The physical activity paradox revisited: a prospective study on compositional accelerometer data and long-term...

Area of Science:

• Occupational Health
• Epidemiology
• Physical Activity Research

Background:

• The physical activity paradox suggests leisure physical activity (PA) benefits health, whereas high occupational PA may harm it.
• Previous studies had limitations like self-reported PA, insufficient socioeconomic confounding adjustment, and not addressing PA composition.
• This study re-examines the PA paradox concerning long-term sick absence (LTSA) with improved methodology.

Purpose of the Study:

• To investigate the association between physical activity at work and in leisure with long-term sick absence (LTSA).
• To determine if the physical activity paradox persists after addressing methodological limitations of prior research.

Main Methods:

• 929 workers' physical behaviors (moderate-to-vigorous PA, sedentary time, etc.) were measured using accelerometry.
• Data was expressed as isometric log-ratios (ilrs) to account for the compositional nature of physical behaviors.
• Long-term sick absence (LTSA) was defined as ≥6 consecutive weeks of sickness absence over a 4-year follow-up, analyzed via Cox proportional hazards models.

Main Results:

• During follow-up, 21% of workers experienced LTSA.
• Increased leisure-time moderate-to-vigorous physical activity (MVPA) was associated with a 20% lower risk of LTSA (p=0.02).
• Increased occupational MVPA was associated with a 15% higher risk of LTSA (p=0.02), with results consistent after further adjustments.

Conclusions:

• The findings support the existence of the physical activity paradox.
• Leisurely physical activity appears protective against long-term sick absence, while occupational physical activity may increase absence risk.