Author(s): LAURIKS, W., ROBBERECHTS, R., STALMANS, M., KUSTERS, M., RAMAEKERS, M., KOPPO, K., POFFÉ, C., Institution: KU LEUVEN: KATHOLIEKE UNIVERSITEIT LEUVEN, Country: BELGIUM, Abstract-ID: 2020

INTRODUCTION:
Altitude training programs, particularly live high-train low (LHTL) protocols, are widely used by endurance athletes with the aim of enhancing performance through adaptations such as increases in hemoglobin mass and muscle capillary density. Recently, post-exercise ketone ester (KE) ingestion has been shown to increase serum [EPO] compared with a placebo (1). Furthermore, KE has also been shown to enhance skeletal muscle capillarization and elevate serum [EPO] in response to three weeks of excessive exercise training (2). These findings suggest that KE may induce similar effects as altitude exposure, and as such may potentially elevate the physiological and performance adaptations induced by LHTL.
METHODS:
Eighteen recreational cyclists (9 male, 9 female; VO2max: 52 +/- 8 mL/kg/min) performed a five-week LHTL camp involving progressive normobaric hypoxic exposure (2000-3000m simulated altitude) and 4-7 training sessions per week, followed by a one-week tapering period under normoxic conditions. Throughout this six-week period, subjects received either 25g KE (n=9) or an isocaloric placebo (CON; n=9) after each training session and 30 min pre-sleep. Experimental measurements were performed before (PRE), after (POST) LHTL, and after the taper (POST+7). Measurements included a 30-minute time trial (TT30), determination of VO2max, and hemoglobin mass. Furthermore, venous blood samples and muscle biopsies were obtained for determination of serum [EPO] and to assess skeletal muscle capillarization, as well as VEGF and HIF-1a protein content.
RESULTS:
In both groups, mean power output during TT30 improved by 9% alongside increases in VO2max (+8%) and absolute hemoglobin mass (+9%) from PRE to POST+7. EPO concentrations rose from ~4.2 mIU/mL at baseline to ~6.0 mIU/mL after 14 hours and remained above 5 mIU/mL during the entire intervention with significant increase at week 2 and POST. Ingestion of KE did not further improve any of these responses. Skeletal muscle capillarization, as well as vascular endothelial growth factor (VEGF) and hypoxia-inducible factor 1 alpha (HIF-1a), were neither impacted by LHTL nor by KE.
CONCLUSION:
These data indicate that post-exercise and pre-sleep KE ingestion does not provide beneficial effects on performance or physiological adaptations during a LHTL training program in recreational cyclists.