Dose-response relationship between accelerometer-measured physical activity and depression: evidence from the UK...

Area of Science:

• Epidemiology
• Public Health
• Exercise Science

Background:

• Most studies on physical activity (PA) and depression use self-reports, focusing on moderate-to-vigorous PA (MVPA).
• Limited research exists on accelerometer-measured PA, especially light physical activity (LPA), and depression risk in the general population.

Purpose of the Study:

• To investigate the dose-response relationship between accelerometer-measured PA and depression risk.
• To examine the impact of different PA intensities (LPA, MPA, VPA) and total PA volume on depression.
• To explore if PA's effect on depression differs in high-risk groups like women and individuals with obesity.

Main Methods:

• Prospective cohort study of 90,585 participants from the UK Biobank with accelerometer data.
• Assessed total PA volume (average overall acceleration) and weekly minutes of LPA, MPA, and VPA.
• Used Cox proportional hazards models with restricted cubic splines to analyze depression incidence over an average 8.35-year follow-up.

Main Results:

• Depression risk decreased with increasing total PA volume and time spent in LPA, MPA, and VPA up to certain thresholds (30 mg ACC, 2000 min LPA, 500 min MPA, 50 min VPA per week).
• Higher intensity PA (VPA) did not offer additional depression risk reduction compared to lower intensities when total PA volume was similar.
• LPA's protective effect was not significant in women and individuals with obesity, unlike in the general population.

Conclusions:

• Accelerometer-measured PA across all intensities is linked to reduced depression risk, primarily driven by volume rather than intensity.
• A threshold effect exists, beyond which increased PA yields diminishing returns for depression risk reduction.
• While overall PA is beneficial, MVPA remains the recommended intensity for women and individuals with obesity to mitigate depression risk.