Energy Metabolism During Exercise at Different Time Intervals Following a Meal*

Willcutts, Kate; Wilcox, Andrew C.; Grunewald, Katharine K.

doi:10.1055/s-2007-1025013

Cited by 9 publications

(11 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It has been shown that fat oxidation, rather than the use of carbohydrate as a substrate, tends to be higher at low-to-moderate intensities of exercise, no >60–65 % VO 2max , but is likely to decrease at an intensity >75 % VO 2max ( 60 , 61 ) . These data corroborate the findings of the present study, in which most of the interventions relating to fat oxidation during exercise included in the meta-analysis were performed with intensities between 40 and 65 % VO 2max ( 30 , 31 , 39 , 41 , 44 , 47 , 51 , 52 ) . Studies that used greater intensities, and where exact values were given in the published report, did not surpass 70 % VO 2max ( 40 , 43 ) .…”

Section: Discussionsupporting

confidence: 91%

“…It is well established in the literature that the contribution of carbohydrate to energy supply increases incrementally with exercise intensity (>65 % VO 2max ), whereas the fat oxidation peak occurs at lower intensities (45-65 % VO 2max ), which may be influenced by sex, training status, VO 2max and diet (60) . The present analysis showed that during exercises at intensities <70 % VO 2max , fat oxidation was higher in the fasted state (approximately 3•45 g), but that there was no difference in this variable between Bergman & Brooks, 1999aBergman & Brooks, 1999bFarah & Gill, 2013Gonzalez et al, 2013Isacco et al, 2012aIsacco et al, 2012bLittle et al, 2010Massicotte et al, 1990Maughan & Gleeson, 1988Paul et al, 1996Whitley et al, 1998Willcutts et al, 1988Wu et al, 2003 fasted and fed states during exercises at intensities ≥70 % VO 2max . These findings confirm the results reported by Bergman & Brooks (30) , in which the effect of intensity and previous feeding on energy substrate used during exercise was verified.…”

Section: Discussionmentioning

confidence: 42%

“…That is, an increase in fat oxidation may also occur in 'fed state' individuals after a certain interval, and may be caused by a reduction in muscle glycogen that occurs in the advanced stages of prolonged exercise (4) . Furthermore, the majority of included studies were conducted with physically active individuals (30,40,41,43,44,47,(50)(51)(52) , and the literature indicates that fat oxidation during sub-maximal exercise is improved with aerobic physical training (14,60) . As exercise intensity can influence the utilisation of energy substrates during exercise, sensitivity analyses were performed according to this criterion.…”

Section: Discussionmentioning

confidence: 99%

“…These data were all requested from authors but were not provided. 'DigitizeIt' software was used to extract the average relating to fat oxidation from one study (44) , relating to NEFA concentrations from fourteen studies (6,7,37,38,(41)(42)(43)(45)(46)(47)(48)(49)(50)(51) , relating to glucose concentrations from sixteen studies (6,7,32,(36)(37)(38)(39)42,(45)(46)(47)(48)(49)(50)(51)(52) and relating to insulin concentrations from thirteen studies (6,7,37,38,43,(45)(46)(47)(48)(49)(50)(51)(52) .…”

Section: Description Of Studiesmentioning

confidence: 99%

“…Fat oxidation. Data on fat oxidation were available from eleven studies (30,31,(39)(40)(41)43,44,47,(50)(51)(52) , with a total of 117 individuals evaluated ( Fig. 4).…”

Section: Effects Of Interventionsmentioning

confidence: 99%

See 4 more Smart Citations

Effects of aerobic exercise performed in fasted v. fed state on fat and carbohydrate metabolism in adults: a systematic review and meta-analysis

et al. 2016

View full text Add to dashboard Cite

This study aimed to verify the effect of aerobic exercise performed in the fasted v. fed states on fat and carbohydrate metabolism in adults. Searches were conducted in March 2015, and updated in July 2016, using PubMed ® , Scopus and Cochrane databases (terms: 'fasting', 'exercise', 'aerobic exercise', 'substrate', 'energy metabolism', 'fat', 'glucose', 'insulin' and 'adult') and references from selected studies. Trials that compared the metabolic effects of aerobic exercise (duration ≤120 min) performed in the fasted v. fed states in adults were accepted. The outcomes evaluated were fat oxidation during exercise and the plasma concentrations of insulin, glucose and NEFA before and immediately after exercise; two independent reviewers extracted the data (A. F. V. and L. C.). The results were presented as weighted mean differences between treatments, with 95 % CI. Of 10 405 articles identified, twenty-seven studies -with a total of 273 participants -were included. There was a significant increase in fat oxidation during exercise performed in the fasted, compared with fed, state (−3·08 g; 95 % CI −5·38, −0·79; I 2 39·1 %). The weighted mean difference of NEFA concentrations was not significantly different between states (0·00 mmol/l; 95 % CI −0·07, 0·08; I 2 72·7 %). However, the weighted mean differences of glucose (0·78 mmol/l; 95 % CI 0·43, 1·14; I 2 90·8 %) and insulin concentrations (104·5 pmol/l; 95 % CI 70·8, 138·2; I 2 94·5 %) were significantly higher for exercise performed in the fed state. We conclude that aerobic exercise performed in the fasted state induces higher fat oxidation than exercise performed in the fed state.

show abstract

Section: Discussionsupporting

confidence: 91%

Section: Discussionmentioning

confidence: 42%

Section: Discussionmentioning

confidence: 99%

Section: Description Of Studiesmentioning

confidence: 99%

“…Fat oxidation. Data on fat oxidation were available from eleven studies (30,31,(39)(40)(41)43,44,47,(50)(51)(52) , with a total of 117 individuals evaluated ( Fig. 4).…”

Section: Effects Of Interventionsmentioning

confidence: 99%

See 3 more Smart Citations

Effects of aerobic exercise performed in fasted v. fed state on fat and carbohydrate metabolism in adults: a systematic review and meta-analysis

et al. 2016

View full text Add to dashboard Cite

show abstract

Factors Influencing Substrate Oxidation During Submaximal Cycling: A Modelling Analysis

2022

View full text Add to dashboard Cite

Background Multiple factors influence substrate oxidation during exercise including exercise duration and intensity, sex, and dietary intake before and during exercise. However, the relative influence and interaction between these factors is unclear. Objectives Our aim was to investigate factors influencing the respiratory exchange ratio (RER) during continuous exercise and formulate multivariable regression models to determine which factors best explain RER during exercise, as well as their relative influence. Methods Data were extracted from 434 studies reporting RER during continuous cycling exercise. General linear mixed-effect models were used to determine relationships between RER and factors purported to influence RER (e.g., exercise duration and intensity, muscle glycogen, dietary intake, age, and sex), and to examine which factors influenced RER, with standardized coefficients used to assess their relative influence. Results The RER decreases with exercise duration, dietary fat intake, age, VO2max, and percentage of type I muscle fibers, and increases with dietary carbohydrate intake, exercise intensity, male sex, and carbohydrate intake before and during exercise. The modelling could explain up to 59% of the variation in RER, and a model using exclusively easily modified factors (exercise duration and intensity, and dietary intake before and during exercise) could only explain 36% of the variation in RER. Variables with the largest effect on RER were sex, dietary intake, and exercise duration. Among the diet-related factors, daily fat and carbohydrate intake have a larger influence than carbohydrate ingestion during exercise. Conclusion Variability in RER during exercise cannot be fully accounted for by models incorporating a range of participant, diet, exercise, and physiological characteristics. To better understand what influences substrate oxidation during exercise further research is required on older subjects and females, and on other factors that could explain additional variability in RER.

show abstract