Stroke Volume at Rest and During Exercise in Healthy Volunteers

Background Changes in cardiac output, driven by increased heart rate and stroke volume, are crucial for oxygen delivery during acute exercise and influence maximal oxygen uptake (VO₂max). Thoracic electrical bioimpedance provides a non-invasive alternative to traditional invasive methods by estimating stroke volume through impedance changes during ventricular filling and emptying. However, its test-retest reliability remains uncertain, requiring further investigation for use in acute and long-term training assessments.

Methods Inclusion: 12 healthy individuals (six males, six females) Exclusion: Known ischaemic heart disease, known heart failure, symptoms of disease within 2 weeks prior to the study, known malignant disease, claudication, pregnancy, unstable cardiac arrhythmic disease, renal or liver dysfunction, known chronic lung disease Design: Test-retest study of thoracic electrical bioimpedance-based stroke volume

Intervention: Acute exercise bout on a bicycle ergometer Statistical design: Rest-to-exercise changes, as well as between-day smallest real difference, coefficient of variation and intraclass correlation coefficient Sample size: Since this is a pilot study, the sample size is set at 12 in accordance with current recommendations.

Perspective The results are relevant for designing future studies in which stroke volume is measured and compared in response to various interventions at rest and during exercise.

Study Overview

• Status: Completed
• Conditions: Healthy
• Intervention / Treatment: Other: Cardiopulmonary exercise test

• Study Type: Interventional
• Enrollment (Actual): 12
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Denmark
  • Copenhagen, Denmark, 2100
    • Trygfondens Center for Aktiv Sundhed

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion criteria

• Men and women
• 18-70 years

Exclusion criteria

• Known chronic lung disease
• Known ischaemic heart disease
• Known heart failure
• Symptoms of disease within 2 weeks prior to the study
• Known malignant disease
• Claudication
• Pregnancy
• Unstable cardiac arrhythmic disease
• Renal or liver dysfunction

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Exercise bout; A cardiopulmonary exercise test (CPET), during which stroke volume and heart rate are continuously measured	Other: Cardiopulmonary exercise test; The two study days are identical, and consist of stroke volume, heart rate and non-invasive blood pressure measurements during upright rest, in the supine position, and during incremental exercise (CPET).

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Between-day smallest real difference (SRD) for stroke volume during upright rest	2-10 days
Between-day coefficient of variance (CV) for for stroke volume during upright rest	2-10 days

Secondary Outcome Measures

Outcome Measure	Time Frame
Between-day smallest real difference (SRD) for stroke volume during supine rest	2-10 days
Between-day coefficient of variance (CV) for stroke volume during supine rest	2-10 days
Between-day SRD for stroke volume at 60% of maximal workload (Wmax) during CPET	2-10 days
Between-day CV for stroke volume at 60% of Wmax during CPET	2-10 days

Other Outcome Measures

Outcome Measure	Time Frame
Between-day SRD for stroke volume at 40% of Wmax during CPET	2-10 days
Between-day CV for stroke volume at 40% of Wmax during CPET	2-10 days
Between-day SRD for stroke volume at 80% of Wmax during CPET	2-10 days
Between-day CV for stroke volume at 80% of Wmax during CPET	2-10 days
Between-day SRD for stroke volume at Wmax during CPET	2-10 days
Between-day CV for stroke volume at Wmax during CPET	2-10 days
Between-day intraclass correlation coefficient (ICC) for stroke volume during upright rest	2-10 days
Between-day ICC for stroke volume during supine rest	2-10 days
Between-day ICC for stroke volume at 60% of Wmax during CPET	2-10 days
Between-day ICC for stroke volume at 40% of Wmax during CPET	2-10 days
Between-day ICC for stroke volume at 80% of Wmax during CPET	2-10 days
Between-day ICC for stroke volume at Wmax during CPET	2-10 days
Between-day SRD for cardiac output (measured as the product of stroke volume and heart rate) during upright rest	2-10 days
Between-day CV for for cardiac output during upright rest	2-10 days
Between-day ICC for for cardiac output during upright rest	2-10 days
Between-day SRD for cardiac output during supine rest	2-10 days
Between-day CV for for cardiac output during supine rest	2-10 days
Between-day ICC for for cardiac output during supine rest	2-10 days
Between-day SRD for cardiac output at 60% of Wmax during CPET	2-10 days
Between-day CV for cardiac output at 60% of Wmax during CPET	2-10 days
Between-day ICC for cardiac output at 60% of Wmax during CPET	2-10 days
Between-day SRD for cardiac output at 40% of Wmax during CPET	2-10 days
Between-day CV for cardiac output at 40% of Wmax during CPET	2-10 days
Between-day ICC for cardiac output at 40% of Wmax during CPET	2-10 days
Between-day SRD for cardiac output at 80% of Wmax during CPET	2-10 days
Between-day CV for cardiac output at 80% of Wmax during CPET	2-10 days
Between-day ICC for cardiac output at 80% of Wmax during CPET	2-10 days
Between-day SRD for cardiac output at Wmax during CPET	2-10 days
Between-day CV for cardiac output at Wmax during CPET	2-10 days
Between-day ICC for cardiac output at Wmax during CPET	2-10 days
Between-day SRD for heart rate (measured with the CPET equipment) during upright rest	2-10 days
Between-day CV for for heart rate during upright rest	2-10 days
Between-day ICC for for heart rate during upright rest	2-10 days
Between-day SRD for heart rate during supine rest	2-10 days
Between-day CV for for heart rate during supine rest	2-10 days
Between-day ICC for for heart rate during supine rest	2-10 days
Between-day SRD for heart rate at 60% of Wmax during CPET	2-10 days
Between-day CV for heart rate at 60% of Wmax during CPET	2-10 days
Between-day ICC for heart rate at 60% of Wmax during CPET	2-10 days
Between-day SRD for heart rate at 40% of Wmax during CPET	2-10 days
Between-day CV for heart rate at 40% of Wmax during CPET	2-10 days
Between-day ICC for heart rate at 40% of Wmax during CPET	2-10 days
Between-day SRD for heart rate at 80% of Wmax during CPET	2-10 days
Between-day CV for heart rate at 80% of Wmax during CPET	2-10 days
Between-day ICC for heart rate at 80% of Wmax during CPET	2-10 days
Between-day SRD for heart rate at Wmax during CPET	2-10 days
Between-day CV for heart rate at Wmax during CPET	2-10 days
Between-day ICC for heart rate at Wmax during CPET	2-10 days
Uright-to supine changes in stroke volume, heart-rate and cardiac output and arterial blood pressure at rest	2-10 days
Changes in stroke volume from upright rest to exercise at 40%, 60%, 80% and 100% of Wmax.	2-10 days
Changes in cardiac output from upright rest to exercise at 40%, 60%, 80% and 100% of Wmax.	2-10 days
Changes in arterial blood pressure from upright rest to exercise at 40%, 60%, 80% and 100% of Wmax.	2-10 days

Collaborators and Investigators

• Sponsor: Rigshospitalet, Denmark

Study record dates

Study Major Dates

• Study Start (Actual): September 1, 2025
• Primary Completion (Actual): December 1, 2025
• Study Completion (Actual): December 1, 2025

Study Registration Dates

• First Submitted: August 31, 2025
• First Submitted That Met QC Criteria: January 5, 2026
• First Posted (Actual): January 6, 2026

Study Record Updates

• Last Update Posted (Actual): January 6, 2026
• Last Update Submitted That Met QC Criteria: January 5, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Keywords: Acute exercise; stroke volume; test-retest
• Additional Relevant MeSH Terms: Investigative Techniques; Diagnostic Techniques and Procedures; Diagnosis; Diagnostic Techniques, Respiratory System; Diagnostic Techniques, Cardiovascular; Heart Function Tests; Respiratory Function Tests; Ergometry; Exercise Test
• Other Study ID Numbers: H-25024676

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No