Next Article in Journal
Potential Anticancer Properties of Osthol: A Comprehensive Mechanistic Review
Next Article in Special Issue
Interstitial Glucose and Physical Exercise in Type 1 Diabetes: Integrative Physiology, Technology, and the Gap In-Between
Previous Article in Journal
Associations of Serum 25(OH)D Concentrations with Lung Function, Airway Inflammation and Common Cold in the General Population
Previous Article in Special Issue
Carbohydrates for Soccer: A Focus on Skilled Actions and Half-Time Practices
Article Menu
Issue 1 (January) cover image

Export Article

Open AccessFeature PaperArticle
Nutrients 2018, 10(1), 37; doi:10.3390/nu10010037

Metabolic Responses to Carbohydrate Ingestion during Exercise: Associations between Carbohydrate Dose and Endurance Performance

1
Department of Life Sciences, Faculty of Science and Technology University of Westminster, London W1W 6UW, UK
2
School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham B15 2TT, UK
3
Physiology, Exercise and Nutrition Research Group, Faculty of Health Sciences and Sport, University of Stirling, Stirling FK9 4LA, UK
*
Author to whom correspondence should be addressed.
Received: 30 November 2017 / Revised: 20 December 2017 / Accepted: 25 December 2017 / Published: 3 January 2018
(This article belongs to the Special Issue Carbohydrate Metabolism in Health and Disease)
View Full-Text   |   Download PDF [1212 KB, uploaded 3 January 2018]   |  

Abstract

Carbohydrate (CHO) ingestion during exercise lasting less than three hours improves endurance exercise performance but there is still debate about the optimal dose. We utilised stable isotopes and blood metabolite profiles to further examine metabolic responses to CHO (glucose only) ingestion in the 20–64 g·h−1 range, and to determine the association with performance outcome. In a double-blind, randomized cross-over design, male cyclists (n = 20, mean ± SD, age 34 ± 10 years, mass 75.8 ± 9 kg, peak power output 394 ± 36 W, VO2max 62 ± 9 mL·kg−1·min−1) completed four main experimental trials. Each trial involved a two-hour constant load ride (185 ± 25 W) followed by a time trial, where one of three CHO beverages, or a control (water), were administered every 15 min, providing 0, 20, 39 or 64 g CHO·h−1. Dual glucose tracer techniques, indirect calorimetry and blood analyses were used to determine glucose kinetics, exogenous CHO oxidation (EXO), endogenous CHO and fat oxidation; and metabolite responses. Regression analysis revealed that total exogenous CHO oxidised in the second hour of exercise, and suppression of serum NEFA concentration provided the best prediction model of performance outcome. However, the model could only explain ~19% of the variance in performance outcome. The present data demonstrate that consuming ~40 g·h−1 of CHO appears to be the minimum ingestion rate required to induce metabolic effects that are sufficient to impact upon performance outcome. These data highlight a lack of performance benefit and few changes in metabolic outcomes beyond an ingestion rate of 39 g·h−1. Further work is required to explore dose-response effects of CHO feeding and associations between multiple metabolic parameters and subsequent performance outcome. View Full-Text
Keywords: glucose; fat oxidation; exogenous; fatty acids; hepatic glucose output glucose; fat oxidation; exogenous; fatty acids; hepatic glucose output
Figures

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).

Supplementary material

Share & Cite This Article

MDPI and ACS Style

Newell, M.L.; Wallis, G.A.; Hunter, A.M.; Tipton, K.D.; Galloway, S.D.R. Metabolic Responses to Carbohydrate Ingestion during Exercise: Associations between Carbohydrate Dose and Endurance Performance. Nutrients 2018, 10, 37.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Nutrients EISSN 2072-6643 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top