Clinical trial NCT04207333: Combined Effects of Prolonged Sitting and Mental Stress on the Cardiovascular System
Official title: The Combined Effects of Prolonged Sitting and Mental Stress on Vascular and Cerebrovascular Function in Middle-Aged Adults
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Sedentary Behavior
Cardiovascular Risk Factor
Mental Stress
Cognitive Change
Cerebrovascular Insufficiency
Lead sponsor: University of North Carolina, Chapel Hill
Sponsor class: OTHER
Collaborators: name: North Carolina Translational and Clinical Sciences Institute
First posted: 2019-12-20
Enrollment: 6
Sex: ALL
Minimum age (years): 35
Maximum age (years): 59
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Intervention model description: Participants will be exposed to mental stress following either 20 min or 120 min sitting
Primary purpose: PREVENTION

Brief summary: Prolonged sitting may pose a public health risk through its effects on the cardiovascular system, and may lead to impaired whole-body cardiovascular health, which includes both vascular and cerebrovascular function. These effects may interact with other environmental variables, such as stress. However, no study has investigated the combined effect of a mental stressor and prolonged sitting on vascular and cerebrovascular function. The combined effect of prolonged sitting and mental stress may lead to an exacerbated effect on vascular, cerebrovascular, and executive function. The investigators hypothesize that mental stress with the addition of prolonged sitting \[PS\] will result in a greater increase in peripheral, central and cerebral arterial stiffness and elicit a decrease in cerebral perfusion, total blood flow to the brain, middle cerebral artery velocity and executive function, compared to mental stress without prolonged sitting \[CON\]. The findings from this study may result in a public health message regarding sedentary behavior and stress, and will help elucidate the mechanisms behind acute vascular, cerebrovascular, and cognitive dysfunction during prolonged sitting.

Detailed description: This study is a multi-visit (three in total) randomized crossover trial. During a single familiarization session, the research team will obtain informed consent, and will describe to participants the purposes and procedures of this study. They will then be exposed to all experimental devices on in a quiet, dimly lit and environmentally controlled room. Participants will return to the same location for two experimental conditions following these pre-assessment guidelines:

* Fasted (\> 12 hours), consuming only water.
* No caffeine consumption 12 hours prior to testing.
* No vigorous exercise 24 hours prior to testing.
* No alcohol consumption 24 hours prior to testing.

Participants will arrive to the Applied Physiology Laboratory between 6:00 and 10:00 a.m. fasted (for Visit 3: 2-5 days following the Visit 2). Participants will be fasted and refrain from caffeine intake for at least 12 hours, and alcohol and strenuous physical activity for at least 24 hours prior to arrival. Upon arrival, height and weight will be recorded followed by 10 minutes of quiet rest in the supine position. During these 10 minutes, the subject will be fitted with a Near Infra-Red Spectroscopy probe on the prefrontal cortex and medial gastrocnemius. The non-invasive continuous blood pressure, transcranial doppler, and Vicorder arterial stiffness devices will also be affixed to the participant during this time period during this time. Sitting periods will begin for both conditions once all devices are attached to the participant, the subject is shifted to an upright seated position, and at least 10 minutes of supine rest has been recorded. During the control (CON) visit, subjects will undergo a brief 20 minute sitting period. For the prolonged sitting (PS) condition, subjects will be asked to sit still and quietly for 2 hours while watching a non-stimulating documentary. Each condition will receive the mental stress at the conclusion of the sitting periods in both CON and PS. After exposure to the mental stress in both conditions, data collection procedures for this protocol will be completed. Arterial stiffness measurements will be made immediately after the mental stress, and then every 5 minutes, up to 30 minutes. Brain blood flow will be assessed by ultrasound after completion of the arterial stiffness measures. Finally, a battery of cognitive tests (Verbal Fluency Test and Trails A+B tests) will be administered to the participant.

Eligibility criteria: Inclusion Criteria:

* Healthy male or female

Exclusion Criteria:

* Any known cardio-metabolic disorders
* Taking medications known to affect cardiovascular function
* Report drug or alcohol abuse
* Report cigarette smoking
* Pregnant women

Primary outcomes:
measure: Mean Change in Brachial-femoral Pulse Wave Velocity (bfPWV)
timeFrame: Baseline and immediately following the acute mental stressor
measure: Change in Heart-middle Cerebral Artery Pulse Wave Velocity (Brain PWV)
timeFrame: Baseline and immediately following the acute mental stressor
Secondary outcomes:
measure: Mean Change Carotid-femoral Pulse Wave Velocity (PWV)
timeFrame: Baseline and immediately following the acute mental stressor
measure: Mean Change in Femoral-ankle PWV
timeFrame: Baseline and immediately following the acute mental stressor
measure: Mean Change Augmentation Index
timeFrame: Baseline and immediately following the acute mental stressor
measure: Mean Executive Function
timeFrame: following the acute mental stressor
measure: Neurovascular Coupling
timeFrame: following the acute mental stressor
Other outcomes:
Locations:
city: Chapel Hill
country: United States
facility: University of North Carolina at Chapel Hill
state: North Carolina
Study officials:
affiliation: University of North Carolina, Chapel Hill
name: Jade Blackwell, MS
role: PRINCIPAL_INVESTIGATOR
affiliation: University of North Carolina, Chapel Hill
name: Lee Stoner, PhD, MPH
role: STUDY_DIRECTOR
References: