Reducing Sedentary Behavior to Improve Sleep: an Ancillary Study to the RESET BP Clinical Trial

Disturbed sleep, most notably insomnia and obstructive sleep apnea (OSA), is highly prevalent and associated with increased risk for elevated blood pressure (BP) and cardiovascular disease. Unfortunately, despite the substantial public health burden of disturbed sleep, standard treatments are often limited by poor adherence, inadequate availability, and/or significant side effects. As such, identification of alternative approaches to mitigate disturbed sleep is greatly needed. In contrast to increasing engagement in exercise, we propose that reducing sedentary behavior (SED), or time spent sitting, is a novel and feasible approach to reduce sleep disturbance. We also propose that the presence of disturbed sleep during the intervention could blunt the adherence to attempted SED reduction and impact its cardiovascular health benefits. Therefore, the goal of this ancillary study is to test the hypotheses that SED reduction will improve sleep and that the presence of baseline sleep disturbance will reduce the effectiveness of SED reduction efforts. We will test this hypothesis by adding comprehensive sleep assessments to an ongoing randomized clinical trial (NCT03307343) that is examining the effect of SED reduction on BP. In this parent trial, 300 desk workers with elevated BP are randomized to a 3-month multicomponent behavioral intervention aimed at replacing 2-4 hr/day of SED with light-intensity activity or a 3-month no-contact control condition.

Anticipating the ability to enroll 150 participants from the remaining sample of the parent trial (estimated N~210), we will assess sleep at baseline and post-intervention using 7 nights of wrist-worn actigraphy and 1 night of home-based polysomnography (PSG), yielding objective measures of sleep quality (WASO), total sleep time (TST), OSA severity (apnea-hypopnea index [AHI]), and sleep depth (slow-wave sleep [SWS]. These data will allow us to efficiently address the following specific aims:

Aim 1: To evaluate the effect of a 3-month SED reduction intervention on objective measures of sleep quality, depth, duration, and OSA severity.

Hypothesis: Participants randomized to the SED reduction intervention will have greater reduction than control participants in actigraphy-assessed WASO (primary outcome [hypothesis 1.1]), PSG-assessed AHI and SWS, and greater increase in actigraphy-assessed TST (secondary outcomes [hypothesis 1.2]).

Aim 2: To examine the effect of baseline disturbed sleep on SED reduction and BP improvement.

Hypothesis: Intervention-induced reductions in SED (hypothesis 2.1) and BP (hypothesis 2.2) will be smaller among individuals with disturbed sleep (e.g., elevated WASO or AHI) at baseline.

Inclusion criteria

• Age 21-65 years
• SBP of 120-159 mmHg or DBP of 80-99 mmHg
• Physically inactive or insufficiently active (i.e., not meeting current aerobic MVPA recommendations [≥150 min/wk])
• Currently perform deskwork for ≥ 20 hr/wk at a desk compatible with a sit-stand desk attachment
• Employment within 25-mi radius of University of Pittsburgh
• Stable employment (≥ 3 mo at current job, plan to be in current job for at least the next 3 mo)
• Supervisor approval to join intervention
• Possession of cellular phone able to receive text messages

Exclusion criteria

• SBP ≥ 160 mmHg or DBP ≥ 100 mmHg
• Use of anti-hypertensive or glucose-controlling medication
• Comorbid condition that would limit ability to reduce sedentary behavior (e.g., musculoskeletal condition)
• History of ischemic heart disease, chronic heart failure, stroke, or chronic kidney disease
• Inability to obtain consent from primary care provider/physician to participate
• Current use of a sit-stand desk or sedentary behavior prompting device
• Current enrollment in a weight loss or exercise program, recent (< 1 yr) or planned bariatric surgery
• Plans to be away from work for an extended period (>1 wk) during the study period
• Current or recent (within last 6 mo) pregnancy; current or recent (within last 3 mo) breastfeeding
• Undiagnosed severe OSA (AHI ≥ 30) or insomnia (ISI ≥ 22)