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Background: The etiology of exercise intolerance in heart failure with preserved ejection fraction (HFpEF) is multifactorial. Several contributing pathways may be improved by ketone ester (KE).
Objectives: This study aims to determine whether KE improves exercise tolerance in HFpEF.
Methods: KETO-HFpEF (Ketogenic Exogenous Therapies in HFpEF) is a randomized, crossover, placebo-controlled trial of acute KE dosing in 20 symptomatic HFpEF participants. Coprimary endpoints include peak oxygen consumption (VO) during incremental cardiopulmonary exercise testing and time to exhaustion during an additional constant-intensity exercise (75% peak workload) bout.
Results: The average age was 71 ± 8 years, 60% were women, and 65% were White. KE did not improve peak VO (KE: 10.4 ± 3.6 vs placebo: 10.5 ± 4.0 mL/kg/min; P = 0.75). At rest, heart rate, biventricular systolic function, and cardiac output (0.6 L/min [95% CI: 0.3-1.0 L/min]) were greater with KE vs placebo, whereas total peripheral resistance (-3.2 WU [95% CI: -5.2 to -1.2 WU]) and the arteriovenous oxygen content difference (-0.7 mL of O/dL blood [95% CI: -1.2 to -0.2 mL]) were lower. These differences mostly disappeared during incremental exercise. KE did not improve exercise endurance during the constant-intensity protocol (9.7 ± 7.3 minutes vs 8.7 ± 4.4 minutes; P = 0.51). In 6 participants receiving 6,6-H-glucose infusions during constant-intensity exercise, plasma glucose appearance rate before and during exercise was lower with KE (-0.24 mg/kg/min; P < 0.001). During both exercise protocols, KE lowered: 1) respiratory exchange ratios, demonstrating decreased systemic carbohydrate use; 2) nonesterified fatty acids and glucose; and 3) estimated left ventricular filling pressures (E/e').
Conclusions: Despite robust ketosis, shifting substrate use away from carbohydrates, and decreasing estimated left ventricular filling pressures, acute KE supplementation did not improve peak VO or constant-intensity exercise in HFpEF. (Ketogenic Exogenous Therapies in HFpEF [KETO-HFpEF]; NCT04633460).
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http://dx.doi.org/10.1016/j.jchf.2025.03.002 | DOI Listing |
JACC Heart Fail
March 2025
Division of Cardiology, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA; Cardiovascular Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA. Electronic address:
Background: The etiology of exercise intolerance in heart failure with preserved ejection fraction (HFpEF) is multifactorial. Several contributing pathways may be improved by ketone ester (KE).
Objectives: This study aims to determine whether KE improves exercise tolerance in HFpEF.
Med Sci Sports Exerc
July 2025
College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, QATAR.
Introduction/purpose: The oxygen uptake (V̇O 2 )-power output (PO) relationship from incremental exercise needs to be adjusted to accurately prescribe constant-intensity exercise training. We assessed the accuracy of a "step-ramp-step" (SRS) protocol for prescribing constant PO exercise within moderate-intensity (below estimated lactate threshold, θ LT ), heavy-intensity (between θ LT and respiratory compensation point, RCP), and severe-intensity (above RCP) domains in 14 patients with coronary artery disease (CAD).
Methods: The SRS protocol included the following: 6 min of cycling at 25-40 W, a ramp-incremental test until task failure (5-15 W · min -1 ), and, after a 20 min recovery, 12 min of cycling at ~50%-60% of peak ramp PO.
J Equine Vet Sci
April 2025
Laboratory of Equine Exercise Physiology and Pharmacology (LAFEQ), Department of Animal Morphology and Physiology, School of Agricultural and Veterinarian Sciences (FCAV), São Paulo State University (UNESP), Jaboticabal 14884-900, São Paulo, Brazil. Electronic address:
In humans, there is an ongoing academic discussion about measuring plasma lactate concentration ([La]) during an incremental exercise test (IET) to establish thresholds that can predict the maximal lactate steady state (MLSS). Training studies on horses have utilized the onset of [La] (OBLA), also known as V, the velocity at which the [La] of 4 mM is reached. This study assesses the effectiveness of four methods for estimating the MLSS in teaching horses.
View Article and Find Full Text PDFPlacenta
March 2025
Graduate Program in Nutrition, Health Sciences Center, Federal University of Pernambuco, Recife, PE, Brazil; Graduate Program in Nutrition, Physical Activity and Phenotypic Plasticity, Academic Center of Vitoria, Federal University of Pernambuco, Vitória de Santo Antão, Brazil; Physical Education
Introduction: Resistance training during pregnancy provides benefits for the mother and fetus, but little is known about the effects of resistance training on placental structure and function or the repercussions of modifying resistance training intensity on the mother-fetus-placenta triad.
Methods: Female Wistar rats were submitted to resistance training involving a ladder climb (80 % of maximum load carried (MLC), 5-day/week for 3-weeks) before pregnancy. After confirmation of mating, the rats were randomly divided into three groups, according to resistance training intensity during pregnancy: constant-intensity training (CIT, trained at 80 % of MLC through gestation), decreasing-intensity training (DIT, 80 % of MLC during first and second weeks of gestation and 50 % of MLC in the third week), and undulating-intensity training (UIT, 50 % of MLC in the first and third weeks, and 80 % of MLC in the second week).
J Sports Sci Med
December 2024
EA4660, C3S Culture Sport Health Society, University of Franche-Comté, Besançon, France.
There is little evidence of the acute effect of random practice, performed by solely varying the intensity but not the task itself, as compared to block practice, i.e. when one task is repeated in a constant manner.
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