Effect of Low-intensity Aerobic Regular Activity on Heart Rate Variability in Type 1 Diabetes (ELARA-T1D)

April 13, 2026 updated by: University of Banja Luka
A monocentric prospective randomized trial included 35 patients with Type 1 diabetes. Participants were randomized into two groups: Group A with the patients who engaged in low-intensity physical activity matching aerobic threshold five days per week over a one-year observation period and Group B with the patients who engaged in physical activity less than five days per week. The study included three clinical visits: at baseline, at six months, and at one year. Assessments included cardiopulmonary exercise testing (CPET) and body composition analysis during the baseline visit and at six-month visit, while 24-hour Holter monitoring was conducted at baseline and at the final visit. Biochemical parameters and microvascular complication risk assessments were performed at every visit.

Study Overview

Status

Active, not recruiting

Conditions

Intervention / Treatment

Detailed Description

The ELARA-T1D study aims to investigate the impact of regular, long-standing low-intensity aerobic physical activity on heart rate variability (HRV) and cardiovascular autonomic neuropathy (CAN) in patients with Type 1 Diabetes Mellitus (T1DM). While physical activity is a cornerstone of diabetes management, fear of hypoglycemia and lack of specific guidelines often prevent patients from engaging in exercise. The mechanisms by which physical activity improves cardiovascular outcomes are not yet fully understood. Intensity matching threshold has been linked to longevity and mitochondrial efficiency, while enhancing capillary density and mitochondrial quality. This study focuses on reducing cardiovascular risk in T1DM through an unstructured low-intensity physical activity five days per week for 30-60 min per exercise, per exercise, performed at the intensity matching aerobic threshold.

This is a randomized, parallel-assignment longitudinal study. Following a screening phase (0-4 months) to verify inclusion/exclusion criteria and baseline laboratory status, eligible participants had been randomized into two groups:

Experimental Group (Group A): Introduction of low-intensity aerobic activity five days per week for 30-60 minutes. The intensity is individually determined via cardiopulmonary exercise testing (CPET) to achieve training zone 2.

Control Group (Group B): Maintenance of low-activity lifestyle (not exceeding 30 minutes, less than five days per week).

The physical activity protocol is monitored using heart rate tracking (Garmin watches) to ensure patients stay within the prescribed intensity zones.

Assessment of glycemic control using the ambulatory glucose profile (APG) was conducted using a Guardian 4 continuous glucose monitoring (CGM) system (Medtronic, Northridge, CA, USA).

The study evaluates the progression of Cardiovascular Autonomic Neuropathy (CAN) using the 24-hour Holter ECG monitoring to assess HRV

The assessment schedule is as follows:

Baseline (Month 0): Laboratory testing (CBC, UACR, HbA1c, BUN, eGFR, AST, ALT, CK, lipid profile), evaluation of microvascular complications, Cardiac ultrasound, HRV assessment ( 24h Holter), cardiopulmonary exercise testing (CPET), evaluation of glycemic control using the ambulatory glucose profile (APG).

Follow-up (Months 6): Repeat laboratory testing, cardiopulmonary exercise testing (CPET) and APG to track changes in cardiovascular fitness and metabolic control.

Final visit (Months 12): Repeat laboratory testing, evaluation of microvascular complications, HRV assessment and APG to track changes in cardiac autonomic function and metabolic control.

In addition, all subjects underwent CT coronary angiography. Long-term follow-up: Continuous monitoring every 6 months up to 60 months to evaluate the long-term sustainability of the intervention's effects on cardiovascular health and chronic vascular complications Objectives The primary goal is to determine if consistent, low-intensity exercise can delay the onset of CAN or to prevent progression of incipient CAN and improve cardiovascular fitness.

Study Type

Interventional

Enrollment (Actual)

35

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Bosnia and Herzegovina
      • Banja Luka, Bosnia and Herzegovina, 78000
        • University Clinical Centre of the Republic of Srpska

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Diagnosis of Type 1Diabetes at least six months prior to study enrollment
  • Male or female patients over 18 years
  • Willingness to perform physical activity 5 days/week.
  • Absence of heavy, chronic microvascular complications.
  • Absence of established Cardiovascular neuropathy.
  • Absence of established ASCVD.

Exclusion Criteria:

  • Type 2 Diabetes
  • Active engagement in professional sports
  • Limb amputation
  • Blindness
  • Active malignancy

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Prevention
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Experimental group
The exercise group will consist of patients with type 1 diabetes who will perform low-intensity physical activity in the postprandial period five days per week over a one-year observation period.
Behavioral: low-intensity physical activity
The exercise intervention consists of low-intensity physical activity (brisk walking) lasting 30-60 minutes, performed five times weekly. Participants will maintain a workload corresponding to Training Zone 2 over the course of the one-year follow-up.
Other: Intensive insulin therapy
The patients with diabetes type 1 in Control group will be physical active (low-intensity physical activity) less than five days per week (not exceeding 30 minutes per activity).
Active Comparator: Control group
Type 1 diabetes patients characterized by a sedentary lifestyle, defined as engaging in low-intensity physical activity less than five days per week.
Other: Intensive insulin therapy
The patients with diabetes type 1 in Control group will be physical active (low-intensity physical activity) less than five days per week (not exceeding 30 minutes per activity).

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Heart Rate Variability (HRV) parameters.
Time Frame: Twelve months from the baseline.

Assessment of HRV as a marker for Cardiovascular Autonomic Neuropathy (CAN). The measurement tool is a 24-hour Holter ECG monitor. Specific parameters include the Standard Deviation of NN intervals (SDNN) and Root Mean Square of Successive Differences (RMSSD).

Unit of Measure: Milliseconds (ms).
Twelve months from the baseline.

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Time in Range (TIR).
Time Frame: Six and twelve months from the baseline.
Assessment of glycemic control using the Guardian 4 Continuous Glucose Monitoring (CGM) system. TIR is defined as the percentage of time spent within the glucose range of 3.9-10.0 mmol/L. Unit of Measure: Percentage (%) of time.
Six and twelve months from the baseline.
Change in Urine Albumin-to-Creatinine Ratio (UACR).
Time Frame: Six months from the baseline.
Assessment of renal microvascular function via laboratory urinalysis. Unit of Measure: milligrams per gram (mg/g).
Six months from the baseline.
Change in Peak Oxygen Consumption (VO2 peak)
Time Frame: Six months from the baseline.
Evaluation of cardiovascular fitness through maximal cardiopulmonary exercise testing (CPET) Unit of Measure: milliliters per kilogram per minute (ml/kg/min).
Six months from the baseline.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Banja Luka

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

February 22, 2024

Primary Completion (Actual)

February 22, 2026

Study Completion (Estimated)

June 1, 2026

Study Registration Dates

First Submitted

January 7, 2026

First Submitted That Met QC Criteria

January 25, 2026

First Posted (Actual)

February 3, 2026

Study Record Updates

Last Update Posted (Actual)

April 16, 2026

Last Update Submitted That Met QC Criteria

April 13, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • PAT1D2025

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

Individual participant data that underlie the results reported in our article (text, tables, figures, appendices) will be shared with researchers to achieve the aims of their approved proposals.

IPD Sharing Time Frame

Data will be available beginning six month following publication of the final study results and will be available for up to three years.

IPD Sharing Access Criteria

Data request should be submitted to the Principal Investigator. Data requestors will need to sign a data access agreement and provide a scientifically sound research proposal.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • SAP
  • ICF

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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