Clinical trial NCT06937164: Blood Pressure Following Isometric Exercise in Inactive Adults
Official title: Beliefs and Expectation Effects on Blood Pressure Following Isometric Exercise in Inactive Adults
Study type: INTERVENTIONAL
Overall status: RECRUITING
Phase: NA
Conditions: Hypertension
Elevated Blood Pressure
Sedentary Lifestlye
Keywords: Isometric Exercise
Blood Pressure
Post-Exercise Hypotension
Physical Inactivity
Heart Rate Variability
Electromyography (EMG)
Muscle Fatigue
Cardiovascular Adaptation
Exercise Intervention
Non-Pharmacological Treatment
Hypertension Prevention
Autonomic Nervous System
BELIEF-BP
Lead sponsor: Canterbury Christ Church University
Sponsor class: OTHER
First posted: 2025-04-22
Enrollment: 36
Sex: ALL
Minimum age (years): 18
Maximum age (years): 55
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Intervention model description: Participants are randomly assigned to one of three parallel groups: (1) isometric exercise training (IET) with neutral information, (2) IET with expectation-enhancing information, or (3) a no-intervention control group. Intervention groups complete repeated isometric leg extension sessions across multiple visits. Prior to training, participants receive distinct information to influence their beliefs about IET. The control group does not receive training or information. Participants are blinded to group assignment, and outcomes such as blood pressure, heart rate variability, and muscle fatigue are assessed independently across groups.
Primary purpose: BASIC_SCIENCE

Brief summary: This study investigates how isometric exercise training (IET) affects blood pressure in physically inactive adults. Isometric exercise involves sustained muscle contractions without movement-for example, pushing against a fixed object. Previous research has shown that IET may help reduce blood pressure, but the mechanisms involved are not fully understood.

The purpose of this study is to assess both the immediate (acute) and long-term (chronic) effects of IET on cardiovascular outcomes. Participants will complete a series of lab-based exercise sessions over several weeks. In these sessions, they will perform repeated bouts of isometric leg extensions while seated on an exercise machine designed to measure muscle force.

Throughout the study, researchers will monitor participants' blood pressure, heart rate, and muscle activity. Acute responses-such as post-exercise hypotension (a short-term drop in blood pressure)-will be measured immediately after exercise. Chronic changes, such as resting blood pressure improvements, will be evaluated across the training period.

Additional measurements will include heart rate variability (HRV), which gives insight into autonomic nervous system activity, and electromyography (EMG), which tracks muscle fatigue and activation patterns. These data will help explore potential mechanisms behind the cardiovascular benefits of IET.

By examining how repeated sessions of isometric exercise influence blood pressure and related physiological responses, this research may support the use of IET as a non-pharmacological strategy for managing or preventing hypertension in physically inactive individuals.


Eligibility criteria: Inclusion Criteria:

* Age 18 years or older
* Self-reported physically inactive or insufficiently active (not meeting current physical activity guidelines)
* Not currently engaged in structured resistance or isometric exercise training
* Able to attend lab sessions over a 4-week period
* Provides written informed consent

Exclusion Criteria:

* Current diagnosis of hypertension requiring medication
* Any known cardiovascular, neurological, or musculoskeletal condition contraindicating isometric exercise
* Formal education or professional background in exercise science, physiology, or a related field
* Pregnant or planning to become pregnant during the study period
* Inability to follow verbal instructions or complete study protocols

Primary outcomes:
measure: Change in Resting Systolic Blood Pressure
timeFrame: Baseline to Post-Intervention (approximately 4 weeks)
Secondary outcomes:
measure: Change in Diastolic Blood Pressure
timeFrame: Baseline to Post-Intervention (approximately 4 weeks)
measure: Post-Exercise Hypotension Response
timeFrame: During the first week of the exercise intervention. Sessions 1, 2 and 3.
measure: Change in Heart Rate Variability (HRV)
timeFrame: Baseline to Post-Intervention (approximately 4 weeks)
measure: Change in Muscle Fatigue Markers (EMG)
timeFrame: Baseline to Post-Intervention (Approximately 4 weeks)
Other outcomes:
Locations:
city: Canterbury
country: United Kingdom
facility: Canterbury Christ Church University
state: Kent
Study officials:
affiliation: Canterbury Christ Church University
name: Sean Machak
role: PRINCIPAL_INVESTIGATOR
References: