Premium
Isolated Knee Extensor Exercise Training Improves Skeletal Muscle Vasodilation, Blood Flow and Functional Capacity in HFpEF Patients
Author(s) -
Hearon Christopher,
Samels Mitchel,
Dias Katrin,
Levine Benjamin,
Sarma Satyam
Publication year - 2021
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2021.35.s1.04403
Subject(s) - medicine , cardiology , blood pressure , cardiac output , vo2 max , vasodilation , blood flow , aerobic exercise , vascular resistance , hemodynamics , brachial artery , heart rate
Background Patients with HFpEFexperience severe exercise intolerance due in part to impaired skeletal muscle vascular function during exercise. Whole body exercise interventions yield only modest improvements in cardiac function and functional capacity, and are often not well‐tolerated due to severe dyspnea. Therefore, training interventions that isolate smaller muscle groups to improve vascular function may be effective at improving exercise capacity in HFpEF patients while minimizing shortness of breath. Hypothesis Eight weeks of isolated knee extension (KE) exercise training will improve leg blood flow and increase exercise capacity in patients with HFpEF. Methods Nine HFpEF patients (66±5 years, 6 females) performed graded KE exercise (5, 10, and 15W) and maximal aerobic exercise testing (cycle ergometer) before and after 8 weeks of isolated KE training (3x per week, 30 min per leg). Vascular function was assessed by measuring skeletal muscle blood flow (femoral artery ultrasound), mean arterial pressure (ECG‐gated sphygmomanometer), and femoral vascular conductance (FVC; index of vasodilation) during graded KE exercise. Functional capacity, quantified as peak pulmonary oxygen uptake (V̇O 2 , Douglas bags), peak cardiac output (Q c , acetylene rebreathing) and arterial‐venous oxygen difference (a‐v O 2 diff ) were measured during a graded maximal cycle exercise to assess cardiac and peripheral adaptations to isolated KE training. Results Eight weeks of isolated KE training lowered blood pressure (Δ: pre: 22±13, post: 12±10.1 mmHg; P=0.02) and improved blood flow (Δ: pre: 950±332, post: 1263±355 ml/min; P=0.02) during 15W isolated KE exercise. The increase in blood flow was due to improved skeletal muscle vasodilation (ΔFVC: pre: 810±417, post: 1234±347 ml/min/100mmHg; P=0.01). During maximal exercise testing, KE training had a small but variable effect on peak Q c (pre: 12.5±3.7, post: 13.2±3.9 l/min; P=0.19), and peripheral oxygen extraction (a‐v O 2 diff : pre: 10.6±1.8, post: 11.0±1.7 ml/100ml; P=0.17), but resulted in a 13% improvement in peak V̇O 2 (pre:12.5±5.5, post: 14.0±6.0; P=0.01). Conclusions Eight weeks of isolated KE training improved skeletal muscle vascular function and blood flow delivery during KE exercise, resulting in improved functional capacity in patients with HFpEF. Exercise interventions aimed at increasing skeletal muscle and vascular function may be effective therapeutic options for HFpEF patients that experience severe dyspnea during whole body exercise.