Dataset Information

The day-to-day reliability of peak fat oxidation and FAT_MAX.

ABSTRACT:

Purpose

Prior studies exploring the reliability of peak fat oxidation (PFO) and the intensity that elicits PFO (FAT_MAX) are often limited by small samples. This study characterised the reliability of PFO and FAT_MAX in a large cohort of healthy men and women.

Methods

Ninety-nine adults [49 women; age: 35 (11) years; [Formula: see text]O₂peak: 42.2 (10.3) mL·kg BM^-1·min^-1; mean (SD)] completed two identical exercise tests (7-28 days apart) to determine PFO (g·min^-1) and FAT_MAX (%[Formula: see text]O₂peak) by indirect calorimetry. Systematic bias and the absolute and relative reliability of PFO and FAT_MAX were explored in the whole sample and sub-categories of: cardiorespiratory fitness, biological sex, objectively measured physical activity levels, fat mass index (derived by dual-energy X-ray absorptiometry) and menstrual cycle status.

Results

No systematic bias in PFO or FAT_MAX was found between exercise tests in the entire sample (- 0.01 g·min^-1 and 0%[Formula: see text]O₂peak, respectively; p > 0.05). Absolute reliability was poor [within-subject coefficient of variation: 21% and 26%; typical errors: ± 0.06 g·min^-1 and × / ÷ 1.26%[Formula: see text]O₂peak; 95% limits of agreement: ± 0.17 g·min^-1 and × / ÷ 1.90%[Formula: see text]O₂peak, respectively), despite high (r = 0.75) and moderate (r = 0.45) relative reliability for PFO and FAT_MAX, respectively. These findings were consistent across all sub-groups.

Conclusion

Repeated assessments are required to more accurately determine PFO and FAT_MAX.

SUBMITTER: Chrzanowski-Smith OJ

PROVIDER: S-EPMC7340634 | biostudies-literature | 2020 Aug

REPOSITORIES: biostudies-literature

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Publications

The day-to-day reliability of peak fat oxidation and FAT<sub>MAX</sub>.

Chrzanowski-Smith Oliver J OJ Edinburgh Robert M RM Thomas Mark P MP Haralabidis Nicos N Williams Sean S Betts James A JA Gonzalez Javier T JT

European journal of applied physiology 20200601 8

<h4>Purpose</h4>Prior studies exploring the reliability of peak fat oxidation (PFO) and the intensity that elicits PFO (FAT<sub>MAX</sub>) are often limited by small samples. This study characterised the reliability of PFO and FAT<sub>MAX</sub> in a large cohort of healthy men and women.<h4>Methods</h4>Ninety-nine adults [49 women; age: 35 (11) years; [Formula: see text]O<sub>2</sub>peak: 42.2 (10.3) mL·kg BM<sup>-1</sup>·min<sup>-1</sup>; mean (SD)] completed two identical exercise tests (7-28 ...[more]

PMID: 32488584

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Project description:PurposeTo provide empirically-supported thresholds for step-based intensity (i.e., peak 30-min cadence; average of the top 30 steps/min in a day) and steps/day in relation to cardiometabolic health outcomes.MethodsReceiver operating characteristic curve analysis was applied to the National Health and Nutrition Examination Survey (NHANES) 2005-2006 accelerometer-derived step data to determine steps/day and peak 30-min cadence as risk screening values (i.e., thresholds) for fasting glucose, body mass index, waist circumference, high blood pressure, triglycerides, and HDL cholesterol. Thresholds for peak 30-min cadence and steps/day were derived that, when exceeded, classify the absence of each cardiometabolic risk factor. Additionally, logistic regression models that included the influence of age and smoking were developed using the sample weights, primary sampling units (PSUs), and stratification variables provided by the NHANES survey. Finally, a decision tree analysis was performed to delineate criteria for at-risk versus healthy populations using cadence bands.ResultsPeak 30-min cadence thresholds across cardiometabolic outcomes ranged from 66-72 steps/min. Steps/day thresholds ranged from 4325-6192 steps/day. Higher thresholds were observed in men compared to women. In men, higher steps/day thresholds were observed in age ranges of 30-39, while in women, higher thresholds were observed in the age-range 50-59 years. Decision trees for classifying being at low risk for metabolic syndrome contained one risk-free leaf at higher cadence bands, specifically for any time accumulated at ≥120 steps/min.ConclusionsMinimum thresholds representing absence of cardiometabolic risk range from 4325-6192 steps/day and 66-72 steps/min for peak 30-min cadence. Any time accumulated at ≥120 steps/min was associated with an absence of cardiometabolic risk. Although based on cross-sectional data, these thresholds represent potentially important and clinically interpretable daily physical activity goals.

Project description:AimsExercise training (ET) has been consistently shown to increase peak oxygen consumption (V̇O2 ) in patients with heart failure with preserved ejection fraction (HFpEF); however, inter-individual responses vary significantly. Because it is unlikely that ET-induced improvements in peak V̇O2 are significantly mediated by an increase in peak heart rate (HR), we aimed to investigate whether baseline peak O2 -pulse (V̇O2 × HR-1 , reflecting the product of stroke volume and arteriovenous oxygen difference), not baseline peak V̇O2 , is inversely associated with the change in peak V̇O2 (adjusted by body weight) following ET versus guideline control (CON) in patients with HFpEF.Methods and resultsThis was a secondary analysis of the OptimEx-Clin (Optimizing Exercise Training in Prevention and Treatment of Diastolic Heart Failure, NCT02078947) trial, including all 158 patients with complete baseline and 3 month cardiopulmonary exercise testing measurements (106 ET, 52 CON). Change in peak V̇O2 (%) was analysed as a function of baseline peak V̇O2 and its determinants (absolute peak V̇O2 , peak O2 -pulse, peak HR, weight, haemoglobin) using robust linear regression analyses. Mediating effects on change in peak V̇O2 through changes in peak O2 -pulse, peak HR and weight were analysed by a causal mediation analysis with multiple correlated mediators. Change in submaximal exercise tolerance (V̇O2 at the ventilatory threshold, VT1) was analysed as a secondary endpoint. Among 158 patients with HFpEF (66% female; mean age, 70 ± 8 years), changes in peak O2 -pulse explained approximately 72% of the difference in changes in peak V̇O2 between ET and CON [10.0% (95% CI, 4.1 to 15.9), P = 0.001]. There was a significant interaction between the groups for the influence of baseline peak O2 -pulse on change in peak V̇O2 (interaction P = 0.04). In the ET group, every 1 mL/beat higher baseline peak O2 -pulse was associated with a decreased mean change in peak V̇O2 of -1.45% (95% CI, -2.30 to -0.60, P = 0.001) compared with a mean change of -0.08% (95% CI, -1.11 to 0.96, P = 0.88) following CON. None of the other factors showed significant interactions with study groups for the change in peak V̇O2 (P > 0.05). Change in V̇O2 at VT1 was not associated with any of the investigated factors (P > 0.05).ConclusionsIn patients with HFpEF, the easily measurable peak O2 -pulse seems to be a good indicator of the potential for improving peak V̇O2 through exercise training. While changes in submaximal exercise tolerance were independent of baseline peak O2 -pulse, patients with high O2 -pulse may need to use additional therapies to significantly increase peak V̇O2 .

Dataset Information

The day-to-day reliability of peak fat oxidation and FAT_MAX.

Purpose

Methods

Results

Conclusion

Publications

The day-to-day reliability of peak fat oxidation and FAT<sub>MAX</sub>.

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Dataset Information

The day-to-day reliability of peak fat oxidation and FATMAX.

Purpose

Methods

Results

Conclusion

Publications

The day-to-day reliability of peak fat oxidation and FAT<sub>MAX</sub>.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets

The day-to-day reliability of peak fat oxidation and FAT_MAX.