A comparative analysis between the effects of galactose and glucose supplementation on endurance performance

• Published in: International journal of sport nutrition and exercise metabolism 2012-02, Vol.22 (1), p.24-30
• Main Authors: Macdermid, Paul W, Stannard, Stephen, Rankin, Dean, Shillington, David
• Format: Article
• Language: English
• Subjects: Adult; Analysis; Athletic Performance - physiology; Bicycling; Bicycling (racing); Diet Records; Dietary supplements; Dietary Supplements - adverse effects; Double-Blind Method; Endurance; Exercise (intensity); Galactose - administration & dosage; Galactose - adverse effects; Glucose - administration & dosage; Glucose - adverse effects; Heart Rate; Humans; Male; Performance enhancement; Performance-Enhancing Substances - administration & dosage; Performance-Enhancing Substances - adverse effects; Physical Endurance - physiology; Physical Exertion; Physical Fitness - physiology; Time Factors
• ISSN: 1526-484X; 1543-2742
• DOI: 10.1123/ijsnem.22.1.24

To determine beneficial effects of short-term galactose (GAL) supplementation over a 50:50 glucose-maltodextrin (GLUC) equivalent on self-paced endurance cycling performance. On 2 separate occasions, subjects performed a 100-km self-paced time trial (randomized and balanced order). This was interspersed with four 1-km and four 4-km maximal efforts reflecting the physical requirements of racing. Before each trial 38±3 g of GAL or GLUC was ingested in a 6% concentrate fluid form 1 hr preexercise and then during exercise at a rate of 37±3 g/hr. Performance variables were recorded for all 1- and 4-km efforts, all interspersed intervals, and the total 100-km distance. Noninvasive indicators of work intensity (heart rate [HR] and rating of perceived exertion) were also recorded. Times taken to complete the 100-km performance trial were 8,298±502 and 8,509±578 s (p=.132), with mean power outputs of 271±37 and 256±45 W (p=.200), for GAL and GLUC, respectively. Mean HR did not differ (GAL 157±7 and GLUC 157±7 beats/min, p=.886). A main effect of carbohydrate (CHO) type on time to complete 4-km efforts occurred, with no CHO Type×Effort Order interaction observed. No main effect of CHO type or interaction of CHO Type×Sequential Order occurred for 1-km efforts. A 6% GAL drink does not enhance performance time during a self-paced cycling performance trial in highly trained endurance cyclists compared with a formula typically used by endurance athletes but may improve the ability to produce intermediate self-paced efforts.