Higher dietary carbohydrate content during intensified running training results in better maintenance of performance and mood state

• Published in: Journal of applied physiology (1985) 2004-04, Vol.96 (4), p.1331-1340
• Main Authors: Achten, J, Halson, S. L, Moseley, L, Rayson, M. P, Casey, A, Jeukendrup, A. E
• Format: Article
• Language: English
• Subjects: Adult; Affect - drug effects; Biological and medical sciences; Carbohydrates; Catecholamines - blood; Cross-Over Studies; Diet; Dietary Carbohydrates - administration & dosage; Dose-Response Relationship, Drug; Emotions; Feeding. Feeding behavior; Fundamental and applied biological sciences. Psychology; Heart Rate; Human performance; Humans; Lactic Acid - blood; Lipids - blood; Male; Muscles - physiology; Osmolar Concentration; Pain; Physical Education and Training; Physical Endurance - drug effects; Physical Exertion; Rest; Running; Self Concept; Surveys and Questionnaires; Vertebrates: anatomy and physiology, studies on body, several organs or systems
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/japplphysiol.00973.2003

1 Human Performance Laboratory, School of Sport and Exercise Sciences, University of Birmingham, Edgbaston, B15 2TT Birmingham, United Kingdom; 2 School of Human Movement Studies, Queensland University of Technology, Brisbane, QLD 4001 Queensland, Australia; 3 Optimal Performance, Clifton, BS8 4EJ Bristol, United Kingdom; 4 QinetiQ, Centre for Human Sciences, GU14 OLK Farnborough, United Kingdom Submitted 9 September 2003 ; accepted in final form 26 November 2003 The aim of this study was to determine whether consumption of a diet containing 8.5 g carbohydrate (CHO)·kg -1 ·day -1 (high CHO; HCHO) compared with 5.4 g CHO·kg -1 ·day -1 (control; Con) during a period of intensified training (IT) would result in better maintenance of physical performance and mood state. In a randomized cross-over design, seven trained runners [maximal O 2 uptake ( O 2 max ) 64.7 ± 2.6 ml·kg -1 ·min -1 ] performed two 11-day trials consuming either the Con or the HCHO diet. The last week of both trials consisted of IT. Performance was measured with a preloaded 8-km all-out run on the treadmill and 16-km all-out runs outdoors. Substrate utilization was measured using indirect calorimetry and continuous [U- 13 C]glucose infusion during 30 min of running at 58 and 77% O 2 max . Time to complete 8 km was negatively affected by the IT: time significantly increased by 61 ± 23 and 155 ± 38 s in the HCHO and Con trials, respectively. The 16-km times were significantly increased (by 8.2 ± 2.1%) during the Con trial only. The Daily Analysis of Life Demands of Athletes questionnaire showed significant deterioration in mood states in both trials, whereas deterioration in global mood scores, as assessed with the Profile of Mood States, was more pronounced in the Con trial. Scores for fatigue were significantly higher in the Con compared with the HCHO trial. CHO oxidation decreased significantly from 1.7 ± 0.2 to 1.2 ± 0.2 g/min over the course of the Con trial, which was completely accounted for by a decrease in muscle glycogen oxidation. These findings indicate that an increase in dietary CHO content from 5.4 to 8.5 g CHO·kg -1 ·day -1 (41 vs. 65% total energy intake, respectively) allowed better maintenance of physical performance and mood state over the course of training, thereby reducing the symptoms of overreaching. overtraining; [U- 13 C]glucose; muscle glycogen Address for reprint requests and other correspondence: A. Jeukendrup, School of Sport and Exercise Sciences, Univ. of Birmi