Greater Adherence to Recommended Morning Physical Activity is Associated With Greater Total Intervention-Related Physical Activity Changes in Bariatric Surgery Patients

Abstract

Background: This study examines whether performance of bout-related physical activity (PA) during morning hours is related to greater overall bout-related PA increases within a preoperative PA intervention for bariatric surgery (BS) patients.

Methods: Participants with severe obesity (n = 33; mean age = 45.6 ± 9.6 years; BMI = 45.7 ± 7.0 kg/m²) seeking BS were randomized to and completed 6 weeks of preoperative PA counseling (retention = 82.5%). Participants were encouraged to walk daily at a moderate intensity in bouts ≥ 10 minutes during morning hours to overcome time-related obstacles and establish a PA habit. Timing and amount of bout-related moderate-to-vigorous PA (MVPA) was assessed via objective monitor at pre- and postintervention.

Results: Greater proportion of bout-related MVPA performed during morning hours (4:00 AM-12:00 PM) at postintervention was associated with larger total increases in bout-related MVPA minutes/day (β = .40, P = .03). At postintervention, a greater proportion of participants whose longest MVPA bouts occurred during morning hours (n = 11) achieved the public health guideline (ie, ≥150 bout-related MVPA minutes/week) versus those whose longest MVPA bouts occurred during nonmorning hours (n = 19; 63.6% vs. 26.3%, P = .04).

Conclusions: Intervention-related increases in PA tended to be greatest when PA was performed in the morning. Morning exercise may be a viable strategy for promoting habitual PA in inactive BS patients.

Trial registration: ClinicalTrials.gov NCT00962325.

Keywords: accelerometer; behavioral intervention; exercise; obesity.

Figure 1

Flow of participants through the trail.

Figure 2

A. Mean proportion of daily bout-related moderate-to-vigorous physical activity (MVPA) minutes by hour of the day at post-intervention. B. Number and mean duration of MVPA bouts by hour of the day across the 7-day monitoring period at postintervention.

Figure 3

Differences between morning and non-morning exercisers in bout-related moderate-to-vigorous physical activity performed during morning hours, nonmorning hours, and all hours at postintervention. *P < .05. **P < .001 for morning exercisers vs. nonmorning exercisers.