This study investigates how orally ingested exogenous ketone monoester supplements affect circulating hormone concentrations in healthy young adult males after a single session of resistance exercise. Resistance exercise is known to stimulate an acute increase in the circulating concentration of various hormones that are involved in the regulation of muscle mass, including testosterone, growth hormone (GH), and insulin-like growth factor-1 (IGF-1). Recently, there has been growing interest in how nutritional supplements impact these natural hormone responses at rest. One such intervention is the oral ingestion of exogenous ketone body supplements. Ketone bodies (i.e., β-hydroxybutyrate (β-HB), acetoacetate (AcAc), and acetone) are naturally occurring compounds that are normally produced by the body during prolonged fasting/starvation, or in response to a "ketogenic" diet (a diet very high in fat and very low in carbohydrates). These ketone body supplements taken in the form of a ketone monoester can quickly raise blood ketone levels without needing to change your diet. Recent research has shown that the ingestion of exogenous ketone supplements or following a 'ketogenic diet' can alter the concentration of certain hormones measured in blood samples at rest. However, the effects of ketone monoester intake on the exercise-induced elevation in circulating hormones is yet to be explored. Therefore, the purpose of this study is to examine how elevated β-HB, induced via the ingestion of the ketone monoester (R)-3-hydroxybutyl-(R)-3-hydroxybutyrate, affects blood concentrations of various anabolic hormones, during post-exercise recovery in healthy young adult males, compared to a placebo drink (flavoured water).
A within-subject crossover design will be used for this randomized, double-blind, placebo-controlled study in healthy males to investigate the impact of ketone monoester (KET) intake on circulating (blood) concentrations of 'anabolic' and other hormones. There are two treatment arms in this crossover trial, including one KET arm and one placebo group. A total of 12 participants will be enrolled and undergo both treatment phases with a minimum 7-day washout period between lab visits. The study will include a screening visit (Visit 1), 10-repetition maximum (10-RM) testing (visit 2), where participants' 10-RM will be determined for each exercise machine used, experimental trial (visit 3), minimum 7-day washout, followed by the phase 2 of the experimental trial (visit 4). During the experimental trials, participants will arrive to the laboratory in an overnight fasted state, and the KET or placebo drink will then be administered following basal blood collection. Then, participants will perform a lower-body resistance exercise session consisting of 5 sets of 10 repetitions of leg press and 3 sets of 12 repetitions of leg extension/leg curl supersets at 95% of their determined 10-RM. Following exercise, another dose of the nutritional treatment will be administered. Arterialized blood samples will then be collected at 13 postprandial timepoints during the 1-hour rested period and the 4-hour post-exercise recovery period to measure changes in plasma glucose and insulin concentration. Arterialized blood samples will also be utilized for quantitation of anabolic hormones, including testosterone, IGF-1, GH, cortisol, luteinizing hormone, sex-hormone binding globulin, dehydroepiandrosterone, estrogen, progesterone, and follicle-stimulating hormone. Additionally, changes in capillary blood β-HB concentration will be assessed throughout the trials by collecting capillary blood samples at baseline and 11 postprandial timepoints during the 1-hour rested period and the 4-hour post-exercise recovery period.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
TRIPLE
Enrollment
12
Ketone monoester supplement (R)-3-hydroxybutyl (R)-3-hydroxybutyrate based on participants' body weight (0.36g/kg body weight). The ketone brand name: delta G Oxford Ketone Ester.
\- Flavoured water (non-caloric bitter + citrus flavours)
\- 5 sets of 10 repetitions of leg press and 3 sets of 12 repetitions of leg extension/leg curl 'supersets' (1 set of each back to back with no rest in between sets) at 95% of their 10-RM. Between-set rest intervals for the leg exercises will be 60 seconds.
McGill University
Montreal, Quebec, Canada
Area under the curve for testosterone concentration.
Serum concentration of testosterone (nmol/l) and corresponding area under the curve (AUC), measured at baseline and over 4 hours into the post-exercise recovery period.
Time frame: Baseline and over 4 hours into the post-exercise recovery period
Time-course data for testosterone concentration.
Serum concentration of testosterone (nmol/l) measured at baseline and at 13 timepoints (t = -60, -45, -30, 0, 15, 30, 45, 60, 90, 120, 150, 180, 240 min).
Time frame: Baseline, 1 hour pre-exercise and 4-hours during the post-exercise recovery period.
Area under the curve for growth hormone concentration
Serum concentration of growth hormone (μmol/L) and corresponding area under the curve (AUC), measured at baseline and over the post-exercise recovery period.
Time frame: Baseline and over 4 hours into the post-exercise recovery period
Time-course data for growth hormone concentration.
Changes in serum concentration of growth hormone (μmol/L) measured at 13 timepoints (t = -60, -45, -30, 0, 15, 30, 45, 60, 90, 120, 150, 180, 240 min).
Time frame: Baseline, 1 hour pre-exercise and 4-hours during the post-exercise recovery period.
Area under the curve for insulin-like growth factor-1 (IGF-1) concentration
Serum concentration of IGF-1 (nmol/L) and corresponding area under the curve (AUC), measured at baseline and over the post-exercise recovery period.
Time frame: Baseline and 4 hours into the post-exercise recovery period
Time-course data for IGF-1 concentration
Changes in serum concentration of IGF-1 (nmol/L) measured at baseline and at 13 timepoints (t = -60, -45, -30, 0, 15, 30, 45, 60, 90, 120, 150, 180, 240 min).
Time frame: Baseline, 1 hour pre-exercise and 4-hours during the post-exercise recovery period.
Area under the curve for cortisol concentration.
Serum concentration of cortisol (nmol/L) and its corresponding area under the curve (AUC), measured at baseline and over the post-exercise recovery period.
Time frame: Baseline and over 4 hours into the post-exercise recovery period.
Time-course data for cortisol concentration.
Changes in serum concentration of cortisol (nmol/L) measured at baseline and at 13 timepoints (t = -60, -45, -30, 0, 15, 30, 45, 60, 90, 120, 150, 180, 240 min).
Time frame: Baseline, 1 hour pre-exercise and 4-hours during the post-exercise recovery period.
Area under the curve for luteinizing hormone concentration
Serum concentration of luteinizing hormone concentrations (IU/L) and corresponding area under the curve (AUC), measured at baseline and over the post-exercise recovery period.
Time frame: Baseline and 4 hours into the post-exercise recovery period
Time-course data for luteinizing hormone concentration
Changes in serum concentration of luteinizing hormone concentrations (IU/L) measured at13 timepoints (t = -60, -45, -30, 0, 15, 30, 45, 60, 90, 120, 150, 180, 240 min).
Time frame: Baseline, 1 hour pre-exercise and 4-hours during the post-exercise recovery period.
Area under the curve for dehydroepiandrosterone (DHEA) concentration
Serum concentration of DHEA (μmol/L) and corresponding area under the curve (AUC), measured at baseline and over the post-exercise recovery period.
Time frame: Baseline and 4 hours into the post-exercise recovery period.
Time-course data for DHEA concentration
Changes in serum concentration of DHEA (μmol/L) measured at baseline and at 13 timepoints (t = -60, -45, -30, 0, 15, 30, 45, 60, 90, 120, 150, 180, 240 min).
Time frame: Baseline, 1 hour pre-exercise and 4-hours during the post-exercise recovery period.
Area under the curve for sex hormone-binding globulin (SHBG) concentration
Serum concentration of SHBG (nmol/L) and corresponding area under the curve (AUC), measured at baseline and during the post-exercise recovery period.
Time frame: Baseline and over 4 hours into the post-exercise recovery period.
Time-course data for SHBG concentration.
Changes in serum concentration of SHBG (nmol/L) measured at baseline and at 13 timepoints (t = -60, -45, -30, 0, 15, 30, 45, 60, 90, 120, 150, 180, 240 min).
Time frame: Baseline, 1 hour pre-exercise and 4-hours during the post-exercise recovery period.
Area under the curve for progesterone concentration
Serum concentration of progesterone (nmol/L) and its corresponding area under the curve (AUC), measured at baseline and during the post-exercise recovery period.
Time frame: Baseline and over 4 hours into the post-exercise recovery period.
Time-course data for progesterone concentration.
Changes in serum concentration of progesterone (nmol/L) measured at 13 timepoints (t = -60, -45, -30, 0, 15, 30, 45, 60, 90, 120, 150, 180, 240 min).
Time frame: Baseline, 1 hour pre-exercise and 4-hours during the post-exercise recovery period.
Area under the curve for estrogen concentration
Serum estrogen concentration (pmol/mL) and corresponding area under the curve (AUC), measured at baseline and during the post-exercise recovery period.
Time frame: Baseline and over 4 hours into the post-exercise recovery period.
Time-course data for estrogen concentration
Changes in serum concentration for estrogen (pmol/mL) measured at 13 timepoints (t = -60, -45, -30, 0, 15, 30, 45, 60, 90, 120, 150, 180, 240 min).
Time frame: Baseline, 1 hour pre-exercise and 4-hours during the post-exercise recovery period.
Area under the curve for follicle stimulating hormone (FSH) concentration
Serum concentration of FSH (IU/l) and corresponding area under the curve (AUC), measured at baseline and during the post-exercise recovery period.
Time frame: Baseline and over 4 hours into the post-exercise recovery period.
Time-course data for FSH concentration.
Changes in serum concentration for FSH (IU/l) measured at baseline and at 13 timepoints (t = -60, -45, -30, 0, 15, 30, 45, 60, 90, 120, 150, 180, 240 min).
Time frame: Baseline, 1 hour pre-exercise and 4-hours during the post-exercise recovery period.
Area under the curve for glucose concentration
Plasma glucose concentration (mmol/L) and its corresponding area under the curve (AUC), measured at baseline and over the post-exercise recovery period.
Time frame: Baseline and 4 hours into the post-exercise recovery period
Time-course data for glucose concentration
Changes in plasma glucose concentration (mmol/L) measured at 13 timepoints (t = -60, -45, -30, 0, 15, 30, 45, 60, 90, 120, 150, 180, 240 min).
Time frame: Baseline, 1 hour pre-exercise and 4-hours during the post-exercise recovery period.
Area under the curve for insulin concentration
Plasma concentration of insulin (pmol/L) and corresponding area under the curve (AUC), measured at baseline and over the post-exercise recovery period.
Time frame: Baseline and 4 hours into the post-exercise recovery period
Time-course data for insulin concentration
Changes in plasma concentration of insulin (pmol/L) measured at baseline and at 13 timepoints (t = -60, -45, -30, 0, 15, 30, 45, 60, 90, 120, 150, 180, 240 min).
Time frame: Baseline, 1 hour pre-exercise and 4-hours during the post-exercise recovery period.
Area under the curve for β-HB concentrations
Capillary blood β-OHB concentration (mmol/L) and corresponding area under the curve (AUC), measured at baseline and over the post-exercise recovery period.
Time frame: Baseline and 4 hours into the post-exercise and postprandial period
Time-course data for β-HB concentrations
Changes in capillary blood β-HB concentrations (mmol/L) measured at 12 timepoints (t = -60, -45, -30, 0, 15, 30, 60, 90, 120, 150, 180, 240 min).
Time frame: Baseline, 1 hour pre-exercise and 4-hours during the post-exercise recovery period.
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