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Appl Physiol Nutr Metab. 2016 Jul;41(7):719-27. doi: 10.1139/apnm-2015-0526. Epub 2016 Mar 2.

Nighttime feeding likely alters morning metabolism but not exercise performance in female athletes.

Author information

1
a Department of Nutrition, Food, and Exercise Sciences, Institute of Sport Sciences and Medicine, Florida State University, Tallahassee, FL 32306, USA.
2
b Discipline of Biokinetics, Exercise, and Leisure Studies, University of KwaZulu-Natal, Durban 4000, South Africa.
3
c Department of Psychology and Neuroscience, Florida State University, Tallahassee, FL 32306, USA.

Abstract

The timing of morning endurance competition may limit proper pre-race fueling and resulting performance. A nighttime, pre-sleep nutritional strategy could be an alternative method to target the metabolic and hydrating needs of the early morning athlete without compromising sleep or gastrointestinal comfort during exercise. Therefore, the purpose of this investigation was to examine the acute effects of pre-sleep chocolate milk (CM) ingestion on next-morning running performance, metabolism, and hydration status. Twelve competitive female runners and triathletes (age, 30 ± 7 years; peak oxygen consumption, 53 ± 4 mL·kg(-1)·min(-1)) randomly ingested either pre-sleep CM or non-nutritive placebo (PL) ∼30 min before sleep and 7-9 h before a morning exercise trial. Resting metabolic rate (RMR) was assessed prior to exercise. The exercise trial included a warm-up, three 5-min incremental workloads at 55%, 65%, and 75% peak oxygen consumption, and a 10-km treadmill time trial (TT). Physiological responses were assessed prior, during (incremental and TT), and postexercise. Paired t tests and magnitude-based inferences were used to determine treatment differences. TT performances were not different ("most likely trivial" improvement with CM) between conditions (PL: 52.8 ± 8.4 min vs CM: 52.8 ± 8.0 min). RMR was "likely" increased (4.8%) and total carbohydrate oxidation (g·min(-1)) during exercise was "possibly" or likely increased (18.8%, 10.1%, 9.1% for stage 1-3, respectively) with CM versus PL. There were no consistent changes to hydration indices. In conclusion, pre-sleep CM may alter next-morning resting and exercise metabolism to favor carbohydrate oxidation, but effects did not translate to 10-km running performance improvements.

KEYWORDS:

alimentation de nuit; alimentation présommeil; chocolate milk; female; femme; hydratation; hydration; lait au chocolat; metabolism; métabolisme; nighttime feeding; performance; post-prandial; postprandial; pre-sleep nutrition

PMID:
27329516
DOI:
10.1139/apnm-2015-0526
[Indexed for MEDLINE]

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