Showing papers by "Ben Desbrow published in 2020"

Cannabidiol and Sports Performance: a Narrative Review of Relevant Evidence and Recommendations for Future Research

Abstract: Cannabidiol (CBD) is a non-intoxicating cannabinoid derived from Cannabis sativa. CBD initially drew scientific interest due to its anticonvulsant properties but increasing evidence of other therapeutic effects has attracted the attention of additional clinical and non-clinical populations, including athletes. Unlike the intoxicating cannabinoid, Δ9-tetrahydrocannabinol (Δ9-THC), CBD is no longer prohibited by the World Anti-Doping Agency and appears to be safe and well-tolerated in humans. It has also become readily available in many countries with the introduction of over-the-counter “nutraceutical” products. The aim of this narrative review was to explore various physiological and psychological effects of CBD that may be relevant to the sport and/or exercise context and to identify key areas for future research. As direct studies of CBD and sports performance are is currently lacking, evidence for this narrative review was sourced from preclinical studies and a limited number of clinical trials in non-athlete populations. Preclinical studies have observed robust anti-inflammatory, neuroprotective and analgesic effects of CBD in animal models. Preliminary preclinical evidence also suggests that CBD may protect against gastrointestinal damage associated with inflammation and promote healing of traumatic skeletal injuries. However, further research is required to confirm these observations. Early stage clinical studies suggest that CBD may be anxiolytic in “stress-inducing” situations and in individuals with anxiety disorders. While some case reports indicate that CBD improves sleep, robust evidence is currently lacking. Cognitive function and thermoregulation appear to be unaffected by CBD while effects on food intake, metabolic function, cardiovascular function, and infection require further study. CBD may exert a number of physiological, biochemical, and psychological effects with the potential to benefit athletes. However, well controlled, studies in athlete populations are required before definitive conclusions can be reached regarding the utility of CBD in supporting athletic performance.

Sports Dietitians Australia Position Statement: Nutrition for Exercise in Hot Environments

Abstract: It is the position of Sports Dietitians Australia (SDA) that exercise in hot and/or humid environments, or with significant clothing and/or equipment that prevents body heat loss (i.e., exertional heat stress), provides significant challenges to an athlete’s nutritional status, health, and performance. Exertional heat stress, especially when prolonged, can perturb thermoregulatory, cardiovascular, and gastrointestinal systems. Heat acclimation or acclimatization provides beneficial adaptations and should be undertaken where possible. Athletes should aim to begin exercise euhydrated. Furthermore, preexercise hyperhydration may be desirable in some scenarios and can be achieved through acute sodium or glycerol loading protocols. The assessment of fluid balance during exercise, together with gastrointestinal tolerance to fluid intake, and the appropriateness of thirst responses provide valuable information to inform fluid replacement strategies that should be integrated with event fuel requirements. Such strategies should also consider fluid availability and opportunities to drink, to prevent significant under- or overconsumption during exercise. Postexercise beverage choices can be influenced by the required timeframe for return to euhydration and co-ingestion of meals and snacks. Ingested beverage temperature can influence core temperature, with cold/icy beverages of potential use before and during exertional heat stress, while use of menthol can alter thermal sensation. Practical challenges in supporting athletes in teams and traveling for competition require careful planning. Finally, specific athletic population groups have unique nutritional needs in the context of exertional heat stress (i.e., youth, endurance/ultra-endurance athletes, and para-sport athletes), and specific adjustments to nutrition strategies should be made for these population groups.

Effects of probiotics and paraprobiotics on subjective and objective sleep metrics: a systematic review and meta-analysis

Abstract: Inadequate sleep (i.e., duration and/or quality) is becoming increasingly recognized as a global public health issue. Interaction via the gut-brain axis suggests that modification of the gut microbial environment via supplementation with live microorganisms (probiotics) or nonviable microorganisms/microbial cell fractions (paraprobiotics) may improve sleep health. This systematic review and meta-analysis aimed to clarify the effect of consuming probiotics/paraprobiotics on subjective and objective sleep metrics. Online databases were searched from 1980 to October 2019 for studies involving adults who consumed probiotics or paraprobiotics in controlled trials, during which, changes in subjective and/or objective sleep parameters were examined. A total of 14 studies (20 trials) were included in meta-analysis. Random effects meta-analyses indicated that probiotics/paraprobiotics supplementation significantly reduced Pittsburgh Sleep Quality Index (PSQI) score (i.e., improved sleep quality) relative to baseline (−0.78-points, 95% confidence interval: 0.395–1.166; p < 0.001). No significant effect was found for changes on other subjective sleep scales, nor objective parameters of sleep (efficiency/latency) measured using polysomnography or actigraphy. Subgroup analysis for PSQI data suggested that the magnitude of the effect was greater (although not statistically) in healthy participants than those with a medical condition, when treatment contained a single (rather than multiple) strain of probiotic bacteria, and when the duration of treatment was ≥8 weeks. Probiotics/paraprobiotics supplementation may have some efficacy in improving perceived sleep health, measured using the PSQI. While current evidence does not support a benefit of consuming probiotics/paraprobiotics when measured by other subjective sleep scales, nor objective measures of sleep; more studies using well-controlled, within-subject experimental designs are needed.

Muscle fiber typology is associated with the incidence of overreaching in response to overload training

Abstract: The aim of this study was to identify markers of training stress and characteristics of middle-distance runners related to the incidence of overreaching following overload training. Twenty-four highly-trained runners (n=16 male; VO2peak=73.3(4.3) mL·kg·min-1; n=8 female, VO2peak=63.2(3.4) mL·kg·min-1) completed 3 weeks of normal training (NormTr), 3 weeks of high-volume training (HVTr; a 10, 20 and 30% increase in training volume each successive week from NormTr), and a 1-week taper (TapTr; 55% exponential reduction in training volume from HVTr week 3). Before, and immediately after each training period, an incremental treadmill-running test was performed, while resting metabolic rate (RMR), subjective fatigue responses and various resting blood biomarkers were assessed. Muscle fiber typology of the gastrocnemius was estimated by quantification of muscle carnosine using proton magnetic resonance spectroscopy and expressed as a z-score relative to a non-athlete control group. Twelve runners were classified as functionally overreached (FOR) following HVTr (decreased running TTE), whereas the other twelve were classified as acutely fatigued (AF; no decrease in running TTE). The FOR group did not demonstrate systematic alterations in RMR, resting blood biomarkers or submaximal exercise responses compared to the AF group. Gastrocnemius carnosine z-score was significantly higher in FOR (-0.44 ± 0.57) compared to AF (-1.25 ± 0.49, p = 0.004, d = 1.53) and was also associated with changes in running TTE from pre- to post-HVTr (r=-0.55, p=0.005) and pre-HVTr to post-TapTr (r=-0.64, p=0.008). Muscle fiber typology is related to the incidence of overreaching and performance super-compensation following increased training volume and a taper.

Engaging hospitalised patients in their nutrition care using technology: development of the NUTRI-TEC intervention

Abstract: Nutrition is vital for health and recovery during hospitalisation, however most patients fail to meet minimum dietary requirements and up to 50% of patients are malnourished in hospital. When patients participate in nutrition care, their dietary intakes are improved. Advances in health information technology (HIT) have broadened the ways by which patients can participate in care. Our team has developed an innovative, HIT-based intervention (called NUTRI-TEC; engaging patients in their nutrition care using technology), facilitating patient participation in their nutrition care in hospital. This paper aims to describe the systematic and iterative process by which the intervention was developed. NUTRI-TEC development was informed by the Medical Research Council guidance for developing complex interventions and underpinned by theoretical frameworks and concepts (i.e. integrated knowledge translation and patient participation in care), existing evidence and a rigorous program of research. The intervention was co-developed by the multidisciplinary research team and stakeholders, including health consumers (patients), health professionals and industry partners. We used an iterative development and evaluation cycle and regularly tested the intervention with hospital patients and clinicians. The NUTRI-TEC intervention involves active patient participation in their nutrition care during hospitalisation. It has two components: 1) Patient education and training; and 2) Guided nutrition goal setting and patient-generated dietary intake tracking. The first component includes brief education on the importance of meeting energy/protein requirements in hospital; and training on how to use the hospital’s electronic foodservice system, accessed via bedside computer screens. The second component involves patients recording their food intake after each meal on their bedside computer and tracking their intakes relative to their goals. This is supported with brief, daily goal-setting sessions with a health care professional. NUTRI-TEC is a HIT intervention designed to enable patient participation in their nutrition care in hospital. As research on HIT interventions to engage patients in health care in the hospital setting is in its infancy, and as gaps and inconsistencies in the development of such interventions exist, this paper will inform future development of HIT-based interventions in the hospital setting.

Sports nutrition for the recreational athlete.

Abstract: Background Recreational sports participation provides many potential health benefits. However, some athletes experience medical problems associated with, or exacerbated by, a mismanagement of the relationship between their diet and sporting endeavours. Objective The aim of this article is to highlight recent developments in clinical sports nutrition, with a focus on providing evidence-based advice and resources for the management of common medical presentations. Discussion A low dietary energy intake relative to exercise energy demands (ie low energy availability) may result in an array of medical issues. An evidence-based framework for advice on sports supplements is available.

Three consecutive nights of sleep loss: Effects of morning caffeine consumption on subjective sleepiness/alertness, reaction time and simulated driving performance

Abstract: Caffeinated products are often consumed as a popular countermeasure to the effects of sleep loss. However, the efficacy of caffeine to exert these effects after consecutive nights of sleep loss is poorly understood. The aim of this study was to investigate the effects of three consecutive nights of restricted sleep and morning caffeine consumption on subjective ratings of sleepiness/alertness, reaction time, and simulated driving performance. Twenty healthy, habitual caffeine consumers (11 females; age: 23.3 ± 5.7 y; BMI: 22.3 ± 3.5 kg⋅m−2; caffeine intake: 204 ± 89 mg⋅day−1; Mean ± SD) who had normal sleeping patterns (≥8 h⋅night−1) participated in this double-blind, placebo-controlled, randomised study. Following one night of normal sleep (≥8 h time in bed (TIB)), participants underwent three consecutive nights of restricted sleep (5 h TIB). Participants received caffeine (200 mg; n = 10) or placebo (n = 10) capsules each morning and all participants received caffeine (100 mg) capsules each afternoon. Subjective ratings of alertness, concentration and tiredness were measured before and 1 h after morning capsule administration. Choice Reaction Time (CRT) was examined 1 h after morning capsule administration, with response speed and accuracy as outcome variables. Driving performance was assessed using a 30 min simulated driving task, with lateral (standard deviation of lane position [SDLP]; total number of line crossings [LC]) and longitudinal (standard deviation of speed [SDSP]) measures of vehicle control as outcome variables. Alertness and concentration significantly decreased, and tiredness increased across the three days of sleep loss. Caffeine only marginally alleviated these effects. No differences were observed between treatments or across trial days for response speed and accuracy on the CRT task. Likewise, no significant differences were observed between groups or across trial days for any measures of simulated driving performance. Overall, results from this study indicate that three consecutive days of sleep loss influence subjective ratings of alertness, concentration and tiredness, but does not alter CRT or simulated driving performance. Caffeine may alleviate some of the negative subjective effects imposed by restricted sleep, but the efficacy of caffeine to attenuate performance changes in CRT and driving performance were unable to be observed.

Effect of Drinking Rate on the Retention of Water or Milk Following Exercise-Induced Dehydration

Abstract: This study investigated the effect of drinking rate on fluid retention of milk and water following exercise-induced dehydration. In Part A, 12 male participants lost 1.9% ± 0.3% body mass through cycle exercise on four occasions. Following exercise, plain water or low-fat milk equal to the volume of sweat lost during exercise was provided. Beverages were ingested over 30 or 90 min, resulting in four beverage treatments: water 30 min, water 90 min, milk 30 min, and milk 90 min. In Part B, 12 participants (nine males and three females) lost 2.0% ± 0.3% body mass through cycle exercise on four occasions. Following exercise, plain water equal to the volume of sweat lost during exercise was provided. Water was ingested over 15 min (DR15), 45 min (DR45), or 90 min (DR90), with either DR15 or DR45 repeated. In both trials, nude body mass, urine volume, urine specific gravity and osmolality, plasma osmolality, and subjective ratings of gastrointestinal symptoms were obtained preexercise and every hour for 3 hr after the onset of drinking. In Part A, no effect of drinking rate was observed on the proportion of fluid retained, but milk retention was greater (p < .01) than water (water 30 min: 57% ± 16%, water 90 min: 60% ± 20%, milk 30 min: 83% ± 6%, and milk 90 min: 85% ± 7%). In Part B, fluid retention was greater in DR90 (57% ± 13%) than DR15 (50% ± 11%, p < .05), but this was within test–retest variation determined from the repeated trials (coefficient of variation: 17%). Within the range of drinking rates investigated the nutrient composition of a beverage has a more pronounced impact on fluid retention than the ingestion rate.

Hospital Staffs’ Perceptions of Postoperative Nutrition Among Colorectal Patients: A Qualitative Study

Abstract: Background: After lower gastrointestinal surgery, few patients start eating within timeframes outlined by evidence‐based guidelines or meet their nutrition requirements in hospital. The present study explored hospital staffs’ perceptions of factors influencing timely and adequate feeding after colorectal surgery to inform future interventions for improving postoperative nutrition practices and intakes. Methods: This qualitative exploratory study was conducted at an Australian hospital where Enhanced Recovery After Surgery guidelines had not been formally implemented. One‐on‐one semistructured interviews were conducted with hospital staff who provided care to patients undergoing colorectal surgery. Interviews lasted from 21 to 47 minutes and were audio recorded and transcribed verbatim. Data were analyzed using inductive thematic analysis. Emergent themes and subthemes were discussed by all investigators to ensure consensus of interpretation. Results: Eighteen staff participated in interviews, including 9 doctors, 5 nurses, 2 dietitians, and 2 foodservice staff. Staffs’ responses formed 3 themes: (1) variability in perceived acceptability of postoperative feeding; (2) improving dynamics and communication within the treating team; and (3) optimizing dietary intakes with available resources. Conclusion: Staff and organizational factors need to be considered when attempting to improve postoperative nutrition among patients who undergo colorectal surgery. Introducing a feeding protocol, enhancing intraprofessional and interdisciplinary communication, and ensuring the availability of appropriate, nutrient‐dense foods are pivotal to improve nutrition practices and intakes.