Beta-Blocker Type Effect on Substrate Oxidation during HIIE in Heart Failure Patients: Pilot Data

Area of Science:

• Cardiology
• Exercise Physiology
• Pharmacology

Background:

• Limited data exists on how different beta-blocker generations affect substrate oxidation during high-intensity exercise.
• Chronic heart failure with reduced ejection fraction (HFrEF) impacts exercise capacity and substrate metabolism.

Purpose of the Study:

• To investigate the differential effects of vasodilating versus non-vasodilating beta-blockers on substrate oxidation during high-intensity intermittent exercise (HIIE) in HFrEF patients.
• To compare substrate utilization patterns between beta-blocker regimens in this population.

Main Methods:

• Eighteen male HFrEF patients were randomized into a crossover design with four HIIE protocols.
• Participants received either β1-specific beta-blockers with an alpha-1 blocker (vasodilating) or β1-non-specific beta-blockers (non-vasodilating).
• Carbohydrate and lipid oxidation were quantified at rest and during exercise, with energy expenditure and exercise duration recorded.

Main Results:

• Beta-blocker type significantly impacted carbohydrate and lipid oxidation percentages at rest and during exercise.
• Absolute carbohydrate oxidation (g/min) differed at 10 minutes of exercise (p=0.029).
• Higher carbohydrate oxidation was observed with vasodilating beta-blockers compared to non-vasodilating ones.

Conclusions:

• Beta-blocker type affects substrate oxidation during HIIE in HFrEF patients.
• No significant influence of beta-blocker type was found on overall energy expenditure or total exercise time.
• These findings suggest a potential role for beta-blocker selection in modulating exercise metabolism in HFrEF.