Physical activity has a weight-independent effect on mortality

1. Higher device-measured physical activity was associated with a lower risk of mortality irrespective of body mass index (BMI).

2. Compared with obese participants, there were no survival benefits of having a normal weight if physical activity remained low.

Evidence Rating Level: 1 (Excellent)

Maintaining a healthy body weight is important to prevent chronic disease. However, the dose-response association between body mass index (BMI) and the risk of premature mortality is debated. Exercise plays an important role in this relationship however current studies are based off self-reported data which are prone to biases. As a result, the primary goal of the present meta-analysis sought to examine the combined association of device-measured total and intensity-specific physical activity and sedentary time with BMI in relation to the risk of all-cause mortality.

From 8 prospective cohorts identified between database inception to July 2018, 34 492 participants (72% women) were included. Participants were included if they were >40 years and recorded at least 10 hours of accelerometer wear time per day for 4 or more days. Exclusion criteria included: <2 years follow-up, BMI <18.5 kg/m² or who have a history of cardiovascular disease (CVD) or cancer. 9 physical activity-BMI combinations were created for each physical activity intensity exposure.

Results demonstrated that higher device-measured physical activity was associated with a lower risk of mortality irrespective of BMI. Furthermore, compared with obese participants, there were no survival benefits of having a normal weight if physical activity remained low. However, this study was limited as it did not consider changes in physical activity or BMI over time. Nonetheless, the results from this study suggest that physical activity plays an important role in decreasing mortality risk irrespective of weight.

Click to read the study in British Journal of Sports Medicine

Image: PD

©2022 2 Minute Medicine, Inc. All rights reserved. No works may be reproduced without expressed written consent from 2 Minute Medicine, Inc. Inquire about licensing here. No article should be construed as medical advice and is not intended as such by the authors or by 2 Minute Medicine, Inc.