Cannabidiol (CBD) is widely available and marketed as having therapeutic properties. Over-the-counter CBD is unregulated, many of the therapeutic claims lack scientific support, and controversy exists as to the safety of CBD-liver interaction. The study aims were to compare the pharmacokinetics of commercial CBD and CBD metabolites following the ingestion of five different CBD formulations, determine the influence of CBD on food induced thermogenesis, determine the influence of food on CBD pharmacokinetics, and determine the influence of CBD on markers of liver function. Fourteen males (body mass index ≥ 25 kg/m²) were studied in a placebo-controlled, randomized, crossover design. On five occasions, different CBD formulations were ingested (one per visit). On two additional occasions, CBD or placebo was ingested following a meal. CBD servings were standardized to 30 mg. Considerable pharmacokinetic variability existed between formulations; this pharmacokinetic variability transferred to several of the metabolites. CBD did not influence food induced thermogenesis but did favorably modify early insulin and triglyceride responses. Food appreciably altered the pharmacokinetics of CBD. Finally, CBD did not evoke physiologically relevant changes in markers of liver function. Collectively, these data suggest that consumers should be aware of the appreciable pharmacokinetic differences between commercial CBD formulations, CBD is unlikely to influence the caloric cost of eating but may prove to be of some benefit to initial metabolic responses, consuming CBD with food alters the dynamics of CBD metabolism and increases systemic availability, and low-dose CBD probably does not represent a risk to normal liver function.

Data supporting the physiological effects of cannabidiol (CBD) ingestion in humans are conflicting. Differences between CBD preparations and bioavailability may contribute to these discrepancies. Further, an influence of body composition on CBD bioavailability is feasible, but currently undocumented. The aims of this study were to: (1) compare the pharmacokinetics of five oral CBD preparations over 4 h; (2) examine the relationship between body composition and CBD pharmacokinetics; and, (3) explore the influence of CBD on heart rate variability. In total, five preparations of CBD, standardized to 30 mg, were orally administered to 15 healthy men and women (21–62 years) in a randomized, crossover design. Prior to and 60 min following CBD ingestion, heart rate variability was determined. Body composition was assessed using dual energy X-ray absorptiometry. Peak circulating CBD concentration, time to peak concentration, and area under the curve was superior in a preparation comprising 5% CBD concentration liquid. Fat free mass was a significant predictor (R² = 0.365, p = 0.017) of time to peak concentration for this preparation. Several heart rate variability parameters, including peak frequency of the high frequency band, were favorably, but modestly modified following CBD ingestion. These data confirm an influence of CBD preparation and body composition on CBD bioavailability, and suggest that acute CBD ingestion may have a modest influence on autonomic regulation of heart rate.

The purpose of the study was to describe and compare the pharmacokinetics of five commercial edible marijuana products, determine the influence of body composition on pharmacokinetics, and, in light of epidemiology suggesting marijuana may offer diabetes protection, explore the influence of edible marijuana on glucose tolerance. Seven regular users of marijuana self-administered five edible products in a randomized crossover design; each product contained 10 mg of delta-9-tetrahydrocannabinol (THC). Thirty minutes following marijuana ingestion, participants imbibed a 75 g glucose beverage. Time-to-peak plasma THC concentration ranged between 35 and 90 min; maximal plasma THC concentration (C_max) ranged between 3.2 and 5.5 ng/mL. Differences between products in plasma THC concentration during the first 20–30 min were detected (p = 0.019). Relations were identified between body composition and pharmacokinetic parameters for some products; however, none of these body composition characteristics were consistently related to pharmacokinetics across all five of the products. Edible marijuana had no effect on oral glucose tolerance compared with a marijuana-free control (Matsuda Index; p > 0.395). Commercially available edible marijuana products evoke different plasma THC concentrations shortly after ingestion, but do not appear to influence acute glucose regulation. These data may allow recreational marijuana users to make informed decisions pertaining to rates of edible marijuana ingestion and avoid overdose.

Exercise training represents a crucial lifestyle intervention for improving blood pressure, yet many adults do not meet recommendations for physical activity. Heat therapy was tested against aerobic exercise training as a potential alternative lifestyle intervention. Neither heat therapy nor exercise training was effective for the treatment of hypertension.

Introduction: The release of interleukin (IL)-6 from contracting skeletal muscle is thought to contribute to some of the health benefits bestowed by exercise. This IL-6 response seems proportional to exercise volume and to lactate production. Unfortunately, high volumes of exercise are not feasible for all people. Caffeine augments the magnitude of increase in circulating IL-6 in response to high-intensity and long-duration exercise. Caffeine also increases circulating concentrations of lactate during exercise. We hypothesized that caffeine, ingested before short-duration, moderate-intensity exercise, would lead to greater circulating concentrations of lactate and IL-6 in a study population comprising both male and female individuals. Methods: Twenty healthy adults (10 men and 10 women age 25 ± 7 yr (mean ± SD)) completed 30 min of moderate-intensity cycle ergometer exercise, at an intensity corresponding to 60% peak oxygen uptake, after ingesting either caffeine (6 mg·kg⁻¹) or placebo. Arterialized-venous blood was collected throughout each of the exercise sessions. Results: Compared with placebo, caffeine increased circulating concentrations of lactate at the end of exercise (5.12 ± 3.67 vs 6.45 ± 4.40 mmol·L⁻¹, P < 0.001) and after 30 min of inactive recovery (1.83 ± 1.59 vs 2.32 ± 2.09 mmol·L⁻¹, P = 0.006). Circulating IL-6 concentrations were greatest after 30 min of inactive recovery (P < 0.001) and higher with caffeine (2.88 ± 2.05 vs 4.18 ± 2.97, pg·mL⁻¹, P < 0.001). Secondary analysis indicated sex differences; caffeine increased the IL-6 response to exercise in men (P = 0.035) but not in women (P = 0.358). Conclusions: In response to moderate-intensity exercise, caffeine evoked greater circulating lactate concentrations in men and women but only increased the IL-6 response to exercise in men. These novel findings suggest that for men unwilling or unable to perform high-intensity and/or long-duration exercise, caffeine may augment the health benefits of relatively short, moderate-intensity exercise.

Background/Objectives: Although the importance of magnesium for overall health and physiological function is well established, its influence on exercise performance is less clear. The primary study objective was to determine the influence of short-term magnesium supplementation on cycle ergometer exercise performance. The hypothesis was that magnesium would elicit an ergogenic effect. Methods: A randomized, double-blind, placebo-controlled, two-period crossover design was used to study men and women who were regular exercisers. Fifteen participants ingested either a placebo or magnesium chloride (MgCl₂ 300 mg) twice per day, for 9 days, separated by a 3-week washout. During days 8 and 9, participants completed a battery of cycle ergometer exercise tests, and whole blood, vastus lateralis, and stools were sampled. The primary outcomes were the maximal oxygen uptake (VO_2max), a simulated 10 km time trial, and the sprint exercise performance. Additional outcomes included skeletal muscle mitochondrial respiration, and, on account of the known laxative effects of magnesium, the gut microbiota diversity. Results: Compared with a placebo, MgCl₂ supplementation increased the circulating ionized Mg concentration (p < 0.03), decreased the VO_2max (44.4 ± 7.7 vs. 41.3 ± 8.0 mL/kg/min; p = 0.005), and decreased the mean power output during a 30 s sprint (439 ± 88 vs. 415 ± 88 W; p = 0.03). The 10 km time trial was unaffected (1282 ± 126 vs. 1281 ± 97 s; p = 0.89). In skeletal muscle, MgCl₂ decreased mitochondrial respiration in the presence of fatty acids at complex II (p = 0.04). There were no significant impacts on the gut microbiota richness (CHAO1; p = 0.68), Shannon’s Diversity (p = 0.23), or the beta-diversity (Bray–Curtis distances; p = 0.74). Conclusions: In summary, magnesium supplementation had modest ergolytic effects on cycle ergometer exercise performance and mitochondrial respiration. We recommend that regular exercisers, free from hypomagnesemia, should not supplement their diet with magnesium.