Physical activity under confinement and free-living conditions

Area of Science:

• Exercise Physiology
• Human Metabolism
• Behavioral Science

Background:

• Limited data exists on physical activity (PA) and energy expenditure (EE) in Asian populations under controlled versus free-living conditions.
• Understanding these relationships is crucial for accurate health assessments and behavioral research.

Purpose of the Study:

• To investigate the relationship between physical activity (PA) and energy expenditure (EE) in Asian individuals under confinement (respiratory chamber) and free-living conditions.
• To assess the validity of chamber-based PA measurements against free-living data.

Main Methods:

• Eighty-six Japanese adults (mean age 38±12 years) participated.
• 24-hour energy expenditure (EE) was measured in a respiratory chamber, including assigned moderate walking exercises.
• Free-living PA was assessed for 7 days using a validated accelerometer.

Main Results:

• PA levels in the chamber (1.47±0.11 multiples of basal EE) were lower than free-living (1.53±0.12), but closely correlated (r=0.744, p<0.001).
• Residual analysis revealed systematic errors, with a widening gap at higher free-living PA levels.
• Daily step counts showed no correlation between the two conditions.

Conclusions:

• Chamber-based PA measurements are compatible with free-living PA at a group level for Asian adults.
• Discrepancies in daily step counts highlight limitations in direct comparison between controlled and free-living environments.
• Chamber-based PA assessments may offer valuable insights for behavioral research on daily human activity.