Determination of the exercise intensity that elicits maximal fat oxidation in individuals with obesity.
Maximal fat oxidation (MFO) and the exercise intensity that elicits MFO (FatMax) are commonly determined by indirect calorimetry during graded exercise tests in both obese and normal-weight individuals. However, no protocol has been validated in individuals with obesity. Thus, the aims were to develop a graded exercise protocol for determination of FatMaxin individuals with obesity, and to test validity and inter-method reliability. Fat oxidation was assessed over a range of exercise intensities in 16 individuals (age: 28 (26-29) years; body mass index: 36 (35-38) kg·m-2; 95% confidence interval) on a cycle ergometer. The graded exercise protocol was validated against a short continuous exercise (SCE) protocol, in which FatMaxwas determined from fat oxidation at rest and during 10 min of continuous exercise at 35%, 50%, and 65% of maximal oxygen uptake. Intraclass and Pearson correlation coefficients between the protocols were 0.75 and 0.72 and within-subject coefficient of variation (CV) was 5 (3-7)%. A Bland-Altman plot revealed a bias of -3% points of maximal oxygen uptake (limits of agreement: -12 to 7). A tendency towards a systematic difference (p = 0.06) was observed, where FatMaxoccurred at 42 (40-44)% and 45 (43-47)% of maximal oxygen uptake with the graded and the SCE protocol, respectively. In conclusion, there was a high-excellent correlation and a low CV between the 2 protocols, suggesting that the graded exercise protocol has a high inter-method reliability. However, considerable intra-individual variation and a trend towards systematic difference between the protocols reveal that further optimization of the graded exercise protocol is needed to improve validity.
a Center for Healthy Aging, Department of Biomedical Sciences, Faculty of Health Science, Xlab, University of Copenhagen, Blegdamsvej 3, DK-2200, Denmark.|b Department for Physiotherapy and Occupational Therapy, Metropolitan University College, Sigurdsgade 26, DK-2200 Copenhagen, Denmark.
Sune
S
Dandanell
a Center for Healthy Aging, Department of Biomedical Sciences, Faculty of Health Science, Xlab, University of Copenhagen, Blegdamsvej 3, DK-2200, Denmark.|b Department for Physiotherapy and Occupational Therapy, Metropolitan University College, Sigurdsgade 26, DK-2200 Copenhagen, Denmark.
Charlotte Boslev
CB
Præst
a Center for Healthy Aging, Department of Biomedical Sciences, Faculty of Health Science, Xlab, University of Copenhagen, Blegdamsvej 3, DK-2200, Denmark.
Stine Dam
SD
Søndergård
a Center for Healthy Aging, Department of Biomedical Sciences, Faculty of Health Science, Xlab, University of Copenhagen, Blegdamsvej 3, DK-2200, Denmark.
Camilla
C
Skovborg
a Center for Healthy Aging, Department of Biomedical Sciences, Faculty of Health Science, Xlab, University of Copenhagen, Blegdamsvej 3, DK-2200, Denmark.|c Department of Geriatrics, Bispebjerg University Hospital, Bispebjerg Bakke 23, DK-2400 Copenhagen, Denmark.
Flemming
F
Dela
a Center for Healthy Aging, Department of Biomedical Sciences, Faculty of Health Science, Xlab, University of Copenhagen, Blegdamsvej 3, DK-2200, Denmark.
Steen
S
Larsen
a Center for Healthy Aging, Department of Biomedical Sciences, Faculty of Health Science, Xlab, University of Copenhagen, Blegdamsvej 3, DK-2200, Denmark.
Jørn Wulff
JW
Helge
D000328:Adult; D001642:Bicycling; D015992:Body Mass Index; D004734:Energy Metabolism; D016552:Ergometry; D015444:Exercise; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D005990:Glycerol / Q000097:blood; D006801:Humans; D050356:Lipid Metabolism; D008066:Lipolysis; D008297:Male; D009765:Obesity / Q000097:blood / Q000378:metabolism / Q000628:therapy*; D010084:Oxidation-Reduction; D010101:Oxygen Consumption; D005082:Physical Exertion; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012727:Sex Characteristics
D005230:Fatty Acids, Nonesterified; D005990:Glycerol
exercise intensity; exercise metabolism; fat metabolism; intensité de l’exercice; lipid metabolism; métabolisme des gras; métabolisme lipidique; métabolisme à l’effort; obesity; obésité