Smith J.W.,Gatorade Sports Science Institute |
Pascoe D.D.,Auburn University |
Passe D.H.,Scout Consulting |
Ruby B.C.,University of Montana |
And 3 more authors.
Medicine and Science in Sports and Exercise | Year: 2013
Background: There is a lack of consensus regarding the optimal range of carbohydrate (CHO) ingestion rates recommended for endurance athletes. Purpose: This study investigated the relationship between CHO dose and cycling time trial performance to identify an optimal range of CHO ingestion rates for endurance performance. Methods: Fifty-one cyclists and triathletes (28 ± 7 yr, mean ± SD) across four research sites completed four trials. Each trial consisted of a 2-h constant load ride at 95% of the workload that elicited a 4-mmol·L blood lactate concentration immediately followed by a computer-simulated 20-km time trial, which subjects were asked to complete as quickly as possible. Twelve CHO electrolyte (18 mmol·L-1 Na, 3 mmol·L-1 K, and 11 mmol·L-1 Cl) beverages (three at each site) were tested in a double-blind manner, providing subjects 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, and 120 g CHO (1:1:1 glucose-fructose-maltodextrin) per hour during the 2-h constant load ride at a fluid intake rate of 1 L·h. All subjects also consumed a noncaloric placebo on one counterbalanced test occasion. Data were natural log transformed, subjected to a mixed-model analysis, and are reported as adjusted treatment means. Results: We estimate incremental performance improvements of 1.0%, 2.0%, 3.0%, 4.0%, and 4.7% at 9, 19, 31, 48, and 78 g·h, respectively, with diminishing performance enhancement seen at CHO levels >78 g·h. Conclusions: CHO beverage ingestion and endurance (∼160 min) performance appear to be related in a curvilinear dose-response manner, with the best performance occurring with a CHO (1:1:1 glucose-fructose-maltodextrin) ingestion rate of 78 g·h. © 2012 by the American College of Sports Medicine.
Zhang Y.,Zhejiang University of Science and Technology |
Davis J.-K.,Gatorade Sports Science Institute |
Casa D.J.,University of Connecticut |
Bishop P.A.,University of Alabama
Medicine and Science in Sports and Exercise | Year: 2015
Purpose Cold water immersion (CWI) provides rapid cooling in events of exertional heat stroke. Optimal procedures for CWI in the field are not well established. This meta-analysis aimed to provide structured analysis of the effectiveness of CWI on the cooling rate in healthy adults subjected to exercise-induced hyperthermia. Methods An electronic search (December 2014) was conducted using the PubMed and Web of Science. The mean difference of the cooling rate between CWI and passive recovery was calculated. Pooled analyses were based on a random-effects model. Sources of heterogeneity were identified through a mixed-effects model Q statistic. Inferential statistics aggregated the CWI cooling rate for extrapolation. Results Nineteen studies qualified for inclusion. Results demonstrate CWI elicited a significant effect: mean difference, 0.03°C·min-1; 95% confidence interval, 0.03-0.04°C·min-1. A conservative, observed estimate of the CWI cooling rate was 0.08°C·min-1 across various conditions. CWI cooled individuals twice as fast as passive recovery. Subgroup analyses revealed that cooling was more effective (Q test P < 0.10) when preimmersion core temperature ≥38.6°C, immersion water temperature ≤10°C, ambient temperature ≥20°C, immersion duration ≤10 min, and using torso plus limbs immersion. There is insufficient evidence of effect using forearms/hands CWI for rapid cooling: mean difference, 0.01°C·min-1; 95% confidence interval, -0.01°C·min-1 to 0.04°C·min-1. A combined data summary, pertaining to 607 subjects from 29 relevant studies, was presented for referencing the weighted cooling rate and recovery time, aiming for practitioners to better plan emergency procedures. Conclusions An optimal procedure for yielding high cooling rates is proposed. Using prompt vigorous CWI should be encouraged for treating exercise-induced hyperthermia whenever possible, using cold water temperature (approximately 10°C) and maximizing body surface contact (whole-body immersion). © 2015 by the American College of Sports Medicine.
News Article | October 28, 2016
FoodMinds, an award-winning food and nutrition communications and consulting company, is pleased to welcome Mitch Kanter, PhD as its Chief Science Officer. In his new role, Kanter will work closely with FoodMinds co-founders Laura Cubillos, RD, Bill Layden and Susan Pitman, MA, RD, to advise clients on the critical science and evidentiary issues facing the food, beverage, nutrition, health and wellness sectors. He also will co-lead the Global ExpertBench™, a network of nutrition experts spanning six continents. “Dr. Kanter’s proven track record of success in developing and sustaining effective clinical research and nutrition affairs programs, coupled with his deep insights into the state-of-the-science across multiple food and beverage categories, will be a tremendous asset to our clients and our talented team members,” said FoodMinds co-founder Sue Pitman, MA, RD. Having most recently served as Executive Director of the American Egg Board/Egg Nutrition Center, Dr. Kanter has more than 25 years of experience working for multi-national food companies, including The Quaker Oats/Gatorade Company, General Mills and Cargill. He has served in a variety of roles including Director of the Gatorade Sports Science Institute, and Director of Clinical Nutrition Research and Scientific Communications (Quaker Oats); Director of Health and Nutrition Sciences (General Mills); and Discovery Director, Director of Venturing, and Director of Health and Nutrition (Cargill). Kanter has published numerous articles in scholarly journals, written over 150 articles in health professional and lay-oriented publications, and presented at lay and technical conferences all over the world on topics ranging from nutrition and disease prevention, antioxidant supplementation and health, nutrigenomics, the future of functional foods, and regulatory issues that impact food company health claims. “FoodMinds operates at the intersection of science, communication, public affairs and consumer values,” said Dr. Kanter. “I’m thrilled to have the opportunity to help the team continue to bring value-added insights and programs to our clients, as well as to have a positive impact on public health.” About FoodMinds FoodMinds, a division of PadillaCRT, is a food and nutrition communications and consulting firm that is boldly transforming the way the world thinks about food, nutrition and health. With offices in Chicago, Washington, DC and San Francisco, FoodMinds expertly navigates science, public affairs, consumer values and communications to create breakthrough strategies and help clients tell a better story. The firm has more than 40 employees, including 15 registered dietitians and a PhD, along with a global network of nearly 30 nutrition affairs experts. Over the past year, it expanded its capabilities in Strategic Insights and Issues & Crisis Navigation and continued to grow its global footprint. The winner of the 2013 Holmes Report Boutique Agency of the Year and the 2012 Gold SABRE award in the public affairs category, FoodMinds was named a finalist for PRWeek’s 2015 Small Agency of the Year award and was cited by the 2014 Holmes World PR Report as one of the 10 fastest-growing U.S. PR companies. For more information, visit http://www.foodminds.com. ###
Jeukendrup A.,Gatorade Sports Science Institute |
Jeukendrup A.,University of Birmingham
Sports Medicine | Year: 2014
There have been significant changes in the understanding of the role of carbohydrates during endurance exercise in recent years, which allows for more specific and more personalized advice with regard to carbohydrate ingestion during exercise. The new proposed guidelines take into account the duration (and intensity) of exercise and advice is not restricted to the amount of carbohydrate; it also gives direction with respect to the type of carbohydrate. Studies have shown that during exercise lasting approximately 1 h in duration, a mouth rinse or small amounts of carbohydrate can result in a performance benefit. A single carbohydrate source can be oxidized at rates up to approximately 60 g/h and this is the recommendation for exercise that is more prolonged (2-3 h). For ultra-endurance events, the recommendation is higher at approximately 90 g/h. Carbohydrate ingested at such high ingestion rates must be a multiple transportable carbohydrates to allow high oxidation rates and prevent the accumulation of carbohydrate in the intestine. The source of the carbohydrate may be a liquid, semisolid, or solid, and the recommendations may need to be adjusted downward when the absolute exercise intensity is low and thus carbohydrate oxidation rates are also low. Carbohydrate intake advice is independent of body weight as well as training status. Therefore, although these guidelines apply to most athletes, they are highly dependent on the type and duration of activity. These new guidelines may replace the generic existing guidelines for carbohydrate intake during endurance exercise. © The Author(s) 2014.
Jeukendrup A.E.,Gatorade Sports Science Institute |
Jeukendrup A.E.,University of Birmingham
Current Sports Medicine Reports | Year: 2013
Carbohydrates during exercise can improve exercise performance even when the exercise intensity is high (975%V̇O2max) and the duration relatively short (approximately 1 h), but the underlying mechanisms for the ergogenic effects are different from those during more prolonged exercise. Studies have even shown effects of oral carbohydrate mouth rinses compared to placebo with improvements typically between 2% and 3% during exercise lasting approximately 1 h. The effects appear more profound after an overnight fast, but effects are still present even after ingestion of a meal. Brain imaging studies have identified brain areas involved, and it is likely that the oral carbohydrate mouth rinse results in afferent signals capable of modifying motor output. These effects appear to be specific to carbohydrate and are independent of taste. Further research is warranted to fully understand the separate taste transduction pathways for various carbohydrates as well as the practical implications. © 2013 by the American College of Sports Medicine.
Baker L.B.,Gatorade Sports Science Institute |
Jeukendrup A.E.,Gatorade Sports Science Institute |
Jeukendrup A.E.,University of Birmingham
Comprehensive Physiology | Year: 2014
The objective of this article is to provide a review of the fundamental aspects of body fluid balance and the physiological consequences of water imbalances, as well as discuss considerations for the optimal composition of a fluid replacement beverage across a broad range of applications. Early pioneering research involving fluid replacement in persons suffering from diarrheal disease and in military, occupational, and athlete populations incurring exercise- and/or heat-induced sweat losses has provided much of the insight regarding basic principles on beverage palatability, voluntary fluid intake, fluid absorption, and fluid retention. We review this work and also discuss more recent advances in the understanding of fluid replacement as it applies to various populations (military, athletes, occupational, men, women, children, and older adults) and situations (pathophysiological factors, spaceflight, bed rest, long plane flights, heat stress, altitude/cold exposure, and recreational exercise). We discuss how beverage carbohydrate and electrolytes impact fluid replacement. We also discuss nutrients and compounds that are often included in fluid-replacement beverages to augment physiological functions unrelated to hydration, such as the provision of energy. The optimal composition of a fluid-replacement beverage depends upon the source of the fluid loss, whether from sweat, urine, respiration, or diarrhea/vomiting. It is also apparent that the optimal fluid-replacement beverage is one that is customized according to specific physiological needs, environmental conditions, desired benefits, and individual characteristics and taste preferences. © 2014 American Physiological Society.
Karelis A.D.,University of Quebec at Montréal |
Smith J.E.W.,Gatorade Sports Science Institute |
Passe D.H.,Scout Consulting LLC |
Pronnet F.,University of Montréal
Sports Medicine | Year: 2010
It is well established that carbohydrate (CHO) administration increases performance during prolonged exercise in humans and animals. The mechanism(s), which could mediate the improvement in exercise performance associated with CHO administration, however, remain(s) unclear. This review focuses on possible underlying mechanisms that could explain the increase in exercise performance observed with the administration of CHO during prolonged muscle contractions in humans and animals. The beneficial effect of CHO ingestion on performance during prolonged exercise could be due to several factors including (i) an attenuation in central fatigue; (ii) a better maintenance of CHO oxidation rates; (iii) muscle glycogen sparing; (iv) changes in muscle metabolite levels; (v) reduced exercise-induced strain; and (vi) a better maintenance of excitation-contraction coupling. In general, the literature indicates that CHO ingestion during exercise does not reduce the utilization of muscle glycogen. In addition, data from a meta-analysis suggest that a dose-dependent relationship was not shown between CHO ingestion during exercise and an increase in performance. This could support the idea that providing enough CHO to maintain CHO oxidation during exercise may not always be associated with an increase in performance. Emerging evidence from the literature shows that increasing neural drive and attenuating central fatigue may play an important role in increasing performance during exercise with CHO supplementation. In addition, CHO administration during exercise appears to provide protection from disrupted cell homeostasisintegrity, which could translate into better muscle function and an increase in performance. Finally, it appears that during prolonged exercise when the ability of metabolism to match energy demand is exceeded, adjustments seem to be made in the activity of the NaK pump. Therefore, muscle fatigue could be acting as a protective mechanism during prolonged contractions. This could be alleviated when CHO is administered resulting in the better maintenance of the electrical properties of the muscle fibre membrane. The mechanism(s) by which CHO administration increases performance during prolonged exercise is(are) complex, likely involving multiple factors acting at numerous cellular sites. In addition, due to the large variation in types of exercise, durations, intensities, feeding schedules and CHO types it is difficult to assess if the mechanism(s) that could explain the increase in performance with CHO administration during exercise is(are) similar in different situations. Experiments concerning the identification of potential mechanism(s) by which performance is increased with CHO administration during exercise will add to our understanding of the mechanism(s) of musclecentral fatigue. This knowledge could have significant implications for improving exercise performance. © 2010 Adis Data Information BV. All rights reserved.
De Oliveira E.P.,Federal University of Uberlandia |
Burini R.C.,São Paulo State University |
Jeukendrup A.,Gatorade Sports Science Institute |
Jeukendrup A.,Loughborough University
Sports Medicine | Year: 2014
Gastrointestinal problems are common, especially in endurance athletes, and often impair performance or subsequent recovery. Generally, studies suggest that 30-50 % of athletes experience such complaints. Most gastrointestinal symptoms during exercise are mild and of no risk to health, but hemorrhagic gastritis, hematochezia, and ischemic bowel can present serious medical challenges. Three main causes of gastrointestinal symptoms have been identified, and these are either physiological, mechanical, or nutritional in nature. During intense exercise, and especially when hypohydrated, mesenteric blood flow is reduced; this is believed to be one of the main contributors to the development of gastrointestinal symptoms. Reduced splanchnic perfusion could result in compromised gut permeability in athletes. However, although evidence exists that this might occur, this has not yet been definitively linked to the prevalence of gastrointestinal symptoms. Nutritional training and appropriate nutrition choices can reduce the risk of gastrointestinal discomfort during exercise by ensuring rapid gastric emptying and the absorption of water and nutrients, and by maintaining adequate perfusion of the splanchnic vasculature. A number of nutritional manipulations have been proposed to minimize gastrointestinal symptoms, including the use of multiple transportable carbohydrates, and potentially the use of nutrients that stimulate the production of nitric oxide in the intestine and thereby improve splanchnic perfusion. However, at this stage, evidence for beneficial effects of such interventions is lacking, and more research needs to be conducted to obtain a better understanding of the etiology of the problems and to improve the recommendations to athletes. © The Author(s) 2014.
Williams C.,Loughborough University |
Rollo I.,Gatorade Sports Science Institute
Sports Medicine | Year: 2015
The common pattern of play in ‘team sports’ is ‘stop and go’, i.e. where players perform repeated bouts of brief high-intensity exercise punctuated by lower intensity activity. Sprints are generally 2–4 s long and recovery between sprints is of variable length. Energy production during brief sprints is derived from the degradation of intra-muscular phosphocreatine and glycogen (anaerobic metabolism). Prolonged periods of multiple sprints drain muscle glycogen stores, leading to a decrease in power output and a reduction in general work rate during training and competition. The impact of dietary carbohydrate interventions on team sport performance have been typically assessed using intermittent variable-speed shuttle running over a distance of 20 m. This method has evolved to include specific work to rest ratios and skills specific to team sports such as soccer, rugby and basketball. Increasing liver and muscle carbohydrate stores before sports helps delay the onset of fatigue during prolonged intermittent variable-speed running. Carbohydrate intake during exercise, typically ingested as carbohydrate-electrolyte solutions, is also associated with improved performance. The mechanisms responsible are likely to be the availability of carbohydrate as a substrate for central and peripheral functions. Variable-speed running in hot environments is limited by the degree of hyperthermia before muscle glycogen availability becomes a significant contributor to the onset of fatigue. Finally, ingesting carbohydrate immediately after training and competition will rapidly recover liver and muscle glycogen stores. © 2015, The Author(s).
Tippet M.L.,Gatorade Sports Science Institute |
Stofan J.R.,Gatorade Sports Science Institute |
Lacambra M.,Gatorade Sports Science Institute |
Horswill C.A.,Gatorade Sports Science Institute
Journal of Athletic Training | Year: 2011
Context: Tennis is often played in hot, humid environments, intensifying the thermoregulatory strain placed on the athletes. As a safety measure, some tennis organizations allow for a 10- minute break in play between the second and third sets when environmental conditions are extreme. However, the actual effect of these breaks in reducing core temperature is unknown. Objective: To determine change in core temperature after a 10-minute break in play and assess fluid balance in professional female tennis players during tournament matches in the heat. Design: Cross-sectional study. Setting: A Women's Tennis Association Tour-sanctioned outdoor tournament on hard courts under hot conditions (30.3°C ± 2.3°C). Patients or Other Participants: Seven professional tennis players. Main Outcome Measure(s): Change in core temperature after a 10-minute break in tournament play, fluid intake, and sweat losses during match play. Results: Core temperature was reduced from 38.92°C to 38.67°C (change of -0.25°C ± 0.20°C) when a break was taken (P = .02). Mean sweat rate during match play was 2.0 ± 0.5 L/h. During that time, mean fluid intake was 1.5 ± 0.5 L/h, resulting in a 1.2% ± 1.0% reduction in body mass. Conclusions: Female professional tennis players are subjected to high heat loads during match play in hot environments. However, a 10-minute break in play decreased core temperature in 6 of 7 players by an average of 0.25°C, indicating that the break provides practical benefits in the field. Furthermore, although mean sweat rate in this group of female tennis players was high, most athletes were still able to minimize mass loss to less than 2% of their prematch weight. © by the National Athletic Trainers Association, Inc.