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This is an interventional study that will examine how sedentary behavior (decreased physical inactivity) over time affects cardiovascular health (i.e. heart rate and blood pressure) and sleep quality/duration.
PRIMARY OBJECTIVES:
1. To test the hypothesis that two weeks of sedentary behavior will progressively impair vascular endothelial function.
2: To test the hypothesis that increasing sedentary behavior will decrease total sleep duration and sleep efficiency.
3: To test the hypothesis that two-weeks of sedentary behavior will progressively increase 24-h blood pressure and reduce nocturnal blood pressure dipping.
OUTLINE:
After a baseline period, participants will become more inactive and also come in for 4-h uninterrupted sitting visits. Cardiovascular, activity, and sleep measures will be taken throughout.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Sedentary to Active | Other | Participants will visit the research laboratory for baseline measurements at visit 1 after wearing a pedometer for one week and maintaining their typical level of physical activity. After the baseline visit, participants will reduce their step count by more than half for two weeks. Participants will visit the laboratory once every week during the 2 week interventional period for a total of 3 visits. |
|
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Reduced Activity | Behavioral | Participants reduce their activity level to <5,000 steps/day and <50 % of baseline steps. |
|
| Measure | Description | Time Frame |
|---|---|---|
| Endothelial Function | Investigators will measure endothelial function as flow-mediated dilation at baseline, and each hour of the 3-hour sitting trials. | 3 weeks |
| Oxidative stress | Oxidative stress will be measured using malondialdehyde adducts (MDA) from Ethylenediaminetetraacetic acid (EDTA) plasma. | 3 weeks |
| Endothelin-1 | Endothelin 1 (ET-1) will be measured from Ethylenediaminetetraacetic acid (EDTA) plasma. | 3 weeks |
| Heart rate | During the weekly trials, heart rate will be measured as beats per minute while participants are in a seated position during the prolonged sitting period. | 3 weeks |
| Blood pressure | During the weekly trials, blood pressure will be measured as systolic over diastolic in a seated position in the dominant arm | 3 weeks |
| 24-hour BP measurement | Investigators will measure 24-hour ambulatory blood pressure monitoring (AMBP, Spacelabs, Inc) at baseline and for 24-h before each in-lab visit. | 3 weeks |
| Sleep duration | Sleep duration will be scored from the ActiGraph and correlated with the sleep and activity diary. | 3 weeks |
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Inclusion Criteria:
Exclusion Criteria:
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| Name | Affiliation | Role |
|---|---|---|
| Saurabh Thosar, Dr. | Oregon Institute of Occupational Health Sciences | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Oregon Institute of Occupational Health Sciences | Recruiting | Portland | Oregon | 97239 | United States |
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| ID | Term |
|---|---|
| D057185 | Sedentary Behavior |
| D009043 | Motor Activity |
| ID | Term |
|---|---|
| D001519 | Behavior |
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| Sleep efficiency |
Sleep efficiency will be scored from the ActiGraph and correlated with the sleep and activity diary. |
| 3 weeks |
| Activity | Activity will be scored from the ActiGraph and correlated with the sleep and activity diary. | 3 weeks |
| Activity Perception | Activity perception will be measured before each prolonged sitting trial using an Activity Perception questionnaire (Perception of Current Activity Questionnaire). The questionnaire has 7 questions with answers ranging from 1 to 5. The range of scores is from 7 to 35, with 7 suggesting a strong negative perception of current activity, and 35 suggesting a strong positive perception of current activity. | 3 weeks |