Dataset Information

Caffeine increases maximal fat oxidation during a graded exercise test: is there a diurnal variation?

ABSTRACT:

Background

There is evidence that caffeine increases the maximal fat oxidation rate (MFO) and aerobic capacity, which are known to be lower in the morning than in the afternoon. This paper examines the effect of caffeine intake on the diurnal variation of MFO during a graded exercise test in active men.

Methods

Using a triple-blind, placebo-controlled, crossover experimental design, 15 active caffeine-naïve men (age: 32?±?7?years) completed a graded exercise test four times at seven-day intervals. The subjects ingested 3?mg/kg of caffeine or a placebo at 8?am in the morning and 5?pm in the afternoon (each subject completed tests under all four conditions in a random order). A graded cycling test was performed. MFO and maximum oxygen uptake (VO_2max) were measured by indirect calorimetry, and the intensity of exercise that elicited MFO (Fat_max) calculated.

Results

MFO, Fat_max and VO_2max were significantly higher in the afternoon than in the morning (all P?max by 11.1% (36.9?±?14.4 [placebo] vs. 41.0?±?13.1%, P?=?0.005) in the morning, and by 13.1% (42.0?±?11.6 vs. 47.5?±?10.8%, P?=?0.008) in the afternoon.

Conclusion

These findings confirm the previously reported diurnal variation in the whole-body fat oxidation rate during graded exercise in active caffeine-naïve men, and indicate that the acute ingestion of 3?mg/kg of caffeine increases MFO, Fat_max and VO_2max independent of the time of day.

Trial registration

NCT04320446 . Registered 25 March 2020 - Retrospectively registered.

SUBMITTER: Ramirez-Maldonado M

PROVIDER: S-EPMC7792284 | biostudies-literature | 2021 Jan

REPOSITORIES: biostudies-literature

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Caffeine increases maximal fat oxidation during a graded exercise test: is there a diurnal variation?

Ramírez-Maldonado Mauricio M Jurado-Fasoli Lucas L Del Coso Juan J R Ruiz Jonatan J Amaro-Gahete Francisco J FJ

Journal of the International Society of Sports Nutrition 20210107 1

<h4>Background</h4>There is evidence that caffeine increases the maximal fat oxidation rate (MFO) and aerobic capacity, which are known to be lower in the morning than in the afternoon. This paper examines the effect of caffeine intake on the diurnal variation of MFO during a graded exercise test in active men.<h4>Methods</h4>Using a triple-blind, placebo-controlled, crossover experimental design, 15 active caffeine-naïve men (age: 32 ± 7 years) completed a graded exercise test four times at sev ...[more]

PMID: 33413459

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Project description:Functional assessments of cardiovascular fitness (CVF) are needed to establish animal models of dysfunction, test the effects of novel therapeutics, and establish the cardio-metabolic phenotype of mice. In humans, the graded maximal exercise test (GXT) is a standardized diagnostic for assessing CVF and mortality risk. These tests, which consist of concurrent staged increases in running speed and inclination, provide diagnostic cardio-metabolic parameters, such as, VO2max, anaerobic threshold, and metabolic crossover. Unlike the human-GXT, published mouse treadmill tests have set, not staged, increases in inclination as speed progress until exhaustion (PXT). Additionally, they often lack multiple cardio-metabolic parameters. Here, we developed a mouse-GXT with the intent of improving mouse-exercise testing sensitivity and developing translatable parameters to assess CVF in healthy and dysfunctional mice. The mouse-GXT, like the human-GXT, incorporated staged increases in inclination, speed, and intensity; and, was designed by considering imitations of the PXT and differences between human and mouse physiology. The mouse-GXT and PXTs were both tested in healthy mice (C57BL/6J, FVBN/J) to determine their ability to identify cardio-metabolic parameters (anaerobic threshold, VO2max, metabolic crossover) observed in human-GXTs. Next, theses assays were tested on established diet-induced (obese-C57BL/6J) and genetic (cardiac isoform Casq2-/-) models of cardiovascular dysfunction. Results showed that both tests reported VO2max and provided reproducible data about performance. Only the mouse-GXT reproducibly identified anaerobic threshold, metabolic crossover, and detected impaired CVF in dysfunctional models. Our findings demonstrated that the mouse-GXT is a sensitive, non-invasive, and cost-effective method for assessing CVF in mice. This new test can be used as a functional assessment to determine the cardio-metabolic phenotype of various animal models or the effects of novel therapeutics.

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Dataset Information

Caffeine increases maximal fat oxidation during a graded exercise test: is there a diurnal variation?

Background

Methods

Results

Conclusion

Trial registration

Publications

Caffeine increases maximal fat oxidation during a graded exercise test: is there a diurnal variation?

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