Hans Braun

• Deutsche Sporthochschule Köln

Relative energy deficiency in sport (RED-S) is a condition that arises from persistent low energy availability (LEA), which affects the hypothalamic–pituitary axis and results in alterations of several hormones in both male and female athletes. As frequent blood hormone status determinations using venipuncture are rare in sports practice, microsamp...

Caffeine is an ergogenic substance that is consumed globally in many forms. The use of buccally absorbable formulations instead of gastrointestinal uptake has become increasingly popular over the years, especially when accelerated absorption with minimal gastrointestinal stress is desired. This study investigated the impact of five different formul...

Despite the availability of nutritional recommendations, studies have reported inadequate nutrition in athletes. The existing literature highlights the importance of the nutritional knowledge of both athletes and coaches in influencing athletes’ food choices and behavior, as well as its direct and indirect impact on athletes’ performance and health...

Vitamin D is crucial to the health and performance of athletes. Although the exact vitamin D requirements for athletes have not been established, maintaining a 25(OH)D level of at least 40 ng/mL is considered beneficial. This randomized controlled intervention study aimed to determine whether an individual loading dose formula for vitamin D supplem...

Vitamin D is crucial for athletes' health and performance. Although the exact vitamin D requirements for athletes have not been established, maintaining 25(OH)D levels of at least 40 ng/ml is considered beneficial. This study aimed to determine whether an individual loading dose formula for vitamin D supplementation is suitable to meet a target val...

The objective of this pilot study was to compare glucose concentrations in capillary blood (CB) samples analysed in a laboratory by a validated method and glucose concentrations measured in the interstitial fluid (ISF) by continuous glucose monitoring (CGM) under different physical activity levels in a postprandial state in healthy athletes without...

INTRODUCTION Continuous glucose monitoring (CGM) has become popular as a supportive tool in diabetic therapy. As CGM devices measure glucose in a minimally invasive manner in the interstitial fluid (ISF) in a frequency of 1 min-1, there is growing interest in the application of CGM systems in professional sports and research of glucose kinetics (Ho...

The objective of this pilot study was to compare glucose concentrations in capillary blood (CB) samples analysed in a laboratory by a validated method and glucose concentrations measured in the interstitial fluid (ISF) by continuous glucose monitoring under different physical activity levels in a postprandial state in healthy and active subjects wi...

Background: An elevated core temperature (Tcore) increases the risk of performance impairments and heat-related illness. Internal cooling (IC) has the potential to lower Tcore when exercising in the heat. The aim of the review was to systematically analyze the effects of IC on performance, physiological, and perceptional parameters. Methods: A syst...

The numbers of vitamin D inadequacies has reportedly increased in the general population, especially in the Northern hemisphere. However, routine measurement of 25(OH) vitamin D is usually associated with a substantial effort due to the requirement of a venous blood sample taken by medical professionals. Thus, the objective of this work is to devel...

Background: The aim was to examine the impact of personal protective equipment (PPE) on human thermoregulation and its alteration in groups of different training status. Methods: 45 men performed a maximum voluntary contraction test in an upright pull position to determine lower body strength and a graded treadmill test to determine maximum oxyg...

This position statement represents the current state of scientific knowledge regarding the recommended fat intake in ambitious recreational and high level sports. It also addresses dietary strategies (fat-loading methods) and food supplements that are designed to influence fat metabolism during physical exercise. No recommendation has so far been e...

This position paper deals with safety aspects of the use of dietary supplements (DS) in sports. DS are legally classified as foodstuffs and may contain vitamins, minerals and other substances with a nutritional or physiological effect. In the case of other substances with a nutritional or physiological effect, it is currently not specifically regul...

This position paper represents the current scientific recommendations for fluid management in sports. Sporting activities should always be commenced with a balanced fluid level (apparent by urine color, which is light yellow in the case of balanced fluid level). The loss of fluids during exercise depends on numerous factors such as the state of exe...

An adequate intake of minerals and vitamins is essential for health and performance of athletes. Depending on the type of sport and the intensity and scope of physical performance, as well as individual factors (such as dietary behavior, perspiration rate and composition of perspiration), athletes may be at increased risk of suboptimal micronutrien...

Athletes expend greater amounts of energy as a result of their training. However, these amounts vary during the competition year and are influenced by such factors as the training period and intensity. Measuring energy expenditure is a complex process that is often achieved through indirect calorimetry. A calculation is possible when certain limita...

Adequate intake of high quality proteins and amino acids is essential for the body in order to build up structures such as muscle, tendons, ligaments and bone. Protein intake also regulates and affects various metabolic processes, including hormonal regulation. Accordingly, proteins and amino acids are, to varying extents, able to stimulate or inhi...

Carbohydrates are an important source of energy during physical exercise. Carbohydrates lead to a higher energy yield and higher energy flux per liter of oxygen than the oxidation of fatty acids. However, the storage capacity for carbohydrates in liver and muscles is limited. Therefore, athletes performing prolonged endurance or intermittent high-i...

Adequate hydration is essential for maintaining health and functionality of the human body. Studies assessing both daily water intake and hydration status are lacking. This study explored data from the European Hydration Research Study (EHRS) and focused on total water intake (TWI), 24 h hydration status, and day-to-day variations in a sample of 57...

Young athletes often face the challenge to meet the recommended nutrient and energy intake for sports performance and development. Training demands vary throughout the season wherefore nutrient intake, especially the carbohydrate (CHO) intake, has to be adjusted in respect to training volume and intensity (Burke 2011). The purpose of this study was...

Purpose: To investigate energy intake, energy expenditure and the nutritional status of young female elite football players using a 7-day food and activity record and blood parameters. Methods: A total of 56 female elite football players (14.8±0.7 yrs) completed the requested food and activity protocols. Misreporting was assessed by the ratio of...

Little is known about whether athletes follow hydration guidelines. The objective of the present study was to assess fluid status in female soccer players in a hot and humid environment, and to assess the effect of an intervention aimed at preventing players from exercising in a dehydrated state. We hypothesized that following the intervention, pla...

Natural stable isotope ratios (δ(15)N) of humans can be used for nutritional analyses and dietary reconstruction of modern and historic individuals and populations. Information about an individual's metabolic state can be obtained by comparison of tissue and dietary δ(15)N. Different methods have been used to estimate dietary δ(15)N in the past; ho...

Creatine is a popular ergogenic supplement in sports nutrition. Yet, supplementation of creatine occasionally caused adverse effects such as gastrointestinal complaints, muscle cramps and an increase in body weight. Creatine monohydrate has already been evaluated by different competent authorities and several have come to the conclusion that a dail...

This study explored the effects of physical activity (PA) and ambient temperature on water turnover and hydration status. Five-hundred seventy three healthy men and women (aged 20-60 years) from Spain, Greece and Germany self-reported PA, registered all food and beverage intake, and collected 24-h urine during seven consecutive days. Fasting blood...

Die Ernährung hat erheblichen Einfluss auf die körperliche und mentale Leistungsfähigkeit und ist für Leistungssportler eine wichtige trainingsbegleitende Maßnahme. Es handelt sich dabei jedoch nicht um eine Ernährungsform, die für alle Sportler in jeder Situation gültig ist. Die Frage nach der optimalen Ernährung benötigt eine Auseinandersetzung m...

Hydration status is linked with health, wellness, and performance. We evaluated hydration status, water intake, and urine output for seven consecutive days in healthy adults. Volunteers living in Spain, Germany, or Greece (n = 573, 39 ± 12 years (51.1% males), 25.0 ± 4.6 kg/m2 BMI) participated in an eight-day study protocol. Total water intake was...

Low energy availability, defined as low caloric intake relative to exercise energy expenditure, has been linked to endocrine alterations frequently observed in chronically energy-deficient exercising women. Our goal was to determine the endocrine effects of low energy availability in exercising men. Six exercising men (VO2peak: 49.3 ± 2.4 ml · kg(-...

Hydration status is linked with health, wellness, and performance. We evaluated hydration status, water intake, and urine output for seven consecutive days in healthy adults. Volunteers living in Spain, Germany, or Greece (n = 573, 39 ± 12 years (51.1% males), 25.0 ± 4.6 kg/m² BMI) participated in an eight-day study protocol. Total water intake was...

Introduction: Hydration status is linked with health, wellness and performance; consequently it is of public health interest to evalua-te hydration status of population groups. Objectives: To evaluate hydration status and water intake and output for 7 consecutive days in healthy adults in summer and winter. Method / Design: Volunteers living in Spa...

Introduction: Daily water turnover depends on climate, body size and composition, fluid ingestion and physical activity among other factors. It is unclear if hydration status in individuals with high levels of physical activity (PA) is compromised due to higher water losses (respiratory, sweating) or is maintained by increased fluid ingestion. Obje...

Introduction: Hydration status is linked with total water intake from food and beverages, but also individual water requirements. It is unclear if drinking behaviour and knowledge influences hydration status in population groups. Objectives: To explore the association between drinking knowledge and hydration status based on total water intake (TWI)...

On April 7-8, 2014, the European Hydration Institute hosted a small group of experts at Castle Combe Manor House, United Kingdom, to discuss a range of issues related to human hydration, health, and performance. The meeting included 18 recognized experts who brought a wealth of experience and knowledge to the topics under review. Eight selected top...

Glycerol is prohibited as a masking agent by the World Anti-Doping Agency and a urinary threshold has recently been recommended. However, little is known about urinary glycerol excretion after exercise, when (1) exogenous glycerol is metabolized increasingly and (2) endogenous glycerol levels are elevated. The purpose of the placebo-controlled cros...

Wie von diversen Fachgesellschaften empfohlen, lasst sich ein bei Sportlern eventuell erhohter Nahrstoffbedarf uber eine ausgewogene Ernahrung abdecken, sodass Nahrungserganzungsmittel (NEM) nur nach einer individuellen Nutzen-Risiko-Analyse eingesetzt werden [18, 34]. Einerseits konnen Nahrungserganzungsmittel, z. B. auf Reisen, bei extremen Unver...

Dietary analysis using δ(15) N values of human remains such as bone and hair is usually based on general principles and limited data sets. Even for modern humans, the direct ascertainment of dietary δ(15) N is difficult and laborious, due to the complexity of metabolism and nitrogen fractionation, differing dietary habits and variation of δ(15) N v...

Fragestellung: Einerseits wird in der Literatur Leistungssport als Risikofaktor für Essstörungen betrachtet, andererseits werden Sport und körperliche Aktivität eine präventive Wirkung auf psychische Störungen und Essstörungen zugeschrieben. Für Studierende mit einem starken Sportbezug ist bisher unklar, welcher Einfluss überwiegt. Daher war es das...

Previous intervention studies suggest that leptin, insulin, insulin-like growth factor 1 (IGF-1), and triiodthyronine (T3) are sensitive markers of inadequate energy intake in relation to exercise expenditures. Because of limitations in metabolic hormone measurements, self-reported energy availability (EA) based on food and activity records may pre...

The misuse of the sympathomimetic and anabolic agent clenbuterol has been frequently reported in professional sport and in the livestock industry. In 2010, a team of athletes returned from competition in China and regular doping control samples were taken within the next two days. All urine samples contained low amounts (pg/ml) of clenbuterol, draw...

Die Einnahme von Nahrungsergänzungsmitteln (NEM) ist in der Bevölkerung und besonders bei Sportlern weit verbreitet. Die Gründe dafür sind z. T. unterschiedlich, liegen aber im Wesentlichen im Bereich von Erhaltung und Unterstützung der Gesundheit, Optimierung der Regeneration und Verbesserung der Leistungsfähigkeit. Unabhängig davon, ob ein NEM di...

During prolonged periods of high energy expenditure (EE), restricted food intake can lead to a loss of body mass. This case study describes the preexpedition support for an unsupported 3-wk crossing of the Atacama Desert in Chile. The goals were to simulate the energy requirements of walking under varying conditions and to predict energy intake and...

The correct assessment of individual energy requirements of athletes remains a challenge. Available literature indicates that accelerometry‐based sensors underestimated energy expenditure in athletes, especially during high‐intensity exercise. The goal of our study was to evaluate two commercially available devices (Actiheart; SenseWear Pro3) durin...

Since 2010, glycerol has been ruled a masking agent by the World Anti-Doping Agency and consequently its administration is prohibited in sports. A detection method is available but little is known about the urinary excretion following administration. Fourteen well-trained cyclists (27.0 ± 5.4 years; O2max: 63.9 ± 8.5 ml/kg/min) were administered gl...

During prolonged periods of high energy expenditure, restricted food intake can lead to a loss of body mass. In this case study we describe the pre-expedition support for an unsupported three-week crossing of the Atacama Desert (Chile). Our goals were to simulate the energy requirements of walking under varying conditions and to predict energy inta...

IntroductionThe dietary supplements marketPrevalence of dietary supplement useCommon sports nutrition supplementsReasons for dietary supplements usageWho recommends dietary supplementsEfficacy of dietary supplementsClassification of dietary supplements: the APRID frameworkSupplement assessment and monitoring in practiceRisks and benefits of dietary...

Practitioners who work with elite athletes know that the pressure and considerable rewards involved with success provide a high level of motivation to look for any safe and legal strategy that might enhance performance, even by small margins. Dietary supplements operate in this space, whether they promise a large performance boost or just create th...

Iron depletion seems to occur more frequently among athletes than in the general population and may affect performance capacity. Only little information is available about the prevalence of iron status abnormalities in young elite athletes and whether iron depletion is associated with gender, sport, age or nutrition- and exercise-related factors in...

The correct assessment of energy expenditure (EE) in athletes is important to ensure that dietary energy intake is sufficient. In general, athletes are individuals with especially high levels of total EE (TEE) and exercise-related EE (ExEE). The SenseWear Pro3 Armband (SWA) is a multisensor device for the individual assessment of EE, but data on th...

The assessment of nutrition and activity in athletes requires accurate and precise methods. The aim of this study was to validate a protocol for parallel assessment of diet and exercise against doubly labelled water, 24-h urea excretion, and respiratory gas exchange. The participants were 14 male triathletes under normal training conditions. Energy...

For athletes, nutrition plays an important role in health and performance. It should be considered that sports may vary strongly with respect to work load between training and competition, which influences nutritional needs. Athletes in weight-class sports like judo, wrestling, boxing, lightweight rowing are not allowed to exceed a weight limit at...

Little is known about the prevalence and motives of supplement use among elite young athletes who compete on national and international levels. Therefore, the current survey was performed to assess information regarding the past and present use of dietary supplements among 164 elite young athletes (16.6 +/- 3.0 years of age). A 5-page questionnaire...

Recently published news regarding food safety in China caused some world-wide disturbance and uncertainty among top athletes and their supporting staff. According to an article in The New York Times, a member of the U.S. Olympic team discovered oversized chicken breast when visiting it Supermarket in Beijing China. More interesting, the chicken con...