Fitness and Fat Oxidation in Overweight Chinese, Indian and Malay Men
Condition: Overweight and Obesity
MeSH terms: Overweight
Study type: Observational

Summary: 
      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: 
      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.
    

Intervention name(s): Cardiorespiratory fitness test; Resting measure of fat oxidation; Maximum fat oxidation test
Intervention type(s): Other; Other; Other
Intervention description(s): Progressive submaximal exercise test on a treadmill to predict cardiorespiratory fitness; Use of ventilated hood attached to automated metabolic cart to measure substrate oxidation at rest; Progressive exercise test to determine maximum fat oxidation during exercise
Other intervention name(s): Graded exercise test, submaximal oxygen uptake test; Resting energy expenditure, resting substrate oxidation test
Observational model: Case-Only
Time perspective: Cross-Sectional
Sampling method: Non-Probability Sample
Study population: 
        Healthy but physically inactive Chinese, Indian and Malay men aged 21-45 years with an
        elevated body mass index for Asians.