Karsten Koehler

Karsten Koehler
Technical University of Munich | TUM · Faculty of Sport and Health Science

Ph.D.

About

158
Publications
66,991
Reads
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3,083
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Introduction
Our overarching goal is to understand the interactions between diet and exercise and how we can use this knowledge to improve human health and performance. We are particularly interested in the multiple pathways how exercise affects energy balance, and how acute and chronic under- or overeating impact the regulation of body weight, body composition, metabolism, and musculoskeletal health.
Additional affiliations
May 2013 - June 2015
Pennsylvania State University
Position
  • PostDoc Position
April 2006 - April 2013
Deutsche Sporthochschule Köln
Position
  • Research Assistant

Publications

Publications (158)
Article
Full-text available
Background Sprint performance may be crucial for athletes in sprint and endurance sports. In this regard, the maximal glycolytic rate (νLamax) is a variable within Mader’s model of metabolism that is commonly tested in a 15-s all-out sprint test. The product of lactate accumulation (ΔLa) and lactate distribution space approximated by fat-free mass...
Article
Purpose The purpose was to evaluate the individual and combined use of the Low Energy Availability in Females Questionnaire (LEAF-Q) and the Brief Eating Disorder in Athletes Questionnaire (BEDA-Q) to detect clinical indicators associated with Relative Energy Deficiency in Sport (REDs). Methods In this cross-sectional study, 50 female endurance at...
Article
Full-text available
While the effect of time-of-day (morning versus evening) on hormones, lipids and lipolysis has been studied in relation to meals and exercise, there are no studies that have investigated the effects of time-of-day on ice bath induced hormone and lipidome responses. In this crossover-designed study, a group of six women and six men, 26 ± 5 years old...
Article
Full-text available
Background The global prevalence of the metabolic disease Type 2 Diabetes (T2D) is increasing. Risk factors contributing to the development of T2D include overweight and obesity, lack of physical activity (PA), and an unhealthy diet. In addition, the gut microbiota has been shown to affect metabolic regulation. Since T2D is preventable, efforts sho...
Presentation
EINLEITUNG: Sport führt häufig zu einer kompensatorischen Erhöhung der Nahrungsaufnahme. Mögliche Modulatoren der Energiekompensation sind Zeitpunkt und Stoffwechselzustand des Trainings, allerdings werden die Effekte häufig vermischt. Ziel war es die Effekte von Tageszeit (morgens/abends) und Stoffwechselzustand (nüchtern/nicht nüchtern) auf die s...
Preprint
Full-text available
While the effect of time-of-day (morning versus evening) has been studied in relation to meals and exercise, there are no studies that investigate the effects of time-of-day on an ice bath. In this crossover-designed study, we recruited a homogenous group of six women and six men for an ice bath (8–12°C for 5 min) in the morning and evening. Venous...
Article
BACKGROUND: Predicting individual weight loss responses to lifestyle interventions is challenging but might help practitioners and clinicians select the most promising approach for each individual. OBJECTIVE: The primary aim of this study was to develop machine learning models to predict individual weight loss responses using only variables known b...
Article
Full-text available
Exercise has a significant impact on the cardiovascular (CV) health of children and adolescents, with resultant alterations in CV structure and function being evident, even at an early age. Engagement in regular, moderate physical activity (PA) is associated with long-term CV health benefits and a reduced risk of CV disease and mortality later in l...
Article
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Objective This cross-sectional study aimed to investigate the role of low energy availability (LEA) in the interplay between depression and disordered eating/eating disorders (DE/EDs) among female athletes. The International Olympic Committee consensus statement on Relative Energy Deficiency in Sport (REDs) identified depression as both an outcome...
Article
Full-text available
Background & Aims: Adequate energy availability is essential for the body to maintain its physiological functions and achieve optimal health, especially among athletes. Unfortunately, low energy availability (LEA) is common among athletes, and it has been associated with impairments in health and performance. In contrast, an energy-restricted diet...
Article
Full-text available
Aim A 15-s all-out sprint cycle test (i.e., νLamax-test) and the post-exercise change in capillary blood lactate concentration is an emerging diagnostic tool that is used to quantify the maximal glycolytic rate. The goal of this study was to determine the relation between 15 s-work, change in capillary blood lactate concentration (∆La) and body com...
Article
Full-text available
Based on Mader's mathematical model, the rate of capillary blood lactate concentration (νLamax) following intense exercise is thought to reflect the maximal glycolytic rate. We aimed to investigate the reliability of important variables of Mader's model (i.e. power output, lactate accumulation, predominant phosphagen contribution time frames (tPCr)...
Article
Full-text available
Introduction Evidence indicates that sphingolipid accumulation drives complex molecular alterations promoting cardiometabolic diseases. Clinically, it was shown that sphingolipids predict cardiometabolic risk independently of and beyond traditional biomarkers such as low-density lipoprotein cholesterol. To date, little is known about therapeutic mo...
Presentation
OBJECTIVE: Continuous glucose monitoring (CGM) shows promise in optimizing the assessment and monitoring of ingestive activity (IA; i.e., consumption of calorie-containing foods and beverages). We conducted a scoping review of publications examining the performance of CGM-based approaches to automatically detect IA. We aimed to answer three questio...
Article
Full-text available
The German Report Card on Physical Activity for Children and Adolescents 2022 provides a summary and a comprehensive evaluation of physical activity levels and correlated indicators using the Active Healthy Kids Canada grading framework. The 2022 German Report Card, established by the Active Healthy Kids Germany (AHK Germany) expert panel, describe...
Article
Full-text available
Purpose Stable isotope ratios of nitrogen (δ¹⁵N) have previously been shown to increase in human hair during periods of catabolism. The goal of this study was to assess changes in δ¹⁵N in urinary urea (δ¹⁵Nurea) and Δ¹⁵N during a short-term controlled energy deficit. Methods We analyzed samples from 6 recreationally active men (25 ± 1 years, BMI:...
Article
Full-text available
Background Accurate dietary assessment remains a challenge, particularly in free-living settings. Continuous glucose monitoring (CGM) shows promise in optimizing the assessment and monitoring of ingestive activity (IA, i.e., consumption of calorie-containing foods/beverages), and it might enable administering dietary Just-In-Time Adaptive Intervent...
Article
Full-text available
Female endurance athletes are at high risk for developing Relative Energy Deficiency in Sport (REDs), resulting in symptoms such as menstrual dysfunction and gastrointestinal (GI) problems. The primary aim of this study was to investigate effects of the FUEL (Food and nUtrition for Endurance athletes—a Learning program) intervention consisting of w...
Poster
Background Sports nutrition science and practice • In theory, sports nutrition guidelines intend to support health and improve performance by adjusting energy and nutrient intake to sport-specific demands. • In practice, athletes often fail to align dietary intake to sport-specific guidelines, resulting in suboptimal energy and nutrient intake jeo...
Conference Paper
INTRODUCTION: Accessible and effective treatment options are needed to manage obesity and its comorbidities. Commercial weight loss (WL) programs are a potential solution to the lack of available treatment, providing greater access at a lower cost than clinic-based approaches. However, few commercial programs have been rigorously evaluated. We asse...
Conference Paper
INTRODUCTION: Acute fasted morning exercise may help create a greater negative 24-hour energy balance than the same exercise performed after a meal. However, research exploring fasted evening exercise is limited. We aimed to assess the effects of a 6-hour fast before evening exercise on post-exercise energy intake (EI). METHODS: In this crossover...
Conference Paper
Introduction: Competitive amateur triathletes implement high training volumes, putting themselves at increased risk for low energy availability (LEA). Appropriate carbohydrate fueling before, during, and after exercise may help reduce athletes’ risk of LEA and improve training quality and adaptations. The goal of the present study was to assess ass...
Conference Paper
Introduction: Nutritional knowledge has been shown to be one factor influencing nutritional status and diet-related decisions among athletes. Assessing knowledge status allows the identification of knowledge gaps, which can subsequently be addressed during nutritional counseling. This study aimed to assess sports nutrition knowledge of athletes aff...
Article
Relative Energy Deficiency in Sport (REDs) is common among female and male athletes representing various sports at different performance levels, and the underlying cause is problematic low energy availability (LEA). It is essential to prevent problematic LEA to decrease the risk of serious health and performance consequences. This narrative review...
Article
Full-text available
INTRODUCTION: Growing scientific evidence indicates that sphingolipids predict cardiometabolic risk, independently of and beyond traditional biomarkers such as low-density lipoprotein cholesterol. To date, it remains largely unknown if and how exercise, a simple, low-cost, and patient-empowering modality to optimise cardiometabolic health, influenc...
Article
The Constrained Model of Total Energy Expenditure predicts that increased physical activity may not influence total energy expenditure, but instead, induces compensatory energetic savings in other processes. Much remains unknown, however, about concepts of energy expenditure, constraint and compensation in different populations, and it is unclear w...
Article
Full-text available
When less energy is available to consume, people often lose weight, which reduces their overall metabolic rate. Their cellular metabolic rate may also decrease (metabolic adaptation), possibly reflected in physiological and/or endocrinological changes. Reduced energy availability can result from calorie restriction or increased activity energy expe...
Poster
INTRODUCTION: Exercise modulates hunger, food choices, and energy intake both acutely and chronically. However, these effects are highly variable and are affected by both individual characteristics and exercise-dependent factors (i.e., intensity, duration). It is unknown if the effects on hunger, food choices, and energy intake differ by type of ae...
Article
Full-text available
INTRODUCTION: Growing scientific evidence indicates that sphingolipids predict cardiometabolic risk, independently of and beyond traditional biomarkers such as low-density lipoprotein cholesterol. To date, it remains largely unknown if and how exercise, a simple, low-cost, and patient-empowering modality to optimise cardiometabolic health, influenc...
Conference Paper
INTRODUCTION: Energy intake (EI) following exercise is highly individual, resulting in compensatory eating in some individuals. Cycling and running differ in their requirements, so a one-by-one transformation is uncertain. The purpose of the study was to assess the impact of different types of aerobic exercise on post-exercise EI and compensatory E...
Article
Full-text available
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...
Poster
OBJECTIVE: Exercise in the fasted state (overnight fast) shifts fuel utilization towards increased fat oxidation. However, the effects on weight loss are equivocal. While breakfast omission may help reduce 24 h energy intake, we and others have shown that hunger is increased and (partial) compensation of the omitted breakfast occurs at subsequent m...
Article
Energy intake in the post-exercise state is highly variable and compensatory eating - i.e., (over-) compensation of the expended energy via increased post-exercise energy intake - occurs in some individuals but not others. We aimed to identify predictors of post-exercise energy intake and compensation. In a randomized crossover design, 57 healthy p...
Article
Full-text available
Female endurance athletes are considered a high-risk group for developing Relative Energy Deficiency in Sport (REDs). Due to the lack of educational and behavioral intervention studies, targeting and evaluating the effects of the practical daily management of REDs, we developed the Food and nUtrition for Endurance athletes—a Learning (FUEL) program...
Poster
Relative energy deficiency in sports (RED-S) is centered by chronic low energy availability (LEA), with a bidirectional causative relationship with mental health. Aside the well-established link between eating disorders and LEA, exercise addiction (ExA) has been proposed as another independent LEA risk factor. The aim of this investigation was to a...
Article
Full-text available
The prevalence of obesity is increasing worldwide, and excess body weight is associated with a substantially increased risk of adverse health conditions. Exercise supports the prevention and management of obesity; however, when used for weight loss, exercise (even at high volumes) is usually relatively ineffective, frequently producing less weight...
Conference Paper
The competitive season in long-distance triathlon is characterized by increases in training load and volume from off- to peak-season, when athletes enter their primary competition. When athletes fail to meet the increased energy demand through the diet, either unintentionally or in attempts to improve their performance by means of weight loss, they...
Presentation
INTRODUCTION: Exercise is recommended for weight management, yet weight loss from exercise is often less than expected based on measured energy expenditure. This is primarily due to compensatory energy intake, which occurs in most exercisers and overrides the appetite-suppressing effects of acute exercise. Exercising in a fasted state seems to be a...
Article
Full-text available
Objectives The energy intake response to exercise is highly variable and energy (over-) compensation via increased post-exercise energy intake occurs in some individuals but not others. In explorative analyses, we aimed to identify biological and behavioral predictors of post-exercise ad libitum energy intake and whether these predictors differ fro...
Article
Full-text available
Objective To characterize the contributions of the loss of energy-expending tissues and metabolic adaptations to the reduction in resting metabolic rate (RMR) following weight loss. Methods A secondary analysis was conducted on data from the Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy study. Changes in RMR, body comp...
Article
Purpose: Wheelchair athletes experience a reduction in fat-free mass due to the underlying condition and/or muscle disuse. This leads to a lower resting energy expenditure (REE), as well as a lower energy expenditure during exercise or daily activities. Traditional markers of low energy availability (LEA), including amenorrhea and low bone mineral...
Article
Full-text available
Relative energy deficiency in sport (RED-S) is a complex syndrome describing health and performance consequences of low energy availability (LEA) and is common among female endurance athletes. Various underlying causes of LEA have been reported, including disordered eating behavior (DE), but studies investigating the association with exercise addic...
Article
Full-text available
Purpose: Elite rowers have large body dimensions, a high metabolic capacity, and they realize high training loads. These factors suggest a high total energy requirement (TER), due to high exercise energy expenditure (EEE) and additional energetic needs. We aimed to study EEE and intensity related substrate utilization (SU) of elite rowers during ro...
Poster
OBJECTIVE: Energy intake in response to exercise is highly variable. While some individuals show reduced energy intake post-exercise, allowing for an exercise-induced energy deficit, others show increased energy intake, (over-) compensating the expended energy. In an exploratory analysis, we aimed to identify biological and behavioral predictors of...
Poster
Hintergrund: Die Wettkampfvorbereitung auf einen Langdistanztriathlon (typischerweise 3,8/180/42,2 km Schwimmen/ Radfahren/Laufen) geht mit erhöhten Trainingsvolumen einher. Der dadurch erhöhte Energieverbrauch kann das Risiko eines relativen Energiemangels (Relative Energy Deficiency in Sports, RED-S) begünstigen. Ziel dieser Untersuchung war, das...
Preprint
Full-text available
Energy intake in the post-exercise state is highly variable and compensatory eating – i.e., (over‑) compensation of the expended energy via increased post-exercise energy intake – occurs in some individuals but not others. We aimed to identify predictors of post-exercise energy intake and compensation. In a randomized crossover design, 57 healthy p...
Preprint
Full-text available
Purpose Increased nitrogen losses observed during periods of energy deficiency are attributed to increased breakdown of endogenous proteins. Stable nitrogen isotope ratios (δ¹⁵N) measured in human hair have previously been shown to reflect prolonged periods of increased protein breakdown. The goal of this study was to determine whether stable nitro...
Article
Energy is a finite resource that is competitively distributed among the body’s systems and biological processes. During times of scarcity, energetic “trade-offs” may arise if less energy is available than is required to optimally sustain all systems. More immediately essential functions are predicted to be prioritized, even if this necessitates the...
Article
Full-text available
Background: The effect of physical activity and exercise on hunger and satiety has been well-studied in younger adults, but the influence of aging is less understood. While some evidence suggests that acute bouts of exercise induce a compensatory eating drive, long-term activity may improve satiety sensitivity. The objective of this study was to in...
Article
Full-text available
Sirtuins are nicotinamide adenine dinucleotide (NAD+)-dependent deacetylases that regulate numerous pathways such as mitochondrial energy metabolism in the human body. Lower levels of these enzymes were linked to diseases such as diabetes mellitus and were also described as a result of aging. Sirtuins were previously shown to be under the control o...
Article
Full-text available
Short‐term energy deficits impair anabolic hormones and muscle protein synthesis. However, the effects of prolonged energy deficits on resistance training (RT) outcomes remain unexplored. Thus, we conducted a systematic review of PubMed and SportDiscus for randomized controlled trials performing RT in an energy deficit (RT+ED) for ≥3 weeks. We firs...
Preprint
Full-text available
Objective To characterize the contributions of the loss of energy-expending tissues and metabolic adaptations to the reduction in resting metabolic rate (RMR) following weight loss. Methods A secondary analysis was conducted on data from the Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy study. Changes in RMR, body compo...
Article
Full-text available
Energy availability describes the amount of dietary energy remaining for physiological functionality after the energy cost of exercise is deducted. The physiological and hormonal consequences of low energy availability (LEA) are well established, but the impact of LEA on physical activity behavior outside of exercise and, specifically, nonexercise...
Article
Full-text available
Suppression of insulin-like growth factor 1 (IGF-1) and leptin secondary to low energy availability (LEA) may contribute to adverse effects on bone health. Whether a high-protein diet attenuates these effects has not been tested. Seven men completed three five-day conditions operationally defined as LEA (15 kcal kg fat-free mass (FFM)-1 day-1) with...
Article
Full-text available
Although exercise modulates appetite regulation and food intake, it remains poorly understood how exercise impacts decision-making about food. The purpose of the present study was to assess the impact of an acute exercise bout on hypothetical choices related to the amount and timing of food intake. Forty-one healthy participants (22.0 ± 2.6 years;...
Article
Full-text available
Energy availability (EA) is defined as the amount of dietary energy available to sustain physiological function after subtracting the energetic cost of exercise. Insufficient EA due to increased exercise, reduced energy intake, or a combination of both, is a potent disruptor of the endocrine milieu. As such, EA is conceived as a key etiological fac...
Preprint
Although exercise modulates appetite regulation and food intake, it remains poorly understood how exercise impacts decision making about food. The purpose of the present study was to assess the impact of an acute exercise bout on hypothetical choices related to the amount and timing of food intake. Forty-one healthy participants (22.0 ± 2.6 years;...
Article
Full-text available
PurposeWeight loss can result in the loss of muscle mass and bone mineral density. Resistance exercise is commonly prescribed to attenuate these effects. However, the anabolic endocrine response to resistance exercise during caloric restriction has not been characterized.Methods Participants underwent 3-day conditions of caloric restriction (15 kca...
Article
Exercise is commonly utilized for weight loss, yet research has focused less on specific modifications to adipose tissue metabolism. White adipose tissue (WAT) is the storage form of fat, whereas brown adipose tissue (BAT) is a thermogenic tissue whose uncoupling increases energy expenditure. The most established BAT activator is cold exposure, whi...
Article
Full-text available
Objectives Iron depletion is common around the world and among certain risk groups in developed countries. The overall purpose was to test the suitability of a novel plasma collection card for minimally invasive iron status assessment. Methods Twenty participants (10 f/10 m) participated in this cross‐sectional study. Ferritin and hemoglobin were...
Article
Full-text available
Background Extensive research has established a clear positive relationship between physical activity (PA), even in small amounts, and psychological well-being, including benefits for emotional and mental health (e.g., decreased depression). However, little research has examined the relationship between PA and decision-making within emotionally amb...
Preprint
Full-text available
UNSTRUCTURED Introduction: Our goal was to assess the validity of monitoring heart rate (HR) and energy expenditure (EE) while sitting or light-to-vigorous physical activity with four popular wrist worn wearables (Apple Watch Series 4, Polar Vantage V, Garmin Fenix 5, Fitbit Versa). Methods: 25 individuals performed 5-min of sitting, walking and ru...
Article
Full-text available
Background: Physical activity reduces the incidences of noncommunicable diseases, obesity, and mortality, but an inactive lifestyle is becoming increasingly common. Innovative approaches to monitor and promote physical activity are warranted. While individual monitoring of physical activity aids in the design of effective interventions to enhance...
Article
Full-text available
Background: The purpose of this study was to examine relationships among biomarkers of iron status, athletic performance, growth and development, and dietary intakes in pre-adolescent and adolescent male and female athletes. Methods: Two-hundred and forty-nine male (n = 179) (mean ± standard deviation for age = 12.0 ± 2.1 years, height = 156.3 ±...
Book
Link to full text: https://www.mdpi.com/books/pdfview/book/1430