Acute Nutritional Ketosis During Early Recovery from Exercise Does Not Affect Skeletal Muscle Transcriptomic Response

Purpose: Recent research suggests that Ketone monoester (KME) supplementation may enhance skeletal muscle adaptation to exercise, possibly modulated be an increased secretion of erythropoietin (EPO) and increased muscle glycogen resynthesis, but the precise molecular pathways driving the response remain uncertain. Therefore, we aimed at characterising the modulation of skeletal muscle by KME through a genome-wide characterisation of the transcriptome early post-exercise. Methods: Following a randomized, double-blind, crossover design, recreationally active men [n= 9; age: 26 ± 5 (means ± SD); height: 1.80 ± 0.07 m; body mass: 80 ± 9 kg; V̇O2max: 47 ± 4 mL·kg-1·min-1]) completed two experimental trials where they ingested either 1.25 g/kg of KME (>96% (R)-3-hydroxybutyl (R)-3-hydroxybutyrate) or a taste-matched placebo (PLA) drink around exercise (90-min cycling at 60% of VO2max) in standardised conditions. . Venous blood samples were taken throughout baseline, exercise and recovery, and skeletal muscle biopsies were taken at baseline and 3-h post exercise. Results: KME intake elevated serum ßHB concentrations post-exercise to 3.3 ± 0.5 mM and remained elevated levels during recovery (range: ~4.0–4.7 mM). Remarkably, there was no marked upregulation or downregulation of differentially expressed genes at 3-h post-exercise with KME supplementation compared to PLA. Although, baseline serum EPO levels were higher in PLA (12.8 ± 3.9 IU/L) compared to KME (10.1 ± 5.7 IU/L) and remained slightly higher in PLA throughout recovery, there was not significant difference between conditions. Pre- and post- exercise muscle glycogen concentrate were similar between conditions (KME PRE: 501 ± 118 mmol/kg, KME POST, 284 ± 117 mmol/kg, PLA PRE: 492 ± 102 mmol/kg, PLA POST: 282 ± 184 mmol/kg). Conclusions: Our findings indicate that despite a sustained post-exercise increase in serum ßHB concentrations, KME supplementation did not induce transcriptional changes in skeletal muscle. Additionally, in contrast to previous studies, KME did not affect glycogen concentrations or serum EPO levels during the first 3-hours post-exercise.