Graded Carbohydrate Ingestion up to 120 g·h^-1 Attenuates the Reduction in Critical Power Following 3 h of Moderate-Intensity Exercise in a Dose-Dependent Manner.

Authors

Bernardo R Norte, Mollie M Slinn, Kelsie O Johnson, Elizabeth Mahon, Sam O Shepherd, Juliette A Strauss, Julien B Louis

Published in

Scandinavian journal of medicine & science in sports. Volume 36. Issue 6. Pages e70326.

Abstract

This study examined the effects of graded carbohydrate (CHO) ingestion at rates of 0 (water only), 60 and 120 g·h^-1 (1:0.8 ratio of maltodextrin-to-fructose) on changes in critical power following 3-h of moderate-intensity cycling in endurance-trained cyclists/triathletes (n = 16; V̇O_2max 51.8 ± 6.8 mL·kg^-1·min^-1). Following a standardized 24-h CHO loading protocol (8 g·kg^-1) and pre-exercise meal (2 g·kg^-1), participants completed a 3-min critical power (CP) test, with end-test power (EP) and work done above EP used as estimates of CP and W', respectively, in a non-fatigued state and after 3-h of cycling at 95% gas exchange threshold ('fatigued' state). CP was significantly reduced (p < 0.001) after the 3-h exercise in all experimental conditions (water: 236 ± 30 W; 60 g·h^-1: 257 ± 28 W; 120 g·h^-1: 266 ± 29 W) compared to the non-fatigued state (277 ± 27 W). However, this reduction in CP was attenuated with increasing CHO intake during exercise in a dose-dependent manner, such that CP after 3-h was greater in the 120 g·h^-1 vs. 60 g·h^-1 vs. water condition (p < 0.05). W' declined over time, with no differences between fatigued conditions (p > 0.05). Mean whole-body CHO oxidation rates were significantly higher (p < 0.001) with increasing CHO intake (water: 1.84 ± 0.28; 60 g·h^-1: 2.16 ± 0.15; 120 g·h^-1: 2.31 ± 0.14 g·min^-1). These data suggest that CHO ingestion at 120 g·h^-1 limits the reduction in CP following prolonged moderate-intensity cycling, with no effect on W'. These findings demonstrate that the boundary between heavy- and severe-intensity exercise shifts under fatigue, with CHO availability possibly acting as a key modulator of endurance durability.

PMID:
42322010
Bibliographic data and abstract were imported from PubMed on 20 Jun 2026.

Read full publication at:
Please sign in to see all details.

Stats

1-terrible, 9-excellent. How would you rate this publication? Sign in in to submit your rating.

Post a comment

You need to be signed in to post comments. You can sign in here.

Comments

There are no comments yet.