Metabolic Thresholds and Fat Utilization Points Correlation

Study Overview
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Brief Summary
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To examine existence of connection between fat utilization points, both maximal and minimal with individual metabolic thresholds in different subjects. As a consequence, this innovative approach could offer a supplementary method for both aerobic and anaerobic thresholds detection as well as useful and practical exercise intensity selection marker.

Detailed Description
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This study aims to examine the existence of connection between metabolic thresholds and fat oxidation points in diverse group of subjects. From the physiological perspective, during exercise with increasing intensity, three phases of the body's energy utilization and two threshold points can be defined. These threshold points have been named metabolic thresholds and as such are considered as indicators of exercise capacities. Several authors have suggested, that the first threshold should be called the 'aerobic threshold' (AeT) and the second the 'anaerobic threshold' (AnT). The energy contribution from fat oxidation increases during low-to-moderate exercise intensities and then markedly declines when the intensity becomes high, at which point carbohydrates (CHO) remain the dominant energy substrate. A term used to describe exercise intensity where fat oxidation reaches optimum, is maximal fat oxidation point (FATmax) whereas exercise intensity matching the negligible fat oxidation is labelled FATmin. During physical activity, due to limited availability of CHO, subjects are more dependent on energy originating from fat when aiming to optimize endurance performance, body composition, optimize weight control and the metabolic rate. Exercise at the intensity eliciting FATmax revealed best results in treatment and prevention of obesity-associated conditions, cardio-vascular and pulmonary diseases by means of increase in maximal fat oxidation rates (MFO), insulin sensitivity, improvements in ventilator efficiency and cardiac output, demonstrating a significant role in the treatment of these impairments. As a follow-up, studies demonstrated how the lowest beneficial effect was observed when exercise was performed above intensity matching negligible fat oxidation rate (FATmin), contributing to diminished protection of exercise therapy. In consequence, increased cardio-metabolic demands of exercise performed above FATmin also have a higher impact on mortality rates in comparison to low-moderate aerobic exercise. Therefore, choosing appropriate exercise intensity may play a decisive role in decreasing risk factors accompanying obesity-associated conditions. Investigators aim to determine metabolic thresholds and fat oxidation points by using non-invasive breath-by-breath gas analysis during either treadmill or cycle ergometry. Metabolic thresholds will be detected by using gas analysis, via ventilatory parameters. Fat oxidation points will be determined using indirect calorimetry. Participants will perform graded ergometry test (2min stages and 1km/h or 50 W load increase), on either cycle or treadmill ergometer, till exhaustion to determine maximal oxygen uptake (VO2max), with gases being collected at the mouth level by using spiroergometry. The strength of the relationship between intensities matching VO2 at AeT and VO2 at FATmax will be assessed using the Pearson product moment (r) correlation coefficient with same being done for AnT and FATmin correlation. A coefficient of determination (R2) will be used to detect the proportion of existing variance. A paired t-test will be used to asses' differences between measured variables. Associated heart rate at the AeT/FATmax and AnT/FATmin will be used as training mean to identify proper training intensity. The time frame of the study is about 3 years, depending on the availability of the subjects. Planed study begin is early 2016. Participants will be every day clients of the Institution and will be recruited on a voluntary basis as they arrive to the testing facilities through this 3 years period.Through this 3 years period, statistical analysis of the collected data for each group of subjects will be performed and observations will be published. Up to 7 publications are expected to result from this research.

Official Title
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New Methodological Approach to Metabolic Thresholds Detection; Examining Fat Utilization Points and Metabolic Thresholds Correlation Strength

Conditions
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Exercise Physiology

Intervention / Treatment
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* Diagnostic Test: Metabolic thresholds and fat oxidation points relationship


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy Non smokers No evidence of any metabolic, pulmonary or cardiovascular diseases possibly affecting substrates utilization. No presence of musculoskeletal injuries (Must be able to perform graded exercise test on a treadmill or a cycle ergometer). Males and females, age 18-60, divided in following 4 groups: obese, sedentary, moderately trained, athletes. For obese group of individuals, body fat > 30% For sedentary group of individuals, no physical activity in last 3 years For athletic group of individuals, > 12 h training per week For moderately trained individuals. < 3 h per week of physical activity Willing to allow data publication. Exclusion Criteria: Evidence of any metabolic, pulmonary or cardiovascular diseases possibly affecting substrates utilization. Smokers. High blood pressure. Using supplements possibly affecting substrates utilization. Non willing to allow data publication. Not finishing grade exercise test protocol till exhaustion to determine VO2max.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Obese men and women<br>Metabolic thresholds and fat oxidation points relationship in Obese males and females, age 18-60y, body fat > 30% | Diagnostic Test: Metabolic thresholds and fat oxidation points relationship<br>* Investigators aim to determine exercise intensity at which metabolic thresholds and fat oxidation points occur by using non-invasive breath-by-breath gas analysis during either graded treadmill or cycle ergometry test (2min stages and 1km/h or 50 W load increase) till exhaustion to determine maximal oxygen uptake (VO2max), with gases being collected at the mouth level. The strength of the relationship between AeT and at FATmax will be assessed using the Pearson product moment (r) correlation coefficient with same being done for AnT and FATmin correlation. A coefficient of determination (R2) will be used to detect the proportion of existing variance. A paired t-test will be used to asses' differences between measured variables. Bland-altman will be used to determine levels of agreement.<br>|
| Male and female athletes<br>Metabolic thresholds and fat oxidation points relationship in Athletic males and females, age 18-60y. | Diagnostic Test: Metabolic thresholds and fat oxidation points relationship<br>* Investigators aim to determine exercise intensity at which metabolic thresholds and fat oxidation points occur by using non-invasive breath-by-breath gas analysis during either graded treadmill or cycle ergometry test (2min stages and 1km/h or 50 W load increase) till exhaustion to determine maximal oxygen uptake (VO2max), with gases being collected at the mouth level. The strength of the relationship between AeT and at FATmax will be assessed using the Pearson product moment (r) correlation coefficient with same being done for AnT and FATmin correlation. A coefficient of determination (R2) will be used to detect the proportion of existing variance. A paired t-test will be used to asses' differences between measured variables. Bland-altman will be used to determine levels of agreement.<br>|
| Sedentary females and males<br>Metabolic thresholds and fat oxidation points relationship in Sedentary females and males, age 18-60y, | Diagnostic Test: Metabolic thresholds and fat oxidation points relationship<br>* Investigators aim to determine exercise intensity at which metabolic thresholds and fat oxidation points occur by using non-invasive breath-by-breath gas analysis during either graded treadmill or cycle ergometry test (2min stages and 1km/h or 50 W load increase) till exhaustion to determine maximal oxygen uptake (VO2max), with gases being collected at the mouth level. The strength of the relationship between AeT and at FATmax will be assessed using the Pearson product moment (r) correlation coefficient with same being done for AnT and FATmin correlation. A coefficient of determination (R2) will be used to detect the proportion of existing variance. A paired t-test will be used to asses' differences between measured variables. Bland-altman will be used to determine levels of agreement.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Relationship between metabolic threshold and fat oxidation points (FATmax) matching %HRmax | Regular exercise at FATmax intensity has been proposed as a key factor to optimize the body's ability to oxidize lipids.Exercise intensity matching FATmax will be determined via indirect calorimetry and expressed by using %HRmax.In contrast to the %HRmax method, an individualized approach to exercise intensity prescription based on metabolic thresholds describes specific metabolic phases during exercise and intends to account for differences in the body's physiological and functional capacity.Metabolic thresholds will be determined via either gas analysis or/and lactate analysis and expressed in %HRmax.If connection between these two %HRmax exists,it would integrate the most relevant indices for planning and assessing an effective exercise program.Existence of connection between %HRmax matching both parameters will be evaluated by using correlation and levels of agreement by using MedCalc statistical software. | Each primary outcome measure (metabolic thresholds and fat oxidation points, is sampled continuously through the test. Test duration is 12-16 minutes.Existence of correlation will be evaluated immediately after test | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Relationship between metabolic threshold and fat oxidation points (FATmax) matching %VO2max | Regular exercise at FATmax intensity has been proposed as a key factor to optimize the body's ability to oxidize lipids.Exercise intensity matching FATmax will be determined via indirect calorimetry and expressed by using %VO2max.In contrast to the %VO2max method, an individualized approach to exercise intensity prescription based on metabolic thresholds describes specific metabolic phases during exercise and intends to account for differences in the body's physiological and functional capacity.Metabolic thresholds will be determined via either gas analysis or/and lactate analysis and expressed in %VO2max.If connection between these two %VO2max exists, it would integrate the most relevant indices for planning and assessing an effective exercise program.Existence of connection between %VO2max matching both parameters will be evaluated by using correlation and levels of agreement by using MedCalc statistical software. | Each primary outcome measure (metabolic thresholds and fat oxidation points, is sampled continuously through the test. Test duration is 12-16 minutes. Existence of correlation will be evaluated immediately after test | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Exercise, Metabolic thresholds, Fat oxidation