Bennett, SJ, Tiollier, E, Guibert, E, Morales-Artacho, A, Lalire, P, Owens, DJ, Morton, JP, Brocherie, F and Louis, J (2023) Environmental heat stress offsets adaptation associated with carbohydrate periodization in trained male triathletes. Scandinavian Journal of Medicine and Science in Sports. ISSN 0905-7188
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Bennett et al. 2023 SJMSS (SLTL in the heat).pdf - Published Version Available under License Creative Commons Attribution Non-commercial No Derivatives. Download (5MB) | Preview |
Abstract
Purpose: Carbohydrate (CHO) intake periodization via the sleep low train low (SL-TL) diet–exercise model increases fat oxidation during exercise and may enhance endurance-training adaptation and performance. Conversely, training under environmental heat stress increases CHO oxidation, but the potential of combined SL-TL and heat stress to enhance metabolic and performance outcomes is unknown.
Methods: Twenty-three endurance-trained males were randomly assigned to either control (n = 7, CON), SL-TL (n = 8, SLTemp) or SL-TL + heat stress (n = 8, SLHeat) groups and prescribed identical 2-week cycling training interventions. CON and SLTemp completed all sessions at 20°C, but SLHeat at 35°C. All groups consumed matched CHO intake (6 g·kg−1·day−1) but timed differently to promote low CHO availability overnight and during morning exercise in both SL groups. Submaximal substrate utilization was assessed (at 20°C), and 30-min performance tests (at 20 and 35°C) were performed Pre-, Post-, and 1-week post-intervention (Post+1).
Results: SLTemp improved fat oxidation rates at 60% MAP (~66% VO2peak) at Post+1 compared with CON (p < 0.01). Compared with SLTemp, fat oxidation rates were significantly lower in SLHeat at Post (p = 0.02) and Post+1 (p < 0.05). Compared with CON, performance was improved at Post in SLTemp in temperate conditions. Performance was not different between any groups or time points in hot conditions.
Conclusion: SL-TL enhanced metabolic adaptation and performance compared with CON and combined SL-TL and heat stress. Additional environmental heat stress may impair positive adaptations associated with SL-TL.
Item Type: | Article |
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Uncontrolled Keywords: | Cycling performance; Diet-exercise strategy; Endurance training; Heat acclimation; metabolism; Nutrition; 1106 Human Movement and Sports Sciences; 1116 Medical Physiology; Sport Sciences |
Subjects: | R Medicine > RC Internal medicine > RC1200 Sports Medicine |
Divisions: | Sport & Exercise Sciences |
Publisher: | Wiley |
SWORD Depositor: | A Symplectic |
Date Deposited: | 16 Jun 2023 10:53 |
Last Modified: | 16 Jun 2023 11:00 |
DOI or ID number: | 10.1111/sms.14430 |
URI: | https://researchonline.ljmu.ac.uk/id/eprint/19883 |
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