Comparison of indirect calorimetry and a new breath 13C/12C ratio method during strenuous exercise

1992 ◽  
Vol 263 (1) ◽  
pp. E64-E71 ◽  
Author(s):  
J. A. Romijn ◽  
E. F. Coyle ◽  
J. Hibbert ◽  
R. R. Wolfe
Keyword(s):  
Indirect Calorimetry ◽  
Fat Oxidation ◽  
Substrate Oxidation ◽  
Co2 Production ◽  
Strenuous Exercise ◽  
Ratio Method ◽  
O2 Uptake ◽  
Underlying Assumption ◽  
Oxidation Rates

A new stable isotope method for the determination of substrate oxidation rates in vivo is described and compared with indirect calorimetry at rest and during high-intensity exercise (30 min at 80-85% maximal O2 uptake capacity) in six well-trained cyclists. This method uses the absolute ratios of 13C/12C in expired air, endogenous glucose, fat, and protein in addition to O2 consumption and is independent of CO2 production (VCO2). Carbohydrate and fat oxidation rates at rest, calculated by both methods, were not significantly different. During exercise the breath 13C/12C ratio increased and reached a steady state after 15-20 min. Carbohydrate oxidation rates during exercise were 39.4 +/- 5.2 and 41.7 +/- 5.7 mg.kg-1.min-1 [not significant (NS)], and fat oxidation rates were 7.3 +/- 1.3 and 6.9 +/- 1.2 mg.kg-1.min-1 (NS), using indirect calorimetry, and the breath ratio method, respectively. We conclude that the breath 13C/12C ratio method can be used to calculate substrate oxidation under different conditions, such as the basal state and exercise. In addition, the results obtained by this new method support the validity of the underlying assumption that indirect calorimetry regards VCO2 as a reflection of tissue CO2 production, during exercise in trained subjects, even up to 80-85% maximal O2 uptake.

scholarly journals Calculation of substrate oxidation rates in vivo from gaseous exchange

1983 ◽  
Vol 55 (2) ◽  
pp. 628-634 ◽  
Author(s):  
K. N. Frayn
Keyword(s):  
Ketone Bodies ◽  
Fat Oxidation ◽  
Nitrogen Excretion ◽  
Co2 Production ◽  
Gaseous Exchange ◽  
Oxidation Rates ◽  
The Difference ◽  
Urinary Nitrogen Excretion ◽  
Urinary Nitrogen

This paper reviews the assumptions involved in calculating rates of carbohydrate and fat oxidation from measurements of O2 consumption, CO2 production, and urinary nitrogen excretion. It is shown that erroneous results are obtained in the presence of metabolic processes such as lipogenesis and gluconeogenesis. The apparent rates calculated under these conditions can, however, be interpreted as net rates of “utilization.” Thus the apparent rate of carbohydrate oxidation is the sum of the rates of utilization for oxidation and for lipogenesis minus the rate at which carbohydrate is formed from amino acids. The apparent rate of fat oxidation is the difference between the rates of oxidation and synthesis from carbohydrate, so that the apparently negative rates encountered in patients infused with glucose do quantitatively represent net rates of synthesis. Other processes such as synthesis of ketone bodies or lactate at rates greater than their utilization can also disturb the calculations, but the magnitude of the effect can be estimated from appropriate measurements. Methods of correcting the observed gaseous exchange in these circumstances are given.

Substrate oxidation during exercise in taekwondo athletes: impact of aerobic fitness status

2020 ◽  
Vol 16 (5) ◽  
pp. 371-376
Author(s):  
B. Taati ◽  
H. Rohani
Keyword(s):  
Aerobic Fitness ◽  
Oxidation Rate ◽  
Fat Oxidation ◽  
Potential Effect ◽  
Substrate Oxidation ◽  
Training Experience ◽  
Male Athletes ◽  
Fitness Level ◽  
Oxidation Rates ◽  
Maximal Fat Oxidation

The present study aimed to investigate the potential effect of different aerobic fitness levels on substrate oxidation in trained taekwondo athletes. 57 male athletes (age 21.10±7.79 years; VO2max 50.67±6.67 ml/kg/min) with regular weekly taekwondo training and training experience of at least three years completed a graded exercise test to exhaustion on a treadmill. Maximal fat oxidation (MFO), the exercise intensity related to MFO (Fatmax), and carbohydrate (CHO) oxidation rate were measured using indirect calorimetry methods. The athletes then were divided into a low (<50 ml/kg/min, n=18) and high (>50 ml/kg/min, n=39) VO2max group. The average MFO was higher in the high VO2max group than in the low VO2max group (0.46±0.19 vs 0.28±0.11 g/min; P<0.001). Although Fatmax tended toward higher values in the high VO2max group, no difference was observed between the groups (49.15±15.22 vs 42.42±12.37% of VO2max; P=0.18). It was also shown that the high VO2max group had a lower CHO oxidation rate and a higher fat oxidation rate at given exercise intensities. In conclusion, it seems that MFO and substrate oxidation rates in taekwondo athletes can be influenced by aerobic fitness level such that the athletes with higher VO2max appeared to use more fat as a fuel source for energy supply during a given exercise.

scholarly journals The acute effects of olive oil v. cream on postprandial thermogenesis and substrate oxidation in postmenopausal women

2004 ◽  
Vol 91 (2) ◽  
pp. 245-252 ◽  
Author(s):  
M. J. Soares ◽  
S. J. Cummings ◽  
J. C. L. Mamo ◽  
M. Kenrick ◽  
L. S. Piers
Keyword(s):  
Olive Oil ◽  
Postmenopausal Women ◽  
Paired Comparison ◽  
Virgin Olive Oil ◽  
Fat Oxidation ◽  
Extra Virgin Olive Oil ◽  
Substrate Oxidation ◽  
Oxidation Rates ◽  
Diet Induced Thermogenesis ◽  
Postprandial Thermogenesis

The influence of the source of dietary fat on postprandial thermogenesis and substrate oxidation rates, was examined in twelve postmenopausal women aged 57–73 years, with BMI 21·9–38·3 kg/m2. A single blind, randomised, paired comparison of two high-fat, isoenergetic, mixed test meals was conducted. The major source of fat was either cream (CREAM) or extra virgin olive oil (EVOO). RMR, diet-induced thermogenesis (DIT) and substrate oxidation rates over 5 h were measured by indirect calorimetry. There were no differences in body weight, RMR, fasting carbohydrate or fat oxidation rates between the two occasions. DIT (EVOO 97 (sd 46) v. CREAM 76 (sd 69) kJ/5 h and EVOO 5·2 (sd 2·5) v. CREAM 4·1 (sd 3·7)% energy) did not differ between the two test meals. The postprandial increase in carbohydrate oxidation rates, relative to their respective fasting values (ΔCOX), was significantly lower following the EVOO meal (EVOO 10·6 (sd 8·3) v. CREAM 17·5 (sd 10) g/5 h; paired t test, P=0·023), while postprandial fat oxidation rates (ΔFOX) were significantly higher (EVOO 0·0 (sd 4·4) v. CREAM -3·6 (sd 4·0) g/5 h; P=0·028). In the eight obese subjects, however, DIT was significantly higher following the EVOO meal (EVOO 5·1 (sd 2·0) v. CREAM 2·5 (sd 2·9) %; P=0·01). This was accompanied by a significantly lower ΔCOX (EVOO 10·9 (sd 9·9) v. CREAM 17·3 (sd 10·5) g/5 h; P=0·03) and significantly higher ΔFOX (EVOO 0·11 (sd 4·4) v. CREAM −4·1 (sd 4·5) g/5 h, P=0·034). The present study showed that olive oil significantly promoted postprandial fat oxidation and stimulated DIT in abdominally obese postmenopausal women.

Abstract P125: Multiple Measures of Energy Expenditure and Substrate Oxidation in Non-obese White and African American Young Adults

Circulation ◽  
2018 ◽  
Vol 137 (suppl_1) ◽  
Author(s):  
Peter T Katzmarzyk ◽  
Eric Ravussin
Keyword(s):  
Physical Activity ◽  
Energy Expenditure ◽  
Fat Oxidation ◽  
Substrate Oxidation ◽  
Activity Level ◽  
Fat Free Mass ◽  
Free Living ◽  
Multiple Measures ◽  
Oxidation Rates ◽  
Increased Risk

Introduction: African Americans (AA) experience higher rates of obesity and related disorders than the general U.S. population. It has been hypothesized that the increased risk of obesity among AA may be explained, in part, by lower levels of energy expenditure (EE) and lower levels of fat oxidation. However, many different measures of EE and substrate oxidation have been employed across previous studies. Objective: The objective of this study was to compare multiple measures of EE and substrate oxidation among White (W) and AA adults. We hypothesize that AA will have lower EE and lower fat oxidation rates than W. Methods: A sample of 12 young (ages 22 to 35 y), non-obese AA adults was recruited from the local community and pair-matched by age, sex and body mass index (BMI) to a sample of 12 W adults. Height and weight were measured and BMI was calculated (kg/m 2 ). Total fat mass (FM) and fat free mass (FFM) were measured using dual energy x-ray absorptiometry. Resting EE (REE) and respiratory quotient (RQ) were measured in a fasting state using a metabolic cart; 24-hour EE, 24-h RQ, sleep EE and sleep RQ were measured in a whole room calorimeter; and free-living total daily EE (TDEE) was measured over two weeks using doubly labelled water. Physical activity level (PAL) was computed as TDEE/REE. Differences between W and AA were determined using general linear models, adjusting for FFM. Results: The analytic sample had a mean age of 27.0 y (SD 4.3 y) and mean BMI of 22.9 kg/m 2 (SD 2.9 kg/m 2 ). There were no significant differences in age, BMI, FM or FFM between W and AA (all p>0.05). However, W had significantly higher REE (1459 vs 1305 kcal/day; p=0.001), 24-h EE (1826 versus 1737 kcal/day; p=0.02), sleep EE (1509 vs 1405 kcal/day; p=0.005); but not TDEE (2452 vs 2313 kcal/day; p=0.30) compared to AA. There were no race differences in RQ (0.83 vs 0.83; p=0.93), 24-h RQ (0.86 vs 0.88; p=0.24) or sleep RQ (0.86 vs 0.87; p=0.44). On the other hand, AA had higher PAL (1.34 vs 1.26; p=0.04) compared to W. Conclusions: Non-obese W adults demonstrated higher REE, 24-h EE, and sleep EE compared to AA, but had similar levels of free-living TDEE. It appears as though some AA adults may compensate for lower REE by increased physical activity, which may be an effective strategy to prevent weight gain and obesity.

scholarly journals Reduced heart size and increased myocardial fuel substrate oxidation in ACC2 mutant mice

2008 ◽  
Vol 295 (1) ◽  
pp. H256-H265 ◽  
Author(s):  
M. Faadiel Essop ◽  
Heidi S. Camp ◽  
Cheol Soo Choi ◽  
Saumya Sharma ◽  
Ryan M. Fryer ◽  
...  
Keyword(s):  
Target Genes ◽  
Ex Vivo ◽  
Systolic Function ◽  
Substrate Oxidation ◽  
Left Ventricular ◽  
Pyruvate Dehydrogenase Kinase ◽  
Mutant Mice ◽  
Oxidation Rates ◽  
Mitochondrial Fatty Acid

The cardiac-enriched isoform of acetyl-CoA carboxylase (ACC2) is a key regulator of mitochondrial fatty acid (FA) uptake via carnitine palmitoyltransferase 1 (CPT1). To test the hypothesis that oxidative metabolism is upregulated in hearts from animals lacking ACC2 (employing a transgenic Acc2-mutant mouse), we assessed cardiac function in vivo and determined rates of myocardial substrate oxidation ex vivo. When examined by echocardiography, there was no difference in systolic function, but left ventricular mass of the Acc2-mutant (MUT) mouse was significantly reduced (∼25%) compared with wild-types (WT). Reduced activation of the mammalian target of rapamycin (mTOR) and its downstream target p70S6K was found in MUT hearts. Exogenous oxidation rates of oleate were increased ∼22%, and, unexpectedly, exogenous glucose oxidation rates were also increased in MUT hearts. Using a hyperinsulinemic-euglycemic clamp, we found that glucose uptake in MUT hearts was increased by ∼83%. Myocardial triglyceride levels were significantly reduced in MUT vs. WT while glycogen content was the same. In parallel, transcript levels of PPARα and its target genes, pyruvate dehydrogenase kinase-4 (PDK-4), malonyl-CoA decarboxylase (MCD), and mCPT1, were downregulated in MUT mice. In summary, we report that 1) Acc2-mutant hearts exhibit a marked preference for the oxidation of both glucose and FAs coupled with greater utilization of endogenous fuel substrates (triglycerides), 2) attenuated mTOR signaling may result in reduced heart sizes observed in Acc2-mutant mice, and 3) Acc2-mutant hearts displayed normal functional parameters despite a significant decrease in size.

scholarly journals Placebo Effect of Caffeine on Substrate Oxidation during Exercise

Nutrients ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 782
Author(s):  
Jorge Gutiérrez-Hellín ◽  
Carlos Ruiz-Moreno ◽  
Millán Aguilar-Navarro ◽  
Alejandro Muñoz ◽  
David Varillas-Delgado ◽  
...  
Keyword(s):  
Placebo Effect ◽  
Oxidation Rate ◽  
Fat Oxidation ◽  
Substrate Oxidation ◽  
Caffeine Intake ◽  
Similar Degree ◽  
Double Blind ◽  
Oxidation Rates ◽  
Maximal Fat Oxidation ◽  
Trial Participants

By using deceptive experiments in which participants are informed that they received caffeine when, in fact, they received an inert substance (i.e., placebo), several investigations have demonstrated that exercise performance can be enhanced to a similar degree as a known caffeine dose. This ‘placebo effect’ phenomenon may be part of the mechanisms explaining caffeine’s ergogenicity in exercise. However, there is no study that has established whether the placebo effect of caffeine is also present for other benefits obtained with acute caffeine intake, such as enhanced fat oxidation during exercise. Therefore, the aim of this investigation was to investigate the placebo effect of caffeine on fat oxidation during exercise. Twelve young men participated in a deceptive double-blind cross-over experiment. Each participant completed three identical trials consisting of a step incremental exercise test from 30 to 80% of V.O2max. In the two first trials, participants ingested either 3 mg/kg of cellulose (placebo) or 3 mg/kg of caffeine (received caffeine) in a randomized order. In the third trial, participants were informed that they had received 3 mg/kg of caffeine, but a placebo was provided (informed caffeine). Fat oxidation rates were derived from stoichiometric equations. In received caffeine, participants increased their rate of fat oxidation over the values obtained with the placebo at 30%, 40%, 50%, and 60% of V.O2max (all p < 0.050). In informed caffeine, participants increased their rate of fat oxidation at 30%, 40%, 50% 60%, and 70% of V.O2max (all p < 0.050) over the placebo, while there were no differences between received versus informed caffeine. In comparison to placebo (0.32 ± 0.15 g/min), the rate of maximal fat oxidation was higher in received caffeine (0.44 ± 0.22 g/min, p = 0.045) and in informed caffeine (0.41 ± 0.20 g/min, p = 0.026) with no differences between received versus informed caffeine. However, the intensity at which maximal fat oxidation rate was obtained (i.e., Fatmax) was similar in placebo, received caffeine, and informed caffeine trials (42.5 ± 4.5, 44.2 ± 9.0, and 41.7 ± 10.5% of V.O2max, respectively, p = 0.539). In conclusion, the expectancy of having received caffeine produced similar effects on fat oxidation rate during exercise than actually receiving caffeine. Therefore, the placebo effect of caffeine is also present for the benefits of acute caffeine intake on substrate oxidation during exercise and it may be used to enhance fat oxidation during exercise in participants while reducing any risks to health that this substance may have.

Effects of glucose-to-lipid ratio and type of lipid on substrate oxidation rate in patients

1994 ◽  
Vol 267 (5) ◽  
pp. E775-E780 ◽  
Author(s):  
B. Delafosse ◽  
J. P. Viale ◽  
S. Tissot ◽  
S. Normand ◽  
C. Pachiaudi ◽  
...  
Keyword(s):  
Oxidation Rate ◽  
Minute Ventilation ◽  
Caloric Intake ◽  
Carbon Dioxide Production ◽  
Substrate Oxidation ◽  
Co2 Production ◽  
Oxidation Rates ◽  
Lipid Ratios ◽  
Mass Spectrometer System ◽  
Spectrometer System

This study is an investigation into the effects of different carbohydrate-to-lipid ratios on CO2 production in postoperative patients and the determination of the substrate oxidation rates induced by long-chain triglycerides (LCT) or a mixture of long- and medium-chain triglycerides (MCT/LCT) at various carbohydrate-to-lipid ratios. Two groups of eight patients randomly received either LCT or MCT/LCT emulsions. Total caloric intake was set at the measured energy expenditure provided at three different glucose-to-lipid ratios (70:30, 50:50, 30:70). We used long-term indirect calorimetry with a mass spectrometer system and measurement of natural enrichment in 13C of expired CO2 and plasma glucose. The carbon dioxide production and minute ventilation were not different among the different glucose-to-lipid ratios, whatever the type of lipid. Increasing the lipid supply up to 70% of nonprotein caloric intake led to an only minor increase in lipid oxidation rate and thus to a net fat deposit. We conclude that large amounts of lipid (LCT or MCT/LCT) were not of interest in such patients.

scholarly journals The Acute Effect of a Single Exhaustive Sprint Exercise Session on Post-Exercise Fat Oxidation Rate

2018 ◽  
Vol 10 (1) ◽  
pp. 118-126
Author(s):  
Zübeyde Aslankeser ◽  
Şükrü Serdar Balcı
Keyword(s):  
Energy Expenditure ◽  
Oxidation Rate ◽  
Fat Oxidation ◽  
Substrate Oxidation ◽  
Exhaustive Exercise ◽  
Exercise Session ◽  
Post Exercise ◽  
Sprint Exercise ◽  
Oxidation Rates ◽  
Study Results

Abstract It is well known that substrate oxidation rates are increased by exercise. The present study had two main objectives: firstly, to examine the effect of a single exhaustive exercise session on post-exercise substrate oxidation and energy expenditure; and secondly, to determine the differences between athletes and non-athletes.Material and methods: Eighteen healthy male athletes (mean ± SD age; 19.38 ± 2.26 years, VO2max; 60.57 ± 3.90 ml · kg-1 · min-1, n = 8) and non-athletes (age; 20.30 ± 1.26 years, VO2max; 44.97 ± 5.43 ml · kg-1 ·min-1, n = 10) volunteered to participate in the study. After an overnight fast, subjects performed a single sprint exercise session on a cycle ergometer with individual loads (0.075 kg per body weight) until volitional exhaustion. Energy expenditure (EE) and the substrate oxidation rate were measured at rest and during the post-exercise recovery period using indirect calorimetry. Results: Exhaustive exercise significantly increased post-exercise fat oxidation, energy expenditure and contribution of fat to EE (p < 0.05). Also, it significantly decreased post-exercise carbohydrate (CHO) oxidation and the contribution of CHO to EE (p < 0.05). However, the changes in the substrate oxidation rate and EE after the exercise test were not different between the groups (p > 0.05). Conclusions: The study results suggest that a single short-duration exhaustive exercise session causes a higher fat oxidation rate during recovery than at rest, whereas training status did not affect this situation

Indirect calorimetry: methodological and interpretative problems

1990 ◽  
Vol 258 (3) ◽  
pp. E399-E412 ◽  
Author(s):  
D. C. Simonson ◽  
R. A. DeFronzo
Keyword(s):  
Indirect Calorimetry ◽  
Energy Production ◽  
Data Interpretation ◽  
Substrate Oxidation ◽  
Disappearance Rate ◽  
Direct Oxidation ◽  
Basic Principles ◽  
Major Route ◽  
Metabolic Pool

The technique of indirect calorimetry is now widely used to examine rates of energy production and substrate oxidation in humans. Although the basic principles of indirect calorimetry are well established, it is important to recognize that there are several potential pitfalls in the methodology and data interpretation that must be appreciated to properly understand and apply the results derived from this technique. In particular, one must recognize that the fundamental measurement provided by indirect calorimetry is the net disappearance rate of a substrate regardless of the metabolic interconversions that the substrate may undergo before its disappearance from its metabolic pool. Under most circumstances, direct oxidation represents the major route by which a substrate disappears from its metabolic pool, and the two terms are often used interchangeably. However, under conditions when rates of gluconeogenesis, ketogenesis, or lipogenesis are elevated, the presumed equivalence between oxidation and disappearance may no longer apply, even though the actual measurements derived from indirect calorimetry remain valid. When indirect calorimetry is combined with other in vivo metabolic techniques (e.g., the insulin clamp or radioisotope turnover methods) it can provide a powerful tool for noninvasively examining complex metabolic processes.

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