET3: -4.0±2.0 bursts/100heartbeats/mmHg; interaction: p=0.474) during graded metaboreflex activation. CONCLUSION: Graded activation of the metaboreflex in adults with HTN had no effect on cBRS or sBRS. These data indicate that sympathetic BRS is not increased by metaboreflex activation in adults with HTN, as reported previously in healthy adults.

Recommended Citation

Arana Rios, Isabella; Manferdelli, Giorgio; Wakeham, Denis J.; Davis, Scott L.; Fadel, Paul J.; Hissen, Sarah L.; and Hearon, Christopher M. Jr. (2026) "Arterial Baroreflex-Skeletal Muscle Metaboreflex Interaction During Graded Metaboreflex Activation in Hypertensive Adults," International Journal of Exercise Science: Conference Proceedings: Vol. 2: Iss. 18, Article 127.
Available at: https://digitalcommons.wku.edu/ijesab/vol2/iss18/127