Are Natural Killer Cells Novel Mediators of The Effects of Cannabidiol on Mental Health, Sleep Quantity, Sleep Quality, And Immune Function?

Cannabidiol (CBD) has increased in popularity since the United States Farm Bill legalized hemp production in 2018 and is now projected to become a $24.4 billion dollar industry by 2025. Since its legalization, CBD is thought to be an antiepileptic, anxiolytic, and antipsychotic, as well as an agent to improve mental health, quality of life, aspects of sleep and immune function. However, many of these claims lack scientific evidence. The purpose of this randomized, double blind, placebo-controlled trial was to determine the effects of an 8-week CBD intervention on measures of mental health, sleep quantity, sleep quality, and natural killer cell (NKC) quantity and function. Researchers hypothesized that following an 8-week CBD intervention, participants consuming CBD will experience improvements in measures of mental health, increased sleep quantity and quality, and will have an increased percentage of NKC in peripheral blood, as well as decreases in NKC function determined by a measure of K562 cell viability. Physically active men and women (18-45y) were randomly assigned to placebo (CN, n=12) or CBD (CB, n=15) groups. Participants consumed a capsulized control; coconut derived medium chain triglycerides (MCT; 225mg/day) or CBD (50mg/day with 175mg of MCT) daily for 8 weeks. Before and after the intervention period, participants completed measures of mental health, sleep analysis (FITBIT), body size, body composition (BodPod), a peripheral blood draw, anaerobic fitness (Wingate), aerobic fitness (VO2max), 1 repetition strength testing (1RM). Peripheral blood mononuclear cells (PBMC) were extracted from peripheral blood to determine immune cell population percentages, and natural killer cell (NKC) cytotoxicity. Immune population percentage measures involved, staining the cells with anti-CD3 and anti-CD56 for the determination of NKC (CD3-/CD56+), T cells (CD3+/CD56-) and natural killer T cells (NKT; CD3+/CD56+). NKC cytotoxicity analysis involved co-incubated of PBMC with K562 leukemia cells for 4 hours at ratios of 1:1, 5:1, 10:1, and 20:1 effector: target cell (E:T). K562 cell viability was determined using median fluorescence intensity using a flow cytometer. Data are presented as mean ± standard deviation with significance set at α=0.05. An independent-samples T-test was ran on all outcome measures at the pre intervention time point to ensure homogeneity between groups, and a 2 (group) x 2 (time) analysis of variance (ANOVA) was used to identify any interactions or main effects that occurred throughout the intervention. At the pre intervention time points, there were no significant differences between groups with respect to participant anthropometrics or exercise performance measures (age: 26.1 ± 6.2y; height: 169 ± 8.8cm; weight: 71.6 ± 12.8kg; lean body mass: 55.8 ± 11.3kg; body fat: 21.8 ± 8.3%; Peak Power: 647.8 ± 169.9W; Mean Power: 459.1 ± 121.1W; Anaerobic Fatigue: 56.9 ±7.2%; VO2Peak: 45.0 ± 7.6ml/kg/min; 1RM Squat: 88.2 31.4kg; 1RM Bench:61.43 28.44kg); however, VO2Peak significantly decreased after 8-weeks regardless of intervention group (p=0.038; Pre: 45.05 ± 7.61 Post: 43.75 ± 7.34ml/kg/min). There were no significant differences pre to post intervention between groups in measures of mental health (QOL; Pre: 9.49 ± 1.82 Post:19.81 ± 1.42; PFS; Pre: 3.22 ± 1.58 Post:2.74 ± 1.58; BDI; Pre: 4.56 ± 3.83 Post: 4.44 ± 3.72; GAD-7; Pre: 6.3 ± 6.0 Post: 4.9 ± 4.3), sleep quantity (TST; Pre: 386.75 ± 67.69 Post: 388.92 ± 57.89min) or sleep quality (WE; Pre: 26.44 ± 7.53 Post: 26.16 ± 7.70; SE; Pre: 88.41 ± 1.46 Post: 88.02 ± 1.93%). Furthermore, the fraction of NKC within 1x106 peripheral blood mononuclear cells remained unchanged (Pre: 8.44 ± 5.34% Post: 8.79 ± 4.12%), following the intervention period. Finally, there were no differences in K562 cell viability assessed through mean and median fluorescence intensity of Calcein-AM, following an 8-week CBD intervention. Eight weeks of CBD (50mg/day) did not alter measures of mental health, sleep quantity or quality, NKC percentage in peripheral blood or NKC function. This suggests that CBD may not alter mental health, sleep quantity, sleep quality, NKC percentage in peripheral blood or NKC cytolytic function

Proceedings of the Thirteenth International Society of Sports Nutrition (ISSN) Conference and Expo

Meeting Abstracts: Proceedings of the Thirteenth International Society of Sports Nutrition (ISSN) Conference and Expo Clearwater Beach, FL, USA. 9-11 June 201

Chronic cannabis use and circulating biomarkers of neural health, stress, and inflammation in physically active individuals

Previous research has associated cannabis use with altered circulating neurotrophins and biomarkers of immune health, but these relationships have yet to be fully explored in physically active individuals. The specific aim of this study was to explore the relationships between biomarkers of neural health: nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF), immune health: interleukin 6 (IL-6), c-reactive protein (CRP), and cortisol, as well as the presence of depression, in physically active cannabis users (CU) and non-users (NU). Male and female participants (N=30; CU n=15, NU n=15) provided intravenous blood samples and underwent assessment of body composition, V̇O2max, and depression (Beck Depression Inventory-II (BDI-II)). Samples were analyzed for concentrations of NGF, BDNF, IL-6, CRP, and cortisol using ELISAs. CU and NU were compared using an unpaired t-test. Pearson’s correlation and multiple linear regression were used to evaluate relationships amoung variables. There were no significant differences in body size or composition, V̇O2max, total BDI-II Score, concentrations of NGF, IL-6, CRP, or cortisol between groups. BDNF was significantly lower in CU compared to NU (p=0.02), with a significant negative relationship between BDNF and CRP (p=0.02). Mean concentrations of CRP placed CU at higher risk for cardiovascular disease compared to NU. Total BDI-II score negatively correlated with BDNF (p=0.02) and positively correlated with CRP (p=0.02). • Plasma BDNF was significantly lower in physically active cannabis users compared to non-users. • Cannabis users were classified at moderate risk for CVD based on average circulating CRP compared to low risk for non-users.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Accuracy of Resting Metabolic Rate Prediction Equations in Athletes

The purpose of this study was to determine the accuracy of 5 different resting metabolic rate (RMR) prediction equations in male and female athletes. Twenty-two female (19.7 ± 1.4 years; 166.2 ± 5.5 cm; 63.5 ± 7.3 kg; 49.2 ± 4.3 kg of fat-free mass (FFM); 23.4 ± 4.4 body fat (BF) percent) and 28 male (20.2 ± 1.6 years; 181.9 ± 6.1 cm; 94.5 ± 16.2 kg; 79.1 ± 7.2 kg of FFM; 15.1 ± 8.5% BF) athletes were recruited to participate in 1 day of metabolic testing. Assessments comprised RMR measurements using indirect calorimetry, and body composition analyses using air displacement plethysmography. One-way repeated-measures analysis of variance with follow-up paired t tests were selected to determine differences between indirect calorimetry and 5 RMR prediction equations. Linear regression analysis was used to assess the accuracy of each RMR prediction method. An alpha level of p ≤ 0.05 was used to determine statistical significance. All the prediction equations significantly underestimated RMR while the Cunningham equation had the smallest mean difference (−165 kcals). In men, the Harris-Benedict equation was found to be the best prediction formula with the lowest root-mean-square prediction error value of 284 kcals. In women, the Cunningham equation was found to be the best prediction equation with the lowest root-mean-squared error value of 110 kcals. Resting metabolic rate prediction equations consistently seem to underestimate RMR in male and female athletes. The Harris-Benedict equation seems to be most accurate for male athletes, whereas the Cunningham equation may be better suited for female athletes

Effects of Oral Cannabidiol on Health and Fitness in Healthy Adults: An 8-Week Randomized Trial

Background: There is a lack of research on the effects of cannabidiol (CBD) on health-related fitness, physical activity, cognitive health, psychological wellbeing, and concentrations of C-reactive protein (CRP) in healthy individuals. CBD has potential anti-inflammatory and neuroprotective effects. Methods: This study aimed to investigate the effects of 8 weeks of CBD on the above-mentioned measures in healthy individuals. Forty-eight participants were randomized into two groups receiving either oral capsules of 50 mg of CBD or a calorie-matched placebo daily. Participants completed pre- and post-intervention assessments, including blood draws, body composition, fitness, physical activity, and self-reported surveys. Results: There were no significant differences between groups regarding body composition, aerobic fitness, muscular strength, physical activity, cognitive health, psychological wellbeing, and resting CRP concentrations. However, the placebo group experienced a decline in mean peak power and relative peak power compared to the CBD group. Conclusions: The results suggest that 8 weeks of CBD supplementation may prevent declines in anaerobic fitness over time. However, long-term CBD supplementation may not be beneficial for altering measures of health-related fitness, mental health, and inflammation in healthy individuals

The Effect of Cold Ambient Temperature and Preceding Active Warm-up on Lactate Kinetics in Female Cyclists and Triathletes

The aim of this study was to evaluate the effect of cold ambient temperature on lactate kinetics with and without a preceding warm-up in female cyclists/triathletes. Seven female cyclists/triathletes participated in this study. The randomized, crossover study included 3 experimental visits that comprised the following conditions: (i) thermoneutral temperature (20 °C; NEU); (ii) cold temperature (0 °C) with no active warm-up (CNWU); and (iii) cold temperature (0 °C) with 25-min active warm-up (CWU). During each condition, participants performed a lactate threshold (LT) test followed by a time to exhaustion trial at 120% of the participant’s peak power output (PPO) as determined during prior peak oxygen consumption testing. Power output at LT with CNWU was 10.2% ± 2.6% greater than with NEU, and the effect was considered very likely small (effect size (ES) = 0.59, 95%–99% likelihood). Power output at LT with CNWU was 4.2% ± 5.4% greater than with CWU; however, the effect was likely trivial (ES = 0.25, 75%–95% likelihood). At LT, there were no significant differences between interventions groups in oxygen consumption, blood lactate concentration, heart rate, or rating of perceived exertion. Time to exhaustion at 120% at PPO was 11% longer with CNWU than with CWU (ES = 0.62, respectively), and this effect was likely small. These findings suggest that power output at LT was higher in CNWU compared with NEU. Additionally, time to exhaustion at 120% of PPO was higher in CNWU compared with CWU and no different than NEU; these differences likely result in a small improvement in performance with CNWU versus CWU and NEU.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author