Informing Workplace Sedentary Behavior Interventions Through Momentary Affective States And Email-based Prompts.

Abstract

PURPOSE: The study aimed to (a) examine the effect of momentary affective states on workplace sedentary behavior (WSB); and (b) test the proximal effects of email-based prompts on WSB. METHODS: Office workers with sit-stand desks were recruited in a two-part 20-workday study. In part A, participants completed ecological momentary assessments (EMA; at 3 random times/day) of affective states. Each EMA response was matched with behavioral outcomes (i.e., time spent sedentary, standing, or moving proceeding each EMA response). Part B involved a micro-randomized prompt-based trial. Prompt delivery was randomized to be sent (ST) or not sent (NST) to all participants (probability of 0.5), at eight decision points per day between 9am and 5pm. Half of the prompts encouraged standing and the other half encouraged moving. An activPAL device was used continuously through the 20 days to measure WSB. Multilevel models were used to examine the associations of workplace behaviors and affective states. General estimating equations were used to examine the likelihood of a response to a prompt (i.e., transition from sitting to standing/moving) over the proceeding 5 and 30 min intervals. All models were adjusted for age, gender, race, and job type. RESULTS: Participants (N = 18; 56% females) who completed part A contributed 493 EMA responses (27.4±13.3 EMA responses/participant). When examining momentary relationships, individuals sat less (b[SE]= -3.9[1.8], p=.02) and stood more (b[SE]= 3.5[1.6], p=.02) in the hour following higher than usual energy and sat less (b[SE]= -2.8[1.4], p=.04) and moved more (b[SE]= 1.2[0.4], p<.01) following higher than usual intentions to stand/ move. Among participants (N = 15; 67% female; age = 50.9 ± 9.5yrs) who completed part B, 1147 decision points occurred when seated. Participants were 42% more likely to transition from sitting to standing within 5 mins when a prompt was sent (OR[95%CI] = 1.4[1.1, 1.8], p<.01). Stand prompts were 25% more likely to elicit a transition (OR[95%CI] = 1.6[1.2, 2.0], p<.01) than move prompts (OR[95%CI] = 1.3[1.0, 1.7], p<.05). CONCLUSIONS: Prompts may be an effective complementary strategy to encourage sit-stand desks use. Information regarding context (i.e., affective states and intentions) may complement these findings in developing just-in-time interventions.