Fitness and Fat Oxidation in Overweight Chinese, Indian and Malay Men

Study Overview
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Brief Summary
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South Asian men have lower cardiorespiratory fitness (CRF) than white men which is associated with a reduced capacity to oxidise fat during exercise. This is a risk factor for weight gain/regain. Whilst comparisons with Europeans are valuable, Asians are not a homogenous group and substantial differences in obesity and body fat partitioning exist with ethnicity. This cross-sectional pilot investigation aims to compare CRF and fat oxidation at rest and during exercise in Chinese, Indian and Malay men (from Singapore) with elevated BMI (23 -30 kg/m2). Forty-five men (15 each ethnicity) with elevated body mass index (23 -30 kg/m2) will complete testing in a fasted state on two separate mornings separated by ≥72 hours: (i) for a measure of CRF; and (ii) for a measure of fat oxidation at rest and during incremental exercise.

Detailed Description
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South Asian men have lower cardiorespiratory fitness (CRF) than white men which is associated with a reduced capacity to oxidise fat during exercise. This is a risk factor for weight gain/regain. Whilst comparisons with Europeans are valuable, Asians are not a homogenous group and substantial differences in obesity and body fat partitioning exist with ethnicity. This cross-sectional pilot investigation aims to compare CRF and fat oxidation at rest and during exercise in Chinese, Indian and Malay men (from Singapore) with elevated BMI (23 -30 kg/m2). Forty-five men (15 each ethnicity) with elevated body mass index (23 -30 kg/m2) will complete testing in a fasted state on two separate mornings separated by ≥72 hours: (i) for a measure of CRF; and (ii) for a measure of fat oxidation at rest and during incremental exercise. A submaximal exercise test will be used to estimate CRF (maximum oxygen uptake, VO2max) during walking using a standard protocol where subjects walk on a treadmill at 5 km/h with regular increments in gradient until individuals reach 80% of their estimated maximum heart rate [220 - age (years)]. Perceived exertion will be monitored assessed periodically during the test and expired gases continuously measured via a mouthpiece attached to an automated metabolic cart (Parvomedics MMS-2400; Parvomedics, Sandy, UT). Oxygen consumption will be extrapolated to estimate VO2max based on estimated maximum heart rate. Resting fat oxidation will be determined via a 30 minute measure of expired gases under a ventilated hood attached to an automated metabolic cart. Fat oxidation during exercise will be determined via walking on a treadmill with increments in speed and gradient until the respiratory exchange ratio is ≥ 0.95. Primary outcomes will be compared among groups and adjusted for any covariates (e.g., BMI, body fat percentage) as necessary.

Official Title
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Differences in Cardiorespiratory Fitness and Fat Oxidation at Rest and During Exercise in Chinese, Indian and Malay Men With Elevated Body Mass Index.

Conditions
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Overweight and Obesity

Intervention / Treatment
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* Other: Cardiorespiratory fitness test
* Other: Resting measure of fat oxidation
* Other: Maximum fat oxidation test


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: male age 25 - <45 years Chinese, Indian or Malay based on self-identity for three generations (parents and grandparents) BMI ≥ 23 - < 30 kg/m2 and/or waist circumference ≥ 90 cm physically inactive defined as < 150 minutes moderate or < 75 minutes vigorous leisure-time physical activity per week, or the equivalent combination of both Exclusion Criteria: females personal history of cardio-metabolic diseases dieting (i.e. restricting food/energy intake) smokers consuming alcohol > 3 times per week with > 3 drinks per time using any medications which affect carbohydrate or lipid metabolism any lower body injuries fasting blood glucose > 6.1 mmol/L

Ages Eligible for Study
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Minimum Age: 21 Years
Maximum Age: 45 Years

Sexes Eligible for Study
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Male

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 |
| --- | --- |
| Chinese men<br>Chinese men based on self-identity for three generations (parents and grandparents), age 25 - <45 years, who are physically inactive (< 150 minutes moderate or < 75 minutes vigorous leisure-time physical activity per week), with elevated body mass index (>23-<30 kg/m2) for Asians. Single measure of CRF, resting fat oxidation and fat oxidation during graded exercise. | Other: Cardiorespiratory fitness test<br>* Progressive submaximal exercise test on a treadmill to predict cardiorespiratory fitness<br>* Other names: Graded exercise test, submaximal oxygen uptake test;Other: Resting measure of fat oxidation<br>* Use of ventilated hood attached to automated metabolic cart to measure substrate oxidation at rest<br>* Other names: Resting energy expenditure, resting substrate oxidation test;Other: Maximum fat oxidation test<br>* Progressive exercise test to determine maximum fat oxidation during exercise<br>|
| Indian men<br>Indian men based on self-identity for three generations (parents and grandparents), age 25 - <45 years, who are physically inactive (< 150 minutes moderate or < 75 minutes vigorous leisure-time physical activity per week), with elevated body mass index (>23-<30 kg/m2) for Asians. Single measure of CRF, resting fat oxidation and fat oxidation during graded exercise. | Other: Cardiorespiratory fitness test<br>* Progressive submaximal exercise test on a treadmill to predict cardiorespiratory fitness<br>* Other names: Graded exercise test, submaximal oxygen uptake test;Other: Resting measure of fat oxidation<br>* Use of ventilated hood attached to automated metabolic cart to measure substrate oxidation at rest<br>* Other names: Resting energy expenditure, resting substrate oxidation test;Other: Maximum fat oxidation test<br>* Progressive exercise test to determine maximum fat oxidation during exercise<br>|
| Malay men<br>Malay men based on self-identity for three generations (parents and grandparents), age 25 - <45 years, who are physically inactive (< 150 minutes moderate or < 75 minutes vigorous leisure-time physical activity per week), with elevated body mass index (>23-<30 kg/m2) for Asians. Single measure of CRF, resting fat oxidation and fat oxidation during graded exercise. | Other: Cardiorespiratory fitness test<br>* Progressive submaximal exercise test on a treadmill to predict cardiorespiratory fitness<br>* Other names: Graded exercise test, submaximal oxygen uptake test;Other: Resting measure of fat oxidation<br>* Use of ventilated hood attached to automated metabolic cart to measure substrate oxidation at rest<br>* Other names: Resting energy expenditure, resting substrate oxidation test;Other: Maximum fat oxidation test<br>* Progressive exercise test to determine maximum fat oxidation during exercise<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Cardiorespiratory fitness | Predicted measure of maximum oxygen uptake during exercise | 1 day (Single measurement) | 
| Resting fat oxidation | Measure of amount of fat oxidised whilst at rest in the postabsorptive (fasting) state | 1 day (Single measurement) | 
| Maximum fat oxidation (exercise) | Measure of maximum amount of fat oxidised whilst exercising in the postabsorptive state | 1 day (Single measurement) |