Acute Ketone Supplementation and Exercise Performance: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of randomized controlled trials
PubMed 32045881 · doi:10.1123/ijspp.2019-0918
What was done
A systematic review and meta-analysis of randomized controlled trials searched PubMed, Web of Science, and SPORTDiscus through July 21, 2019. The authors evaluated the acute effects of ketone supplementation (esters or salts) compared to a non-ketone control drink on exercise performance (primary outcome) and physiological and perceptual responses (secondary outcomes). Standardized mean differences (Hedges g) and 95% confidence intervals were pooled using a random-effects model.
What was found
Thirteen studies met inclusion criteria. No significant difference was observed for overall exercise performance between ketone supplementation and control (Hedges g = -0.05; 95% CI, -0.30 to 0.20; P = .68). Subgroup analyses showed no significant differences for endurance time-trial performance (g = -0.04; 95% CI, -0.35 to 0.28; P = .82), ketone esters alone (g = -0.07; 95% CI, -0.38 to 0.24; P = .66), or ketone salts alone (g = -0.02; 95% CI, -0.45 to 0.41; P = .93). Despite elevated plasma ketone levels across all studies, no consistent effects were observed for plasma lactate, glucose, respiratory exchange ratio, oxygen uptake, ventilatory rate, heart rate, or rating of perceived exertion.
Why it matters
This meta-analysis demonstrates that acute exogenous ketone ingestion does not provide ergogenic benefits for short- to moderate-duration exercise up to roughly 50 minutes, challenging commercial claims of acute performance enhancement.
Limits
The abstract does not report the total participant sample size, demographics, or training status across the 13 trials. Findings are limited to acute supplementation and exercise lasting up to approximately 50 minutes, leaving potential effects on chronic usage or ultra-endurance exercise unaddressed.
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