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.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
OTHER
Masking
NONE
Enrollment
20
Participants reduce their activity level to \<5,000 steps/day and \<50 % of baseline steps.
Oregon Institute of Occupational Health Sciences
Portland, Oregon, United States
RECRUITINGEndothelial Function
Investigators will measure endothelial function as flow-mediated dilation at baseline, and each hour of the 3-hour sitting trials.
Time frame: 3 weeks
Oxidative stress
Oxidative stress will be measured using malondialdehyde adducts (MDA) from Ethylenediaminetetraacetic acid (EDTA) plasma.
Time frame: 3 weeks
Endothelin-1
Endothelin 1 (ET-1) will be measured from Ethylenediaminetetraacetic acid (EDTA) plasma.
Time frame: 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.
Time frame: 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
Time frame: 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.
Time frame: 3 weeks
Sleep duration
Sleep duration will be scored from the ActiGraph and correlated with the sleep and activity diary.
Time frame: 3 weeks
Sleep efficiency
Sleep efficiency will be scored from the ActiGraph and correlated with the sleep and activity diary.
Time frame: 3 weeks
This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.
Activity
Activity will be scored from the ActiGraph and correlated with the sleep and activity diary.
Time frame: 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.
Time frame: 3 weeks