Early Physical Activity Adoption is Associated with 6 Month Engagement in a Weight Loss Intervention

Abstract

Physical activity has been identified as a key behavior contributing to weight loss and long-term weight maintenance. Current ACSM recommendations include engagement in 200-300 min/wk of moderate-to-vigorous physical activity (MVPA) for long-term weight maintenance. Strategies for achieving this high volume of activity warrant further investigation. PURPOSE: To examine the association between early MVPA adoption and 6-month MVPA engagement within a lifestyle intervention for weight loss. METHODS: 65 adults with Class I obesity (age: 46.2±7.6 years, BMI: 31.7±4.1 kg/m2) participated in a lifestyle intervention for weight loss. Groups were based on moderate (150 min/wk, N=29) and high (250 min/wk, N=36) MVPA prescriptions achieved by week 25. Diet was prescribed at 1200-1800 kcal/day in both groups. Physical activity was objectively measured at baseline and 6 months using a wearable activity monitor. The average minutes of MVPA were computed from self-reported diaries (weeks 2-5) to demonstrate adoption of activity within the first month of the intervention. Partial correlations controlling for baseline MVPA were used to determine the relationship between activity adoption (month 1) and MVPA engagement (month 6). RESULTS: There was a significant increase in MVPA in both the moderate (86.6±214.7 min/wk, p=.038) and high (226.7±208.7 min/wk, p<.001) prescription groups across the first 6-months of the intervention. Month 1 self-reported adoption of MVPA was associated with objectively measured MVPA engagement at month 6 in the high group (r=.44, p=.015), but not the moderate group. Likewise, month 1 self-reported adoption of MVPA was associated with 6-month change in body weight in the high group (r=.41, p=.016), but not the moderate group. CONCLUSIONS: When prescribing high-doses of MVPA within the context of a lifestyle intervention for weight loss, adopting activity in the first month appears to be important in achieving high activity thresholds at 6 months. However, this relationship was not apparent in lower doses of physical activity. Given the significance of relatively high doses of MVPA to improve weight loss success, it appears that it is important to target strategies for promoting early activity adoption. This may facilitate achievement of the ACSM recommended high-dose of physical activity. Supported by NIH (HL103646)